ELEKTRONIKA, ENERGETYKA, ELEKTROTECHNIKA ›
ELEKTRONIKA - KONSTRUKCJE, TECHNOLOGIE, ZASTOSOWANIA ›
2011-3 |
| |
|
Publikacja: Maskless laser lithography for fast Microand Nanotechnology devices prototyping in ITE
Autor: ANDRZEJ SIERAKOWSKI  KRZYSZTOF DOMAŃSKI PAWEŁ JANUS PIOTR GRABIEC TEODOR GOTSZALK DANIEL KOPIEC
Production of MEMS/MOEMS on silicon substrates requires
specific technological sequences significantly different from
those used in fabrication of Integrated Circuits (ASICs). Applications,
such as transducers, AFM probes, gripers are 3-
dimensional, while ASICs are located within a thin top layer of
a substrate. In the case of MEMS/MOEMS the entire volume
of the substrate may play an important role being a functional
part of the instrument e.g. mirrors, mobile parts of an actuator,
bio-cells. To produce such a type of structures, in addition to
a standard technological sequence, one may use deep silicon
etching processes (wet and plasma). Often used silicon
<100> anisotropic etching technology leads to slant-angle
sidewalls. Some applications require placing a metal path
going across the sloped area. Performing photolithography
makes in such a case many difficulties, mainly because of the
variable resist thickness. On expanded topographies, where
the sloping surfaces exist, the resist layer is thicker close to
the lower edges and thinner close to the top surface. In addition,
one can observe an effect of decreasing the metal path
width situated close the sloping surfaces resulting from additional
resist exposure by light reflected from the mirror surface
<111>. During developing of a MEMS/MOEMS new application
very often is necessary to test more than one option of the
design. Especially photolithography processes require such
a type of optimization. Vario[...]
|
Prenumerata
|
|
A low-cost impedance measurement technique for thick-film electronic components diagnostics
|
|
|
MARCIN W. DUDEK KAROL NITSCH ANDRZEJ DZIEDZIC
|
Fabrication of thick-film electronic components (resistors,
capacitors, varistors) involves a lot of still developing techniques:
screen printing, photoforming, direct write printing,
liquid ink jet printing, laser trimming etc. Different methods of
production result in various electrical properties of fabricated
components. Electrical impedance is the main physical parameter
that fully characterize alternating current properties
of electronic components. The main technique to investigate
AC properties is impedance spectroscopy [1]. Full characterization
of electrical properties requires wide frequency range
measurements which normally need precise and expensive
analyzers [2].
Simple and inexpensive Virtual Instrument setup and impedance
calculation algorithms that are proposed in this paper
ensure that first basic post-process quality check of fabricated
thick-film structures can be obtained on place in the technological
laboratory without need of high cost precise measuring
devices which are always complicated to operate and needs
qualified metrological personnel.
Principle of measurement
Basically, we can describe impedance as a complex number
that represents current response for voltage perturbation (and
vice-versa). For sinusoidal signal this response is seen as an
amplitude change and time delay of response signal (described
as an angular part of period) - Fig. 1.
Using simple calculations we can transform impedance
(dependent on perturbation frequency) to other useful object
parameters (admittance Y(ω), complex capacitance C(ω) and
electrical modulus M(ω)) as well as material parameters (resistivity
ρ(ω), conductivity σ(ω), permittivity ε(ω), and modulus
m(ω)) - Fig. 2.
Classic techniques of impedance measurement include
impedance bridges or resonant bridges. First method can
cover frequencies from DC to 300 MHz, second one is suitable
only for frequencies higher tha[...]
|
|
|
|
A novel experimental setup for accelerated reliability assesment of solder and adhesive joints
|
|
|
KRZYSZTOF MAŁECKI KRZYSZTOF URBAŃSKI ARTUR WYMYSŁOWSKI
|
A continuously growing demands for customer electronics
focus on miniaturisa-tion, higher reliability and faster product
commercialisation. They are fulfilled primarily through an investigation
and development of new methods for assembling,
packaging, and dies integration. In reality, advanced technological
apparatus and materials science play here predominant
role. In parallel, the strong expansion on nanotechnology introduces
new polymer materials and fillers, such as nanosilver
(nanoAg) or carbon nanotubes (CNT), with combination
of wide spectra front-end and back-end processing, opens
completely new window for application performance and usability.
However, these new opportunities force an extreme
challenges on whole scientist and technology communities.
Although, there are several advanced techniques for materials
base parameters investigation, the final assessment of
materials quality and ultimate product usability can be performed
by means of reliability tests, which are the most accurate
way to predict time to failure of any devices and electronic
components.
A spectra of tests potential of developed failure and reliability
investigation system (FRIS) is reported in this paper. It
base on a self-developed electronic control and data acquisition
system, operated with innovative setup (allowing simultaneous
load of different stresses and on-line monitoring the
response of subjected sample). This approach allows in depth
investigation of solder and adhesive joints reliability for electronic
applications.
Solder and adhesive joints -reliabilllity
consideration
Soldering is a well-established process that has been utilized
and optimized for decades. In natural consequence, soldered
joints are widely used in electronic packaging to form[...]
|
|
|
|
A/D converter for sensor characteristics linearization
|
|
|
EDWARD HRYNKIEWICZ
|
Due to the obvious fact that sensors transfer characteristics
are often non-linear, it is necessity to carry-out a linearization
of such characteristics. It may be done by introducing
nonlinearity to a measurement transducer, by applying static
converter with reverse nonlinearity to a sensor characteristic
or in microprocessor system by software way or by using
memory as a look-up-table converter [1, 4, 6]. But if digital
signal processing is used it is necessary first to convert an
analogue measured value to a digital one using A/D converter
and next carried-out a linearization. Such approach is time
and resources consuming. The author of this work proposes
to use linearizing A/D converter for such purposes [1]. The linearization
may be carried-out during conversion time what is,
for instance, important for fast operating PLCs. Two types of
linearizing A/D converted are considered: A/D converter with
voltage-to-frequency indirect conversion and dual slope A/D
converter. Both approach are suitable to use with measuring
transducers.
Linearizing A/D converter with
intermediate U/f conversion
When in measuring system an A/D converter with indirect U/f
conversion is used a linearization of transducer transfer characteristic
can be completed by introducing a rate multiplier
[2, 5] between U/f module and a pulse counter. The programming
numbers applied to a rate multiplier are set-up in such a
manner that the linear relat[...]
|
|
|
|
Analysis of thickness influence on wettability of ITO thin films
|
|
|
MICHAL MAZUR DAMIAN WOJCIESZAK JAROSŁAW DOMARADZKI KAROLINA SIERADZKA DANUTA KACZMAREK SHIGENG SONG FRANK PLACIDO BARBARA GORNICKA
|
Tin doped indium oxide (ITO) thin film is a highly degenerated
wide gap semiconductor with good conductivity and high optical
transmission within the visible spectrum. Due to unique
properties, the ITO films have many applications in solar cells,
flat panel displays, sensors and organic light emitting diodes
(OLED) [1,2]. Reproducible ITO films can be prepared by various
methods, including reactive evaporation [3], reactive DC
or RF sputtering [4], sol-gel process [5] and chemical vapor
deposition (CVD) [6]. Among the mentioned methods, reactive
DC or RF magnetron sputtering is the most frequently used
ITO deposition methods for optoelectronic device manufacturing
because of high sputtering rates that can be obtained at
large area coatings [7]. Indium tin oxide coatings are suitable
for a wide range of transparent EMC shielding and anti-static
applications [8]. The optoelectronic and mechanical properties
of ITO films are critical to the development of flexible optoelectronic
devices [9].
Contact angles have great potential utility. They can be
measured on a macroscopic level to characterize the average
wettability of materials. Knowledge of the macroscopic
contact angle for materials allows to predict whether a liquid
droplet will bead up on or spread out over a solid surface. In
their macroscopic use, contact angles are key in measuring
the wettability of the surfaces [10]. The water contact angle is
often used as a measure of surface hydrophobicity, i.e., the
higher the contact angle is, the more hydrophobic the solid
Analysis of thickness influence on wettability
of ITO thin films
(Analiza wpływu grubości na zwilżalność cienkich warstw ITO[...]
|
|
|
|
Ball Grid Array failure diagnosis
|
|
|
BARBARA DZIURDZIA
|
Ball grid array (BGA) packages, in which connections with
outside circuits are performed through solder balls under a package,
has become popular in recent years. BGA packages
offer a much larger I/O counts for a given footprint area on
a PCB as compared to a peripherally leaded devices such as
quad flat pack (QFP). They provide also improved electrical
performance, e.g. a lower electrical inductance and they are
much more easy to handle and assembly without the concerns
of lead coplanarity and bent leads. The disadvantage of
the BGA configuration is, that visual inspection and individual
repair of defective solder joints is difficult. Repair and rework
has to be done by removing the entire defective BGA package
and replacing it with a new or a reballed one [1, 2, 3].
The paper presents the methods of BGA failure diagnosis
after rework. The rework was accomplished by two methods:
with professional hot air rework station and with solder paste
and equipment for SMT assembly. BGA inspection is carried
out by electrical continuity tests, X-ray inspection, acoustic
microscopy and metallographic cross-sections. The effect of
thermal shocks (‑55°C, +125°C) and the sine wave vibrations
in the frequency range from 20 Hz to 1,4 kHz on the BGA solder
joint features is investigated.
Test patterns
BGA packages used in experiments were test components
of BGA225T1.5C-DC15 type manufactured by the TopLine.
They were 225-ball fine-pitch Plastic Ball Grid Arrays (FBGAs)
with lead-free solder balls deposited on the BT (bismaleimide
triazine) substrate of thickness 0.36 mm. The balls of diameter
0.76 mm and 1.5 mm pitch were made of Sn96.5Ag3.0Cu0.5
solder alloy. Fig. 1 shows the ball grid array in Hirox stereomicroscope.
Fig. 2 shows the test component BGA225T1.5C-DC15
- its top view and the daisy chain loop.
The BGA components were daisy chained "dummy components".
Daisy chains provide information about the continuity
of the BGA assem[...]
|
|
|
|
Characterisation of a heterojunction structure based on Au doped WO3 and SnO2
|
|
|
PATRYK HALEK HELENA TETERYCZ MARTA FIEDOT KAMIL WIŚNIEWSKI
|
Gas and humidity sensors based on semiconductor metal oxides
and solid electrolytes have been studied extensively during
the last few decades. The main work in this area is aimed
at improving the basic parameters of these sensors to achieve
better sensing performance. Nowadays there are a variety of
commercial available sensors. Nonetheless it has not been
possible to make a highly selective and sensitive sensor with
fast response time.
The presence of various gases or water vapour in the
atmosphere affects the sensor performance and influence
the output signal. Semiconductor gas sensors show poor
selectivity, which makes them insensitive to low gas concentrations.
Several methods have been found to overcome this
problem. The most frequently used methods are the modulation
of the working temperature of the sensing structures
and the application of new materials with improved catalytic
properties [1, 2].
Another option is the construction of semiconductor gas
sensors based on a heterojunction formed between different
metal oxides. The analysis of reactions occurring in the single
phase materials and at the junction can improve the selectivity
and sensitivity of such structures. For the first time this class
of devices was used as humidity sensors. For the application
in measurement systems, both p-n and n-n junctions were
propsed by authors [3-5].
In this paper we study[...]
|
|
|
|
Characterization of mos structures with ultrathin insulator layer by means of a theoretical model
|
|
|
BOGDAN MAJKUSIAK
|
Thickness of the gate oxide layers in the metal-oxide-semiconductor
structures in the most advanced technologies has reached
the range of a single nanometer and further scaling requires
replacement of SiO2 by material of high electric permittivity
because of the flow of unacceptable tunnel leakage current. Tunnel
leakage affects also the admittance of the MOS capacitor
which serves as the basic characterization and diagnostics tool.
The aim of this work is to study the effect of the tunnel leakage on
the capacitance and conductance - two components of the simplest
small-signal equivalent circuits of the MOS structure. These
quantities are computed with the use of a theoretical model.
Conclusions from the theoretical considerations are reviewed for
measurements of the fabricated Al-SiO2-Si capacitor.
Small-signal equivalent circuit
Fig. 1 shows a simple small-signal equivalent circuit of an MOS
structure, which this study is based on. The capacitance CMOS
representing an idealized MOS structure is shorted by the leakage
conductance GL (resistance RL) reflecting tunneling
through the insulator layer, and is connected with the series
resistance RS representing the spreading resistance of the semiconductor
substrate and the contact resistance.
Simple transformations lead to relations between elements
of the equivalent circuit shown in [...]
|
|
|
|
Electrocatalytic gas sensor with non-triangular excitation
|
|
|
GRZEGORZ JASIŃSKI ANNA STRZELCZYK BOGDAN CHACHULSKI PIOTR JASIŃSKI
|
In recent years, solid state ion conducting materials have been
intensively developed. These materials have a relatively high
ionic conductivity based on a single predominantly conducting
anion or cation species and have negligibly small electronic
conductivity. Typically, useful solid electrolytes exhibit ionic
conductivities from 10-1 to 10-5 S/cm at room temperature.
Solid state electrolytes exhibit a potential for application in
a variety of solid state electrochemical devices such as fuel
cells, batteries, membranes, pumps and sensors [1].
Gas sensors are one of the most critical and rapidly growing
areas in modern solid electrolyte technology. Solid state
gas sensors are cost effective, small, rugged and reliable
[2, 3]. Usually electrochemical solid state sensors operate in
either potentiometric or amperometric mode [4, 5]. A lack of selectivity
is sometimes a shortcoming of such sensors. It seems
that improvements of selectivity can be obtained in case of the
electrocatalytic sensors. Their working principle is based on
acquisition of an electric current, while voltage ramp is applied
to the sensor. The current-voltage response depends in a unique
way on the type and concentration of ambient gas.
In case of electrocatalytic gas sensors usually a linearly
changing voltage excitation signal of symmetrical triangular
shape in range from 5 to -5 V is applied to the sensors terminals
[6]. The voltage sweep rate is adjusted to 50 mV/s.
This, originated from liquid electrochemistry, method has
some shortcomings. In typical conditions, one measuring cycle
takes up to 7 min. Stable response is obtained most often
after 2 or more cycles, thus extending measuring time even
further. Long measuring time can limit application of electrocatalytic
sensors in environments with fast gas concentration
changes.
In th[...]
|
|
|
|
Environment for automated low-temperature measurements of electronic circuits
|
|
|
FRANCISZEK BALIK WOJCIECH SOMMER
|
The aim of this work was to develop an environment which
would allow us to perform automated measurements of electronic
circuits and elements characterization in low-temperature
conditions. For instance, the characteristics of transistor or
integrated amplifiers, or thick-film resistor parameters can be
measured by using this system in wide temperature range.
Hitherto, cryostat automatic systems have been mainly developed
for chemical material measurements in low-temperatures.
The physical properties of such materials were tested in
cryogenic temperatures, for instance, molecular magnetic or
superconducting properties were examined for newly invented
chemical compounds [1, 2]. Some of these systems worked
under RS bus and computer Visual Basic programs control [1,
3] or were supplied with specialized control programs.
In general, the cryostat systems can be divided on four
groups [4]:
1. Dipper probes,
2. Liquid-flow cryostats,
3. Gas-flow cryostats, and
4. Cryocoolers.
The dipper probe is the simplest type of cryostat, in which
the test sample is mounted on a copper block at the end of
a low-thermal-conductivity tube placed above the cryogenic
liquid surface in a storage Dewar. By varying the height of
the sample-probe above the liquid surface, the sample-holder
temperature can be varied. This kind of cryostat sometimes
can suffer from collecting ice on probe tube and making the
sample temperature instability.
The test sample in the liquid-flow cryostat is thermally
mounted on a copper cold plate inside a container. The cold
plate is cooled by continuously transferring a liquid cryogen
from a supply Dewar to the cold plate. The temperature of the
cold plate is set near the desired temperature by adjusting
the flow rate of cryogen. This kind of cryostat can cover temperature
range: 4-300K, and temperature can be controlled
typically to within about +/-2 mK.
The gas-flow type cryostat is some modification of the
previous[...]
|
|
|
|
Etching of Si(100) and (110) substrates in KOH solutions saturated and son-saturated with isopropyl alcohol
|
|
|
KRZYSZTOF ROLA IRENA ZUBEL MAŁGORZATA KRAMKOWSKA
|
Anisotropic etching of silicon is commonly used to fabricate
spatial MEMS and MOEMS structures applied in micromechanics
and optoelectronics. The most popular are KOH and
TMAH solutions, both pure as well as containing different alcohol
or surfactant additives. The additives to the basic solutions
change the etching anisotropy and cause some reduction of
etch rates of several crystallographic planes, like (110), (331)
and (221) what is used to reduce the convex corners undercut.
The solution of KOH with isopropyl alcohol (IPA) is currently
the most frequently used in silicon anisotropic etching.
The process is usually carried out in the solutions saturated
with IPA since it guarantees stability of the solution composition
and the best morphology of (100) plane which is the most
commonly used in micromechanical devices [1].
In the paper, the results of etching in KOH solutions with
IPA content below saturation are compared with the results
of etching in KOH solutions saturated with IPA. The analysis
of the etching process in these solutions may be useful for
explaining the etching mechanism.
Etching in KOH solutions saturated with
isopropyl alcohol
The etching experiments were carried out in a thermostated
vessel at the temperature of 75ºC, with the use of mechanical
stirring. The etching rates of (100) and (110) planes obtained
in KOH and KOH saturated with IPA solutions are shown in
Figs. 1 and 2. The morphologies of the surfaces obtained after
the etching are shown in Figs. 3 and 4. The obtained results
show that in pure KOH solutions with the concentration
exceeding 7 mol, smooth Si (100) surfaces, etched with the
Fig. 1. Etch rates of the silicon substrates
Rys. 1. Szybkości trawienia podłoży
2 4 6 8 10 12
0,5
0,6
0,7
0,8
0,9
1,0
1,1
etch rate [um/min]
KOH concentration [M]
(100) KOH
(100) KOH+IPA
2 4 6 8 10 12
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
etch rate [um/min]
KOH concentration [M]
(110) [...]
|
|
|
|
Fabrication of through-holes in GaAs substrates for device applications
|
|
|
IRENA ZUBEL PMAŁGORZATA KRAMKOWSKA IWONA ZBOROWSKA-LINDERT
|
Device structures on AIIIBV substrates (MESFETs, p-HEMT,
integrated circuits MIMICs), intended for the operation at high
power and high frequency range, require specific conditions
of heat dissipation and minimizing of parasitic capacities and
resistances, which affect their electrical performance and response
time. Reduction of dimensions, including reduction of
substrate thickness, in order to obtain higher integration level
is also very important.
To fulfill the mentioned requirements, via-type connections,
giving the possibility to produce contacts from the backside of
the substrate, are created. Such connections facilitate heat
dissipation and reduce substrate impedance of high frequency
devices. They are widely used in silicon technology, though
in the case of AIIIBV compounds, are not so popular. The fact
follows probably from much more complex technological process,
which is involved in their fabrication.
Some examples of implementation of the technology in
GaAs sensor applications will be also discussed at the end
of this paper.
Designing of technological process
Theoretical considerations
Accomplishment of via-type connections for semiconductor
structures made on epitaxial layers of AIIIBV compounds by
wet chemical etching imposes many technological problems.
They include: thinning of substrates, etching of a hole itself,
stopping of etching process at an etch-stop layer.
Chemical etching of the holes with micrometric dimensions
in the wafer with a typical thickness of few hundred micrometers
could result in significant undercut of the etching mask
and remarkable extension of the hole size (the lateral underetching
is usually comparable with the etching depth). To assure
appropriate miniaturization, preliminary thinning of the wafer is
necessary. Uchiyama et al [1] employed mechanical grinding
and polishing to thin the backside of the wafer up to 30 μm.
We have used wet chemical etching for this purpose. App[...]
|
|
|
|
Fotonika i Inżynieria Internetu
|
|
|
RYSZARD ROMANIUK
|
Fotonika, zaawansowane systemy elektroniczne oraz inżynieria
Internetu rozwijają się w kraju intensywnie, głównie na terenie
uczelni i w instytutach badawczo-rozwojowych. Zapotrzebowanie
na specjalistów inżynierów w zakresie zaawansowanego
sprzętu i oprogramowania systematycznie wzrasta w kraju.
Tradycyjne, XXVII Sympozjum Zespołu Naukowego PERG/
ELHEP z Instytutu Systemów Elektronicznych WEiTI Politechniki
Warszawskiej odbyło się w dniach 4-5 lutego 2011 r. na terenie
Wydziału Elektroniki i Technik Informacyjnych PW. Patronami
Sympozjum są: WEiTI PW, IEEE, SPIE, Komitet EiT PAN
oraz Polskie Stowarzyszenie Fotoniczne. W Sympozjum wzięło
udział ok. 60 osób, głównie magistrantów i doktorantów PW
oraz z współpracujących instytucji jak: IFD UW, IPJ, IFPiLM,
ZFT PAN oraz CBK PAN. Wygłoszono kilkadziesiąt prezentacji
naukowych dokumentujących postęp w pracach wykonywanych
przez młodych naukowców na rzecz prowadzonych projektów
badawczych, a także prac inżynierskich, magisterskich
i doktorskich. Sympozjum obejmowało następujące sesje: IT
w medycynie, eksperymenty fizyki wysokich energii, inżynieria/
elektronika kosmiczna, czujniki sCCD i techniki obrazowania
ultra-nisko-szumnego w pasmach optycznych i IR, nowe rozwiązania
kart elektroniki z procesorami FPGA-DSP, efektywne
komponentowe metody [...]
|
|
|
|
Further improvement of Pb/Cd-free CaRuO3 thick-film resistors
|
|
|
ADAM WITOLD STADLER ZBIGNIEW ZAWIŚLAK ANDRZEJ KOLEK KONRAD RAFAŁ KIEŁBASIŃSKI MAŁGORZATA JAKUBOWSKA
|
Thick-film resistors (TFRs) are very popular in many fields
of electronics. They are typically made from pastes containing
conducting (RuO2, Bi2Ru2O7 or CaRuO3) and Pb-containing
glass components as well as organic vehicle, which are
screen-printed on substrates and then fired in low or high
temperature processes. TFRs gained many proponents over
years of their usage, due to their advantages, as cheap technology,
good performance parameters, and easy control of
sheet resistance. On the other hand, RuO2-based resistors
enter very demanding field of temperature sensing in cryogenics.
Novel technique called printing electronics, in conjunction
with eco-friendly materials, opens new page and
makes thick-film technology still perspective. However, it implies
design of new materials, like Pb/Cd-free solders and
pastes for TFRs, what is challenge for technologists who
have to develop new generation of materials. For example,
well known and widely used in TFRs fabrication RuO2-based
resistive pastes include lead-borosilicate glass and therefore
they do not fulfill RoHS directive and have to be replaced with
their Pb/Cd-free counterparts. Unfortunately, in spite of great
effort, Pb/Cd-free TFRs are still at the explorative stage [1-5].
However, first attempts, suggest that CaRuO3 better works
with Pb/Cd-free glasses [4] and therefore it is more promising
conducting component than widely used RuO2. On the
other hand, currently Pb/Cd-free CaRuO3-based TFRs are
noisier than Pb/Cd-free RuO2-based or Pb-containing TFRs
and form bad interface at least with Pb/Cd-free AgPd-based,
contacts [6].
In this work we present our new results concerning studies
of electrical properties of Pb/Cd-free CaRuO3-based TFRs.
The innovation is that the resistive paste was made of the
conducting component which is the mixture 1:1 of CaRuO3
and RuO2 powders. Resistance vs. temperature measurements
and low-frequency noise spectroscopy methods have
been applie[...]
|
|
|
|
Hall Mobility in 4H-SiC, measurements and Monte Carlo simulation
|
|
|
JANUSZ WOŹNY GESUALDO DONNARUMMA ZBIGNIEW LISIK
|
Silicon Carbide is used as material for electronics working in
difficult conditions (temperature, power densities, high speed).
Although its technology can be almost considered as matured
commercial CAD tools e.g. like Sentaurus TCAD suffer from
not-well established models, e.g. lack of robust model for breakdown
modelling [1]. Also parameters of the models are not
measured as accurate as for silicon. For instance drift velocity
values are mostly quoted only from Khan and Cooper measurements
[2]. Knowledge about material parameters for wide
range of environmental conditions (various temperatures,
electric fields, etc ...) is required for proper functioning of CAD
tools. One way of retrieving the values is to do measurements
which is impossible for all combination of environmental variables.
Second possibility is to use very accurate models and
obtain macroscopic parameters from simulation. Here we use
the Monte Carlo approach to obtain Hall mobility for 4H-SiC.
Results were verified with measurements done with Van Der
Pauw method. Good accuracy of modelling was observed
thus the Monte Carlo simulations can be seen as a[...]
|
|
|
|
Humidity sensor made by ink-jet printing technology
|
|
|
JERZY WEREMCZUK GRZEGORZ TARAPATA ROMAN IWASZKO DANIEL PACZESNY RYSZARD JACHOWICZ
|
The ink-jet printing technology seems to be very promising
for all: small, medium and large volume production of cheap
sensors dedicated for applications of everyday life like smart
packaging, smart textiles, smart labels, etc. To achieve this
goal new technologies and materials compatible with ink-jet
printing and offset printing should be developed.
Presented in the paper humidity sensor was made with the
usage of ink-jet technology (Dimatix DMP 2831). In comparison
to the sensors reported in the literature [1,2] complicated
silk screen printing was eliminated.
Printing technology
The Dimatix DMP 2831 printer is capable to print with different
solutions using MEMS piezoelectric printing head equipped
with 16 nozzles of diameter and pitch of 21,5 and 254
μm respectively. Typically droplet volume is of 10pl (Fig. 1).
To avoid nozzles clogging a 200 nm mesh filter was applied.
Each nozzle could be controlled separately and trimmed by
changing of its supplying voltage (16…40 V) to achieve uniform
droplets. The printed dot diameter was about 42 μm,
therefore it was decided to use 30 μm printing resolution
(both X and Y direction) to have a dot overlapping to gain
tracks continuity.
Sensor construction
The humidity sensor was designed in a form of interdigitated
electrodes covered by humidity sensitive layer (Fig. 2). It was
designed two types of sensor differing each other electrodes
widths: 200 and 100 μm respectively. The gap between the
electrodes was of 100 μm. Each comb ele[...]
|
|
|
|
IGBT static model based on diffusion equation implemented in SPICE source code
|
|
|
ŁUKASZ STARZAK ANDRZEJ NAPIERALSKI
|
Bipolar power semiconductor devices, such as the PIN diode
or the Insulated Gate Bipolar Transistor (IGBT), have the advantage
of low voltage drop at high current densities. This is
achieved through introduction of excess carriers into the wide,
lightly doped base layer which is necessary for obtaining high
voltage capability.
A power semiconductor device is normally used as a switch.
Bipolar power device switching takes more time and involves
physical phenomena more complex than in the case of unipolar
devices such as the power MOSFET. Thus, excess carriers
influence strongly static and dynamic properties of the device.
This causes problems when the device is used in a circuit but
also makes its modelling more troublesome [1].
Motivation
Power semiconductor device models presently fall into one of
the following two categories.
1. Full physical models are based on microscopic description
of physical phenomena and take into account the dimensions
of the semiconductor structure. They are very accurate,
yet not accessible to the average electronic engineer. They
need special, multidimensional simulators that are costly and
need special skills to be used. Moreover, geometrical and
physical parameters must be known that are obviously not
made available by device manufacturers.
2. In the widely used electronic circuit simulators, compact
behavioural models are used. They are easy to use for circuit
designers but yield inaccurate or even erroneous results. This
is because they are either models of signal-oriented devices
(as opposed to power-oriented ones) developed for the needs
of VLSI circuit design,[...]
|
|
|
|
Implementation of FD SOI CMOS technology in ITE
|
|
|
KRZYSZTOF KUCHARSKI CHRISTIAN RENAUX ANDRÉ CRAHAY PIOTR GRABIEC MIROSŁAW GRODNER TOMASZ BIENIEK ANDRZEJ PANAS ANDRZEJ SIERAKOWSKI HELENA KŁOS DANIEL TOMASZEWSKI DARIUSZ OBRĘBSKI JACEK MARCZEWSKi DENIS FLANDRE
|
Fully-depleted silicon-on-insulator (FD SOI) CMOS technology
is widely used for fabrication of low-power, low-voltage
CMOS integrated circuits (ICs) [1]. Interest in SOI CMOS
technology in ITE dates to the late 90s. Different aspects of
SOI technology have been considered, e.g. modelling of PD
SOI MOSFETs, as well as integration of CMOS on thick SOI
substrates with p-n junction based detectors of ionizing radiation
[2, 3]. Recent works also comprise development of
FinFET-type devices for application as chemical detectors [4].
Thus a variety of SOI CMOS technologies are under continuous
development.
These applications, except for the FinFET-based one, have
not taken advantages of FD SOI technology: better channel
operation control by gate voltage, better subthreshold I-V characteristics,
lower p-n junction area and capacitance, thus lower
leakage, power consumption and higher speed, as well as
wider range of temperature operation. In order to fill this gap,
a collaboration with UCL has been undertaken, and supported
by TRIADE project [5]. The collaboration aims at transferring
the FD SOI CMOS technology, originally developed at UCL
[1], to ITE. Main features of this process are as follows: supply
voltage 3 V, threshold voltage 0.3 V, and min poly-silicon gate
width 1.5 μm. In the sections below issues related to the task
mentioned above are reported.
SOI substrates
A recommended method for fabrication of high-quality 4-inch
SOI substrates (requirement of ITE facilities) consists in laser
cutting of the 200 mm UNIBOND SOI wafers manufactured
originally by SOITEC. At present they represent the top quality
with respect to thin silicon layer properties (crystallography,
Si/SiO2 interface quality, thickness, and its uniformity), which
are very relevant for manufacturing of the FD SOI CMOS devices.
Method and equipment for laser cutting of 200 mm wafers
have been developed in ITE. In Fig.1. the way, in which
the 200 mm SOI U[...]
|
|
|
|
Influence of Selected Constructional and Technological Factors on Tolerance and Stability of Thin-Film Resistors Embedded in PCBs
|
|
|
WOJCIECH STĘPLEWSKI JANUSZ BORECKI GRAŻYNA KOZIOŁ ANETA ARAŹNA ANDRZEJ DZIEDZIC PIOTR MARKOWSKI
|
In the study the OhmegaPly? material was selected to forming
resistors. The commercial available material is produced by
deposition the resistive layer (Ni-P) on copper foil and lamination
onto FR4 material. Resistivity of Ni-P layer depends on
thickness of this layer and can be in range from 10 Ω/□ to 250
Ω/□. In the investigation it was used material with sheet resistance
of 25 Ω/□ (thickness - 0.4 μm) and 100 Ω/□ (thickness
- 0.1 μm). Thin-film character of the resistor cause that it can
be embedded inside of PCB without increasing its thickness.
The other advantage is that embedded resistor is not assembled
in the contrast to conventional element so the number of
component solder joints will decrease and this can improve
reliability of final product. However, the resistive layer is very
thin and simultaneously it has very rough surface (Fig. 1).
It can be the reason that the thin-film resistive layer is sensitive
to mechanical factors (scratch, stress during lamination)
and also on chemicals that are used in PCB manufacturing
process.
Influence of crucial constructional factors such as size,
shape and resistors orientation as well as technological parameters
of resistor forming process and PCB manufacturing
process on the tolerance and stability of embedded resistor
parameters was assessed.
The experiments were carried out both in the laboratory
and on technological line at Tele and Radio Research Institute.
The Sequential Build Up technology was applied to manufacture
PCBs with thin-film embedded resistors.
The results revealed that some factors can accumulate or
neutralize each other influence on the final value of resistance
also in dependence on the existing manufacturing processes
and production facilities. The knowledge on changes in resistors
properties introduced by individual parameters of the
design and technological processes is a crucial issue before
intr[...]
|
|
|
|
Investigation of inkjet technology for printed organic electronics
|
|
|
JANUSZ SITEK KONRAD FUTERA KAMIL JANECZEK KRYSTYNA BUKAT WOJCIECH STĘPLEWSKI MAREK KOŚCIELSKI MAŁGORZATA JAKUBOWSKA
|
The new fields of applications are now opened up thanks to
organic electronics. This technology is combination of new
material and cost-effective printing processes and enables
manufacture of low cost, light-weight and flexible devices in
single process. Flexible solar cells, printed batteries, screens
printed on paper are only examples of promising application
for this new technology.
The most important property of organic electronic is its
“flexibility". This feature unable use in production of cost-effective
techniques, such as roll-to-roll, that require expensive
tools but give us very high efficiency in large scale production.
Organic electronic can be also manufactured using smaller
and lower cost inkjet printers. That can be used in small companies
and research institutes. Inkjet printers can lower the
cost of prototypes and small series, because no other tools
are necessary. Paper presents the self build inkjet printer system
as well as results of manufacturing electronic elements on
different substrates. Structures were characterized from the
point of shape of surface and geometry. The PEDOT:PSS and
nanosilver inks were used in investigations.
INKJET printer for organic electronics
The investigations were carried out on self build inkjet printer
system. The printer was based on MicroDrop piezoelectri[...]
|
|
|
|
Laser micromachined LTCC gas sensors
|
|
|
ADAM BIEŃKOWSKI JANINA GAUDYN KRZYSZTOF ZARASKA ARTUR RYDOSZ WOJCIECH MAZIARZ KAROL MALECHA
|
The low temperature co-fired ceramics (LTCC) is a well known
technology used to produce multichip ceramic modules. This
technology is mostly used for production of microwave devices
and hybrid integrated circuits [1]. Recently, LTCC was
also applied for the production of sensors and microsystems
[1-4] thanks to its very good electrical and mechanical properties,
high reliability and stability as well as possibility of making
three-dimensional structures. This is a continuation of earlier
work on this subject [2]. Our aim was to further reduce the
size of the sensor. Smaller size of the sensor would decrease
its heat capacity thus reducing power consumption. The gas
sensor substrates described in this paper will be used with
gas sensitive layers based on nanopowders and nanotubes.
These materials are now under development.
Design
The sensor consists of 3 layers of Heraeus CT700 tape (200
μm thickness) with 3 mm diameter (after firing). On the b[...]
|
|
|
|
Laser patterning of coloured green ceramic tapes
|
|
|
KAROL MALECHA DOMINIK JURKÓW JOHANNA STIERNSTEDT LESZEK GOLONKA
|
HTCC (High Temperature Cofired Ceramics) and LTCC (Low
Temperature Cofired Ceramics) technologies have been developed
for many years. Both techniques enable fabrication of
MCM-C (Ceramic Multi Chip Modules) devices [1]. Moreover,
various sensors, actuators and microsystems can be utilized with
these technologies [2-5]. Design flow of both methods consists
of: tape preparation, vias and shapes forming, conductive tracks
and passive elements deposition, stacking, lamination, cofiring
and post processing [6]. A traditional LTCC structure consists of
several (or more) dielectric tapes, connecting vias, surface and
buried conducting lines and passive components (resistors, capacitors,
inductors). The conductors and passive components
are deposited on ceramic tape using standard screen-printing
or ink-jet printing method. After deposition process all green ceramic
tapes are stacked together in proper order and burnlaminated
using an isostatic or uniaxial press with a pressure
of 5-30 MPa at temperature 40-90oC for time up to 30 minutes.
Then the ceramic module is cofired in air in special thermal profile
with a maximum temperature of 850oC (for LTCC) or 1600oC
(for HTCC). Afterwards active and passive components can be
added on the ceramic module’s surface using standard SMT
(Surface Mounting Technology) or flip-chip techniques.
Three main techniques of vias and three-dimensional structuring
of green ceramic tape are recently utilised: laser pattering
[7,8], hot embossing [9] and mechanical punching [10]. The laser
cutting is the most flexible method. It is used in low mass production
and in fast prototyping processes. However, the cutting
quality depends strongly on laser light absorption by the green
ceramic tape. Absorption depends on laser frequency, tape composition
and colour. Moreover, laser power and beam velocity affect
the cutting[...]
|
|
|
|
LTCC wireless module
|
|
|
LESZEK GOLONKA ZBIGNIEW IANELLI HENRYK ROGUSZCZAK JANUSZ SZTAJER PIOTR WOJTAS PRZEMYSŁAW WISZNIOWSKI DARIUSZ BABECKI
|
The LTCC (Low Temperature Cofired Ceramics) has been
used for many years to produce a multilayer substrate MCM
(Multichip Module) due to its very good electrical and mechanical
properties, high reliability and stability as well as possibility
of making three dimensional (3D) integrated microstructures
containing passive components [1-3]. This technology can
also be applied for the production of sensors, actuators and
microsystems integrated with wireless modules. Implementation
of modern LTCC technology together with the advanced
assembly techniques of electronic components allows a significant
miniaturisation of final product with increased performance
and reliability. LTCC electronic systems can work in
the highest frequency ranges of radio waves covering millimetre
waves or shorter.
The LTCC modules containing modern wireless communication
systems based on TN100 semiconductor manufactured
by the STMicroeletronic are investigated. The system
operates in the licence free 2.4 GHz ISM band and allows
creation of self-organizing and self-localizing networks. It uses
world-wide standardized communication technology based on
chirp modulation (CSS-Chirp Spread Spectrum). Extensive
tests of the LTCC wireless systems have been carrie[...]
|
|
|
|
Mikrokontrolery PIC w zastosowaniach badawczych Część 3: Obsługa alfanumerycznego wyświetlacza LCD. Przerwania. Przerwanie zewnętrzne INT/RB0. Timer0. Częstotliwościomierz
|
|
|
PAWEŁ BORKOWSKI
|
Najbliższe 2 części kursu posłużą nam do skonstruowania
urządzenia zliczającego liczbę wystąpienia zjawiska
w danym czasie. Oczywiście chodzi o zjawiska, których
czas trwania liczony jest w mili- i mikrosekundach, co uniemożliwia
bezpośrednią obserwację. Zakładając że zjawisko
występuje w sposób okresowy, będziemy dążyć do budowy
częstotliwościomierza. Czym będą różniły się nasze projekty
od wielu podobnych funkcjonujących w literaturze? Nasz
częstotliwościomierz zostanie zbudowany bez konieczności
użycia dodatkowego oprzyrządowania, a wszystkie jego
funkcje zostaną zaimplementowane w sposób programowy.
Przy tym, jak się okaże, jego dokładność będzie zaskakująco
duża. Wyniki będą wyświetlane na alfanumerycznym wyświetlaczu
LCD. Z powyższego wynika, że w pierwszej kolejności
musimy nauczyć się obsługiwać wyświetlacz LCD.
Schemat prezentujący najprostsze podłączenie alfanumerycznego
wyświetlacza LCD do mikrokontrolera PIC16F84A
przedstawia rys. 1.
Linia V0 służy do nastawy kontrastu. Jej bezpośrednie
podłączenie do masy wymusza wyświetlanie znaków maksymalnie
nasyconych czernią. Natomiast linia RW służy do
konfigurowania kierunku przepływu danych. Wysoki stan logiczny
na linii RW umożliwia odczytanie danych z pamięci
wyświetlacza LCD, zaś wyzerowanie linii pozwala tę pamięć
zapisywać. Ponieważ tylko ten drugi rodzaj obsługi pamięci
wyświetlacza LCD będzie nas interesował, linię RW podłączyliśmy
do masy.
Kompilator mikroC PRO for PIC został wyposażony
w bibliotekę obsługi alfanumerycznych wyświetlaczy LCD, co
znacznie ułatwia proces programowania. Aby móc skorzystać
z funkcji biblioteki, musimy przede wszystkim zdefiniować połączenie
wyświetlacza z mikrokontrolerem.
//połączenia LCD z mikrokontrolerem
sbit LCD_RS at RB4_bit;
sbit LCD_EN at RB5_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
//konfiguracja portu obsługującego LCD
sbit LCD_RS_Direction at TRISB4_bit;
s[...]
|
|
|
|
Mobile Safety System for the Blind
|
|
|
KRZYSZTOF BOROŃ WOJCIECH GELMUDA ANDRZEJ KOS
|
There are many devices on the market that help the visual
impaired people to walk in unknown urban environment [1- 4].
Numerous research and tests have been carried out in Special
Educational Centre for Blind and Partially Sighted Children in
Kraków. The results show there is still one major problem that
needs to be solved. This problem concerns holes and road excavations
in the ground and small yet very dangerous hanging
obstacles which a blind person can encounter - Fig. 1.
A device has to be designed to help the visual impaired people
deal with the types of dangerous situations mentioned above There are devices designed especially for the visual impaired
people that inform them about some obstacles and
free space; for instance one device can inform if a seat in
a train is occupied or not or if an elevator door is open or
not. However, there is no such a device that could inform
about holes and road excavations, especially the ones that
have recently occurred on a daily road from a blind person’s
home to their work place, damages in stairs or open space
between an edge of a train platform and tracks [5]. Holes
and road excavations are usually marked but it is very hard
for blind people to spot and detect them. That is why any
road hole is a serious danger for them. With some help of
an electronic device for blind people or just a simple white
stick, a blind person is able to determine if there is a hole
ahead. But the problem is th[...]
|
|
|
|
Model of high rate reactive pulsed magnetron sputtering
|
|
|
KATARZYNA TADASZAK WITOLD M. POSADOWSKI
|
Several models have been developed to describe reactive
magnetron sputtering process. Most of them were based on
the classical model derived by Berg et al. [1], which is mainly
focused on the target surface condition influence. However,
the deposition mechanism is complicated and could not be
precisely described with simple analysis of sputtered surface.
It requires also studies of collecting area state, plasma properties,
particle transport, etc.
The deposition of aluminium oxide can be successfully
used to illustrate the sputtering process. Aluminium and aluminium
oxide differs strongly in regard to emission and sputtering
properties. The sputtering yield of Al2O3 is lower than Al,
thus with progressing oxidation of the target deposition rate
is decreasing. On the other hand, aluminium oxide has two
times higher ion induced secondary electron emission coefficient,
what indicates increase of emission and changes of
plasma impedance. Those properties make aluminium an
ideal material for illustrating mechanisms which influence on
reactive sputtering process.
Experimental details
With reference to the Berg’s model, high rate reactive pulsed
magnetron sputtering of the aluminium target in argon and
oxygen gas mixtures has been studied. High quality dielectric
layers were deposited with use of the DPS pulsed power
supply and the special construction of magnetron source [2,
3]. The magnetron source WMK-50 equipped with a 50 mm
diameter and 7 mm thick aluminium target was used during
the experiments. Substrate to target distance was dS-T=
75 mm. The available maximum target power density was
about 1000 W/cm2 (however not used in this experiment).
The process has been performed in a vacuum system equipped
with a rotary and diffusion pump with a pumping speed
of 2000 l/s. The final pressure of the deposition chamber
was about 2 mPa. All experiments were performed in atmosphere
of argon and oxygen gas mixture with total press[...]
|
|
|
|
Modeling the ballistic and tunnel source-drain currents in Silicon Nanowire MOSFETs
|
|
|
ANNA SAWICKA BOGDAN MAJKUSIAK TATSUHIRO NUMATA SHIGEYASU UNO GENNADY MILNIKOV NOBUYA MORI
|
Silicon nanowire MOSFETs due to excellent controllability of
the channel by the gate electrode are promising as next generation
device structures for further CMOS scaling. Nanowire
MOSFETs have been extensively investigated and both
compact and numerical models of ballistic current have been
reported [1, 2]. However, modelling of only the ballistic component
of the current is not sufficient. If the channel is short
enough, the tunnel component becomes significant.
Silicon nanowire MOSFET structure
We assume a simple square cross section Si nanowire
N-MOSFET structure (Fig. 1) with an intrinsic channel, midgap
gate and SiO2 as a gate dielectric, source and drain doping
concentration ND = 10 20 cm-3.
Due to strong quantum confinement in a very narrow
(3…5 nm) nanowire cross section, transport occurs along onedimensional
subbands. The 1D subbands profiles for all six silicon
energy valleys and for the lowest quantum numbers were
extracted from results of the NEGF simulations and the transfer
matrix (TM) method was applied to calculate the source-drain
current. Ballistic current was calculated by integrating current
contributions for energies above the top of the potential bar[...]
|
|
|
|
Modeling the charge trapping effect in high-K gate stacks on the tunnel current
|
|
|
ANDRZEJ MAZURAK BOGDAN MAJKUSIAK
|
High-K dielectrics play a key role in the present MOS technology
scaling. One of the obstacles to overcome scaling
barriers is improvement of the electrical quality of the substrate-
oxide interface and dielectric quality in respect to the
space distributed charges. Electrically active traps influence
significantly the device electrical characteristics. In this
work we discuss an influence of distributed charges in the
gate stack on the current-voltage characteristics of the MOS
structure.
Quantum well trap model
A charge trap is modeled as a quantum well of thickness in the
range of a few angstroms (Fig. 1). Position of the Fermi level
in the quantum well in respect to the substrate corresponds
to charging of a trap due to the tunneling and the thermal recombination-
generation processes. The tunneling probability
is calculated with the use of the transfer matrix method with
inclusion of carrier scattering in the well [1]. The scattering
rate parameter moderates the impact of the trap on the current
transport.
High-K gate stack with charges trapped
model
The modeled gate stack consists of the interfacial SiO2 layer
and a high-K dielectric layer. The high-K layer is divided
into sections. The trapped charge is modeled as effective
charge located at the interlayer planes. For tunneling probability
through the multilayer g[...]
|
|
|
|
Oscylator harmoniczny sterowany cyfrowo projektowany w oparciu o transmitancje wzmacniaczy operacyjnych
|
|
|
MIROSŁAW PŁAZA
|
Oscylatory są układami elektronicznymi wytwarzającymi
przebiegi elektryczne o określonym kształcie i niegasnące
z upływem czasu. Są one niezbędnymi podzespołami niemal
każdego bardziej złożonego urządzenia elektronicznego, ponieważ
poza oczywistymi przypadkami generatorów sygnałowych,
funkcyjnych lub impulsowych, zastosowanie źródła
drgań okresowych konieczne jest prawie w każdym przyrządzie
działającym cyklicznie, inicjującym pomiary lub procesy
technologiczne oraz którego działanie wymaga okresowej
zmiany stanów [1, 2]. Ze względu na bardzo szeroki obszar
możliwych zastosowań obwodów oscylatorów problematyka
ta jest fundamentalną sprawą w rozwoju wielu gałęzi współczesnej
nauki i techniki. Publikowane w ostatnich latach prace
z zakresu projektowania i analizy obwodów oscylatorów
[3-5] skupiają się głównie na eliminacji biernych elementów
zewnętrznych oraz zastępowaniu ich inercyjnymi elementami
aktywnymi. Zastąpienie np. zewnętrznych biernych pojemności
wzmacniaczami operacyjnymi wpływa na poszerzenie
pasma przenoszenia sygnałów wyjściowych [6]. Zagadnienie
eliminacji biernych elementów zewnętrznych oraz zastępowanie
ich elementami aktywnymi jest bardzo często poruszane
również w kontekście innych niż oscylatory układów elektronicznych.
Główny kierunek jaki należy tu wyróżnić [7-9] dotyczy
projektowania i analizy układów filtrów aktywnych. W niektórych
pracach na ten temat projektowane filtry uzupełniane
są o układy sterujące, dzięki którym uzyskuje się możliwości
cyfrowego strojenia ich parametrów (np. wartości częstotliwości
granicznej lub wartości wzmocnienia). W pracach [10, 11]
zmiany parametrów oscylatorów realizowane były poprzez
odpowiednie zmiany wartości stosowanych elementów biernych
(rezystorów). Bieżąca literatura jedynie w niewielu przypadkach
[12] wspomina zagadnienie, jakim jest możliwość cyfrowego
przestrajania parametrów oscylatorów. Uzupełniając
układy os[...]
|
|
|
|
Properties of thick-film photoimageable inks for LTCC substrates
|
|
|
PIOTR MARKOWSKI MAŁGORZATA JAKUBOWSKA ELŻBIETA ZWIERKOWSKA MARTA DANIELKIEWICZ KLAUS JURGEN WOLTER MARCO LUNIAK
|
Miniaturization of electronic circuits is strongly associated with
miniaturization of conductive paths and pads. It also refers
to thick-film technology. Fabrication of details narrower than
150 μm by using of standard screen-printing is very difficult
task. There are few more precise techniques - for example
photoimageable inks method [1, 2]. It enables to create even
several-micrometers wide paths.
The inks prepared at Institute of Electronic Materials Technology
(ITME) were tested.
The compatibility between such inks and LTCC (Low Temperature
Cofired Ceramics) substrates was especially an object
of interest. The investigations were performed at Wrocław
University of Technology, Warsaw University of Technology
or Dresden Technical University. The path’s resolution, inks
shrinkage as well as chosen electrical and mechanical properties
(electrical resistivity, solderability, adhesion, shear resistance)
were determined.
Fabrication
The photoimageable films were made using standard screen-printing
combined with photolithography [3]. A special ink was screen-
printed onto the substrate (Fig. 1a). The investigated pastes
had good UV-resistance and using of UV-filters was unnecessary
[4]. However, they need large amount of radiation during exposing.
A proper photomask caused that only selected areas of ink
were polymerized by UV light (Fig. 1b). The Hibridas Exposure
Unit MA-4K were used. Remaining areas stayed unpolymerized
and it was possible to remove them in the next technological step
- spraying with proper developing solution (Fig. 1c). The Hibridas
Developer Unit SC-4K and ethanolamine solution were used. As
a result pattern from the photomask was transferred onto the substrate.
The last technological step was firing of achieved layer in
t[...]
|
|
|
|
Sensor for the measurement of combustion heat
|
|
|
ZBIGNIEW MAGOŃSKI
|
Fluid fuels are widely used for motor powering, heating and
cooking. Possibility of verification the quality of fuels is of paramount
importance because fuel quality directly influences
on consumption, and this way on customer charges. On the
other hand, evaluation the quality of fuels, especially fuel heat
energy, is a long time consuming process, which can be completed
at laboratory site with a specific equipment. Proposed
sensor can be a foundation for construction of simple portable
instrument, which can be considered as an alternative to the
expensive and bulky bomb calorimeter.
Method of measurement
The principle of measurement is explained in Fig. 1. A small
volume stable flame is maintained between two ceramic plates,
which temperature is being controlled by two thin film platinum
resistors deposited on the both ceramic plates. These
resistors serve as heaters and temperature sensors.
The resistors are connected to electronic circuitry, which
maintains a constant temperature of the both ceramic plates
regardless of external or internal conditions. It is also assumed
that the both ceramic plates display sufficiently high thermal
conductivity that the same single value of temperature
can be considered for each small portion of both ceramic plates.
The temperature of both ceramic plates is maintained at
constant temperature level above 800°C. High temperature of
combustion zone is essential for performance, because the
flame is not quenched in the vicinity of hot ceramic plates and
thus a stable burning process can be maintained very close
to the ceramic plates, so, the heat exchange factor can be
improved.
As the additional amount of fuel enters the combustion
zone, and is being burned additional amount of heat is produced.
That heat flux mostly in form of infrared radiation is
absorbed by the ceramic plates.
In response, in order to maintain the constant temperature
of ceramic plates, the control circuit decreases t[...]
|
|
|
|
Simulation and modelling of planar EMI/RFI Filters
|
|
|
Piotr RYDLICHOWSKI WOJCIECH BANDURSKI
|
In th e paper discussion and analysis of the new prototypes of
the planar lowpass power filters is presented. Basic structure
is shown in Fig. 1 (not in scale). In [2] variations of considered
basic structure are proposed and analyzed. Presented in [2]
alternative structures were expected to provide information
needed for accurate and efficient numerical and analytical
simulation.
Target application of discussed structures is suppression
of RF-EMI interference in power electronic devices. Such interferences
are found primarily in integrated high power converters
(power densities 13 W/cm3 and above). Interferences
are also induced by electromagnetic coupling between electronic
devices during switching and by inductance and capacitance
in electronic devices and in module package. Popular
technologies used in aerospace industry prefer filters structures
that are integrated (for convenience) with coaxial cables.
Together with new devices and technologies a need has occur
to design new, small, planar lowpass filter for Integrated Power
Electronic modules (IPEMs). Such modules with kilowatt
powers and high power densities can emit significant RF-EMI
interferences. Proposed filters for radio frequency (RF) modules
should satisfy three main prerequisites: 1) because structure
should be physically small the speed of electromagnetic
wave must be reduced to fraction of its free-space velocity
value, 2) structure should be electrically and mechanically
able to handle power from 1 kW to 10 kW at 300 V to 500 V
and 30 A, 3) filter cut-off slope should be as steep as possible
(e.g., > 40 dB/decade).
Prototype structure described in [1] satisfies specified above
requirements. Manufacturing technology of this kind of filters
and experimental measurements of the amplitude characteristics
are presented and discussed. Amplitude characteristics
a[...]
|
|
|
|
State minimization by means of incompatibility graph coloring
|
|
|
ROBERT CZERWIŃSKI DARIUSZ KANIA
|
The mathematical model of a sequential circuit is a Finite
State Machine (FSM). A Finite State Machine is generally
defined as a five-tuple: {X, Y, S, δ, λ}, where: X is a finite
input alphabet, Y is a finite output alphabet, S is a finite set
of states, δ is the transition function, and λ is the output
function. The transition function of an FSM determines the
next state of the automaton (S+), and the output function
determines outputs. The structure of the FSM is presented
in Fig. 1.
Internal states of an FSM are given mostly symbolic values.
FSMs can be represented by a State Transition Table
(STT). Every row of an STT corresponds to a transition between
two states of the machine. The rows are divided into
four columns corresponding to the primary inputs, present
states, next states, and primary outputs (the kiss format). The
rows of a STT are called symbolic implicants. An example of
a state transition graph, with a corresponding STT, is presented
in Fig. 2.
Fig. 1. The structure of an FSM
Rys. 1. Schemat blokowy układu sekwencyjnego
Fig. 2. A state transition graph and a corresponding STT
Rys. 2. Graf przejść automatu z odpowiadającą mu tablicą
przejść-wyjść
X Y
S
Clk
S+
s1
1/01
s2
0/10
0/11
1/00
1 s1 s1 01
0 s1 s2 11
0 s2 s2 10
1 s2 s1 00
S+ X S Y
Podsumowanie
W artykule przedstawiono układ sterowanego cyfrowo aktywnego
oscylatora harmonicznego, w którym jako elementy
inercyjne wykorzystano dwa popularne wzmacniacze operacyjne
TL081. Badania prezentowane w pracy motywowane
były potrzebą poszukiwania rozwiązań układowych dla
tego typu obwodów. Zaletą prezentowanego w pracy obwodu
jest zapewnienie możliwości cyfrowego przestrajania
jego parametrów (zarówno częstotliwości jak i amplitudy).
Układy projektowane w oparciu o prezentowaną w pracy
koncepcję teoretyczną m[...]
|
|
|
|
Surface morphology study and dielectric properties of polyesterimide nanocomposite
|
|
|
BARBARA GÓRNICKA ANDRZEJ SIKORA DAMIAN WOJCIESZAK
|
It is now well known that nano-structuring of composites affect
significantly on their dielectric properties as well the surface
morphology [1-6]. On the other hand, the new generation of
dielectrics, i.e. polymers modified with nanofillers, due to their
special structure may influence on a better understanding of
the phenomena that appear in dielectrics [1].
The polyesterimide impregnating varnish (T) have been
modified by incorporation of hydrophilic fumed nanosilica
(SiO2) at a low loading (1.5% by weight) using our special
method. The influence of nanostructuring of composites on
the thermally stimulated depolarization currents, temperature
characteristic of tan δ and partial discharges resistance as
well the nanoscale surface morphology were investigated.
Experimental
The thermally stimulated depolarization current (TSDC), partial
discharge (PD) resistance, temperature characteristic of
tan δ and surface morphology have been investigated for both
pure (T) and nanofilled (T+ SiO2) varnishes.
In the thermally stimulated depolarization current (TSDC)
investigation at 120oC, a static voltage 100 V and 200 V was
applied to a sample for a time 40 minutes and then temperature
was decreased for a time 20 min to ambient temperature.
The voltage was switched off and the sample was
shortcircuited for a time 30 min to eliminate the rapid space
charge relaxation and stabilize the sample. Then during a linear
temperature increase 2 oC/min, the return to equilibrium
of the previously oriented charges generated a depolarization
current which was recorded, as a function of temperature, with
a electrometer (Keithley 6517[...]
|
|
|
|
Syntezer sygnałów złożonych na bazie układów FPGA
|
|
|
MARIUSZ ŁUSZCZYK
|
Jednym z technicznych kierunków rozwoju urządzeń radarowych
jest cyfryzacja toru nadawczo-odbiorczego przejawiająca
się w stosowaniu półprzewodnikowych modułów nadawczo-
odbiorczych pracujących z cyfrowo generowanymi
sygnałami złożonymi, cyfrowymi układami kompresji impulsów
(w przypadku urządzeń pracujących z sygnałami impulsowymi)
oraz cyfrowymi układami sterowania i korekcji wiązki antenowej
w przypadku platform lotniczych [11]. Zalety cyfryzacji
wybranych elementów toru nadawczo-odbiorczego to przede
wszystkim większa niezawodność układów, większa powtarzalność
charakterystyk elektrycznych, mniejsza podatność
na zakłócenia, możliwości kształtowania i korekcji charakterystyk
fazowych całego toru oraz łatwiejszy sposób zapewnienia
zgodności interfejsów w przypadku transmisji sygnałów
cyfrowych. Przetwarzanie sygnałów w technice SAR wymaga
bardzo wysokiej stabilności krótkookresowej sygnałów i zapewnienia
pełnej koherencji. Realizacja tych wymagań jest
łatwiejsza do realizacji w układach cyfrowej syntezy sygnałów
połączonych i synchronizowanych z układami czasosteru.
Ze względu na postęp w dziedzinie elektroniki cyfrowej
zwłaszcza w zakresie układów programowalnych, układów
pamięci oraz układów konwersji cyfrowo-analogowej i analogowo-
cyfrowej dokonuje się przełom w projektowaniu układów
syntezerów cyfrowych oraz układów filtracji dopasowanej
i detekcji fazy [3].
Najczęściej wykorzystywanym sygnałem w urządzeniach
radarowych, w tym także w urządzeniach typu SAR jest sygnał
z wewnątrzimpulsową modulacją częstotliwości (LFM).
Sygnał LFM ma kwadratową charakterystykę fazową oraz
liniową (w funkcji czasu) charakterystykę modulacyjną. Podstawowym
parametrem sygnału jest jego baza, którą wyznacza
się jako iloczyn szerokość widma sygnału (dewiacja) oraz
czasu trwania impulsu. Baza łączy ze sobą dwa podstawowe
parametry sygnału, ale należy pamiętać, że energia sygnału
uzależniona jest od czasu trwania sygnału, zaś rozdzielczość
[...]
|
|
|
|
System odtwarzania cyfrowych sygnałów elektroakustycznych
|
|
|
ARKADIUSZ HULEWICZ MARCIN KUPSIK
|
W dobie intensywnego rozwoju technologicznego oraz wzrastającej
liczby systemów pomiarowych, w których nośnikiem
danych jest dźwięk, ważną rolę w ocenie pozyskanych sygnałów
odgrywa sposób ich archiwizacji oraz odtwarzania.
Z opracowanych dotąd metod umożliwiających archiwizację
i odtwarzanie sygnałów dźwiękowych, najczęściej wykorzystywana
była metoda oparta na przetwarzaniu sygnałów
analogowych [16]. W sygnałach tych analizie poddawano
parametry magnetyczne, elektryczne lub mechaniczne, które
po odpowiednim przetworzeniu umożliwiały odtwarzanie
wybranych dźwięków. Systemy te charakteryzowały się wysokim
poziomem zakłóceń i szumów oraz wysoką wrażliwością
nośników danych, które z upływem czasu ulegały degradacji.
Właściwości te spowodowały, że analogowe systemy archiwizacji
dźwięku zostały zastąpione nośnikami cyfrowymi.
Rozwój cyfrowych systemów przetwarzania danych
znacznie poprawił jakość rejestracji i archiwizacji sygnałów
dźwiękowych [13, 14, 15]. Cyfrowy zapis dźwięku zdominował
przemysł fonograficzny po wprowadzeniu płyt kompaktowych,
co miało miejsce w latach osiemdziesiątych XX wieku.
Technologia cyfrowa charakteryzuje się wysoką odpornością
na zakłócenia i szumy oraz dużą wytrzymałością nośników,
co doprowadziło do zaniechania zapisu dźwięku dotychczas
wykorzystywanymi metodami analogowymi [3, 5, 6].
Przedstawione w artykule metody cyfrowej rejestracji
i archiwizacji sygnałów dźwiękowych zostały wykorzystane
w opracowanym przetworniku, umożliwiającym odtworzenie
zarejestrowanych danych z określoną dokładnością. Opracowany
przetwornik pozwala na współpracę z komputerem,
a charakteryzuje go wysoka jakość generowanego dźwięku.
W ramach przeprowadzonych badań zweryfikowano parametry
zbudowanego przetwornika oraz porównano je z parametrami
urządzeń dostępnych na rynku. Podczas badań wykorzystano
program RightMark Audio Analyzer 6.2.3.
Cyfrowe przetwarzanie sygnałów
dźwiękowych
Z przetwarzaniem analogowo-cyfrowym zw[...]
|
|
|
|
System setup and software for impedance spectroscopy measurements
|
|
|
TOMASZ PIASECKI MATEUSZ WROŃSKI MARCIN DUDEK KAROL NITSCH
|
The impedance spectroscopy (IS) is one of the methods for
investigation of electric material properties such as electric
properties, the corrosion, performance of passive electronic
devices or gathering information about the structural properties
of materials or complex composites [1-3]. IS relies on the
measurement of impedance performed in the frequency range
of several orders of magnitude. Impedance is measured by
applying small electromagnetic signal to the object under investigation
and measuring the response. If the excitation is
sinusoidal and object is linear the response is also sinusoidal.
The impedance Z is the complex number representing both
magnitude and phase shift of the response.
(1)
where U and I are the magnitudes of voltage and current, jωφU,
jωφI are the phases of voltage and current and ω is the radial
frequency.
The factors which have to be taken under account during
the measurement are the proper definition of sample’s shape
and stable electrical contacts as the measurements may take
long time. The range of frequencies used is also important. In
some cases it has to be very wide to allow to detect all phenomena
occurring in the sample.
System setup
To fulfill the requirement of the wide range of possible frequencies
at which the measurements are performed the authors
built impedance measurement system based on two impedance
analyzers: Agilent 4294A and Solartron FRA 1260.
Agilent 4294A is a fast, precise, high frequency impedance
analyzer which is able to measure impedance from 40 Hz to
110 MHz. While on the other hand[...]
|
|
|
|
Temperature control for disposable lab-on-chip microsystems
|
|
|
JERZY KALENIK KONRAD KIEŁBASIŃSKI KRYSTIAN KRÓL
|
The rapid development of lab-on-chip microsystems for chemical
or biochemical analysis have taken place for last years.
Many of analytical reactions should be carried out at defined
temperature so they need temperature stabilization. The microsystems
for biochemical analysis of human fluids should
be disinfected thoroughly or used only once. The disposable
parts of microsystem need to be very simple, cheap and
environment friendly because of the large number of these
components applied and disposed, for example microsystems
for dialysis monitoring.
The aim of this work was to elaborate very simple, cheap
and environment friendly system for temperature stabilization
of disposable postdialysate fluids analysis microsystem.
Temperature measurement methode
for lab-on-chip application
In typical temperature control applications two separate elements
are used - heater and temperature sensor. The disadvantage
of such approach in microsystem technology is necessity
of applying tw[...]
|
|
|
|
The analysis of detection possibility of optical radiation pulse with thermal method
|
|
|
ZBIGNIEW SUSZYŃSKI MICHAŁ BEDNAREK
|
The purpose of active thermography is to detect thermal heterogeneities
or excitation energy distribution by measuring
the temperature disturbance at the surface of the examined
object in frequency or time domain. The variable component
of temperature for the harmonic excitation can be obtained as
a product of the power of excitation and thermal impedance
of the object (1):
T(ω) = P(ω) · Z(ω) (1)
In the case of thermally heterogeneous object, excited by
a power P(ω), with thermal properties represented by its thermal
diffusivity α and thermal effusivity ε, reaches at the surface
temperature described by the function T(ω). The values
of temperature response (amplitude and phase) for frequencies
of excitation spectrum carry information about the type
and location of the thermal heterogeneities.
Reconstructing the thermal properties distribution of the
object basing on the temperature response measurements
is possible if the function P(ω) describing the power of the
excitation energy is known. In the general case the optical
excitation is characterized by varied optical and frequency
spectra. Spectral character of thermal impedance causes
that the temperature response, and hence the temperature
contrast of thermal heterogeneity, significantly depend on the
frequency spectrum of the excitation pulse. It would be ideal
if the excitation spectrum was correlated with the thermal impedance
spectrum, which can be determined if the thermal
properties of the object are known. In active thermography
the excitation energy is usually performed by using optical
radiation. That is why the frequency spectrum of excitation
can be optimized by modulating its intensity in time. This can
be realized by using choppers (mechanical modulation) or
by changing the supply current (semiconductor lasers, filament
lamps, etc.). In case of pulsed sources (flashlight, laser
pulse) the excitation spectrum can be[...]
|
|
|
|
The MPW service development
|
|
|
DARIUSZ OBRĘBSKI KRZYSZTOF KUCHARSKI DANIEL TOMASZEWSKI HELENA KŁOS
|
The entire work spent for MPW service development can be
split into three main parts related to three groups of activities:
process characterization, process design kit (PDK) development
and logistics issues. The process characterization part,
which is the starting point, focuses on measurements of process
parameters (e.g. sheet resistance of interconnect layers)
as well as parameters of all silicon devices available (e.g. models
of all transistor types). Special test structures, dedicated
for given sets of parameters are also designed and manufactured
at this stage. The second set of activities focuses on development
of all necessary data files, as well as programs and
procedures which are essential to run chosen CAD tools. In
our case we decided to develop ITE Process Design Kit (IDK)
for CAD tools from Cadence Design Systems (CDS), as the
most popular one in academia community. The only exception
is synthesis, which has been implemented using Synopsys
DC. The aim of last group of activities was to establish all mechanisms
which are needed to run MPW service.
The C3P1M2 CMOS process
The basis of ITE MPW service is ITE’s proprietary CMOS process,
named C3P1M2, which was developed for the purpose
of ASICs manufacturing. Its key features are: single p-well,
one polysilicon layer, two metalization layers. The standard
process requires 12 levels of photolithography. Main structural
parameters of C3P1M2 process are collected in Table 1.
Process characterization
The prerequisites for PDK development are parameters of
technology layers specific for given process and models of
silicon devices available. Process characterization stage is
devoted to acquiring these data.
Measurement tools
The Keithley system 93 I-V, controlled by METRICS [4] software
was the essential tool used for silicon devices characterization.
To enable the semi-automatic measurements, it
was combined with ELECT‑2002 [5] system, which controls
mea[...]
|
|
|
|
Thermal stability of SiC MOS transistors
|
|
|
WITOLD J. STEPOWICZ
|
Progress in the improvement of technical data of SiC devices
is observable, however it is under expectation arising from
theoretical considerations. Especially it concerns the maximum
(allowable) junction temperature, what results, among
other things, from difficulties to construct reliable metal - semiconductor
contacts and reliable cases for SiC devices provided
for operation, after some forecasts, up to 800oC. It was
demonstrated [1] that for SiC MOS transistors and other SiC
devices an additional thermal limitation has to be taken into
consideration. This limitation results from self-heating phenomenon
included in the dc model of the SiC MOS transistor.
In [2] the same limitation was described for the silicon MOS
transistor.
The aim of this paper is to discuss the above-mentioned
additional limitation of the temperature operation range of the
SiC MOS transistor, resulting from its thermal stability, when
the considered device operating in the linear region of its dc
characteristics is supplied from the constant current source.
S-type And N-type DC characteristics
of semiconductor devices
As known, the dc characteristics i (u) of some semiconductor
devices can have their shape of the S-type or N-type as
shown in Fig. 1. It can be caused by many electrical and thermal
phenomena taken into account when these characteristics
are derived. One of this phenomena is self-heating which
causes that the junction (inner) temperature of a device differs
from the ambient temperature due electrical power dissipated
and non-ideal conditions of removing the heat from the device
to surroundings. The dc characteristics with self-heating taken
into consideration are oft called as the non-isothermal ones.
For any device with the dc non-isothermal charac[...]
|
|
|
|
Veterinary and medical lab-on-a-chip - based point of care diagnostic devices with optical detection
|
|
|
RAFAŁ WALCZAK
|
The decrease of world microsystem (MEMS) market observed
in years 2008 and 2009 and caused by world crisis has been
minimized due to rapid growth of microfluidical devices market
for in vitro diagnostic (IVD). Microfluidical IVD is usually realized
by application of lab-on-chips (LOCs) and point-of-care
devices. According to Yole Developement’s recent roadmap of
world LOC market for medical and life sciences applications,
IVD LOC market was estimated to reach about 1 B$ in 2010,
whereas in 2012 it will be doubled to the level of 2 B$ [1]. Total
number of soled units of LOC in year 2010 was estimated to
be about 177 millions whereas in 2015 it will be over 780 millions
units. This 4-times increase of number of the fabricated
and soled LOC units, as well as almost 20% of average annual
growth rate of the market, cause that LOC IVD market is
one of the leading application fields of global MEMS market.
Value of IVD LOC world market in 2015 will be comparable
to “killer" products of MEMS industry - miniaturized pressure
sensors, gyroscopes or ink jet heads. It is predicted that IVD
LOC will be a driving force of analytical microsystem market
in the next two decades. Deeper analyze of this market leads
to the conclusion that three main fields of applications dominate
- human point-of-care devices, labs-on-chip dedicated
for PCR and capillary electrophoresis for both - medical and
veterinary - applications. One of the important issues involved
in successful application of LOC in IVD is detection method
and instrumentation compatible in dimensions and costs with
LOC.
In this paper a brief review on miniaturized fluorometric
instrumentation co-working with LOC will be discussed. An
idea and technical realization of novel fluorometric readout
instrumentation will be presented. Finally, brief review of complex
LOC-based instruments developed under 6. FP OPTOALBCARD,
7. FP LABONFOIL as well as Polish MNS-DIAG/
APOZAR projec[...]
|
|
|
|
Warstwy zabezpieczające ogniw słonecznych nanoszone w niskiej temparaturze
|
|
|
KAZIMIERZ DRABCZYK PIOTR PANEK
|
Przyrządy półprzewodnikowe, jakimi są ogniwa fotowoltaiczne,
muszą być zabezpieczone przed szkodliwym wpływem
czynników zewnętrznych. Stosuje się do tego celu różnego
rodzaju warstwy zabezpieczające. Obecnie najpopularniejsze
warstwy zabezpieczające to wszelkiego typu polimery.
Najczęściej stosuje się octan polietylenowo winylowy EVA
(Ethylene-Vinyl-Acetate). Ogniwa słoneczne zabezpiecza
się w postaci modułów, które powstają w procesie laminacji
w podwyższonej temperaturze i w obecności próżni. Innym
ważnym elementem modułu jest przednia szyba zabezpieczająca
moduł mechanicznie. Szyba taka jest bardzo odporna
mechanicznie (szkło hartowane), ale jednocześnie jest
bardzo ciężka. Z tego powodu czasami jest ona eliminowana
z modułu fotowoltaicznego. Zastępowana jest innym
materiałem, na przykład blachą aluminiową na tylnej części
modułu.
Eksperyment
Wszystkie badania dotyczące przedsta-wionych sposobów
laminacji niskotempera-turowej przeprowadzono w Laboratorium
Fotowoltaicznym Instytutu Metalurgii i Inżynierii Materiałowej
PAN (LF IMIM PAN) w Kozach. Ogniwo referencyjne stosowane
do pomiarów charakterystyk prądowo-napięciowych
skalibrowano w Institute für Solarenergieforschung w Hameln
Emmerthal (Niemcy).
Typowy proces laminacji ogniw słonecznych składa się z 7
etapów, zależnych od stosowanej technologii, sprzętu oraz
użytych materiałów. Natomiast prowadzone badania składały
się z 4 zasadniczych kroków pokazanych na rys. 1.
Materiałem bazowym użytym do badań w niniejszej pracy
były:
płyty [...]
|
|
|
|
Wpływ domieszkowania Tb na zwilżalność i wolną energię powierzchniową cienkich warstw TiO2
|
|
|
DAMIAN WOJCIESZAK DANUTA KACZMAREK JAROSŁAW DOMARADZKI EUGENIUSZ PROCIÓW FRANK PLACIDO JOHN KAVANAGH MICHAŁ MAZUR
|
Dynamiczny rozwój metod fizycznego osadzania PVD (Physical
Vapour Deposition) związany jest z rosnącym w ostatnich
latach zapotrzebowaniem na nanokrystaliczne powłoki,
które posiadają nowe i odmienne właściwości w porównaniu
do standardowych powłok. Szeroko prezentowane w literaturze
przedmiotu przykłady możliwości zastosowania tego typu
powłok dotyczą głównie takich tlenków metali jak TiO2 [1-10],
SnO2 [11], czy ZnO [12]. Materiały te są dobrymi kandydatami
do wytwarzania tzw. powłok funkcjonalnych, których właściwości
mogą być modyfikowane, między innymi, przez selektywne
domieszkowanie [1, 10, 11]. Z punktu widzenia zastosowań
pożądane są powłoki o wysokiej przezroczystości
[1, 8], wysokiej aktywności fotokatalitycznej [2, 6], podwyższonej
twardości [3, 8], czy też o odpowiednich właściwości elektrycznych
[3, 11, 12]. Oprócz tego istnieje zapotrzebowanie na
powłoki o określonej zwilżalności powierzchni, czyli tzw. powłoki
hydrofilowe oraz hydrofobowe [7, 9]. Są to warstwy o odpowiednio
wysokim lub niskim stopniu zwilżalności powierzchni
przez wodę. Zwłaszcza wytwarzanie warstw na bazie tego
samego materiału, które mają różny stopień zwilżalności jest
atrakcyjne z punktu widzenia zastosowań w przemyśle.
W pracy przedstawiono analizę wyników pomiarów zwilżalności
nanokrystalicznych cienkich warstw TiO2. Właściwości
matrycy były modyfikowane przez domieszkowanie terbem.
Elektronika 3/2011 77
Zwilżalność powierzchni cienkich warstw TiO2 badano w celu
określenia wpływu domieszkowania terbem na termodynamiczne
właściwości powierzchni warstw. Dwutlenek tytanu
został wybrany jako matryca z uwagi na wysoki stopień przezroczystości
w zakresie widzialnych fal świetlnych, odmienne
właściwości w zależności od typu struktury krystalicznej,
nietoksyczność i wysoki st[...]
|
|
|
|
Zmiany w modelach i technologiach informacyjnych w dobie Web 2.0 i Web 3.0
|
|
|
JOLANTA BRZOSTEK-PAWŁOWSKA
|
Zapoczątkowana przed kilku laty pojawieniem się pierwszych
portali społecznościowych i udostępnianych na nich aplikacji,
dziś zwanych aplikacjami społecznymi lub technologiami Web
2.0, rewolucja informacyjna w krótkim czasie zmieniła model informacyjny
Internetu z modelu statycznych stron WWW niosących
informacje na model interaktywnego udziału użytkowników
tworzących strumienie informacji w czasie rzeczywistym. Web
czasu rzeczywistego jest nową formą komunikacji zwiększającej
o rząd szybkość informacji. Technologie Web 2.0 i szybkość
komunikacji wpłynęły na zmiany w modelach informacyjnych realizowanych
przez systemy, ponieważ zmieniły się postawy, potrzeby
i oczekiwania użytkowników. Zjawisko społecznej wiedzy
spowodowało inne podejście do zarządzania wiedzą - jej gromadzenia
i dystrybucji. Dziś informacja adekwatna do potrzeb
musi natychmiast dotrzeć tam, gdzie znajduje się użytkownik,
przede wszystkim na stanowisko pracy, stacjonarne lub mobilne,
aby zwiększyć wydajność pracownika. Aby informacja była
najbardziej wartościowa i najlepiej dostosowana do kontekstu,
w jakim pojawiła się jej potrzeba, to z jednej strony mechanizmy
wyszukiwania muszą obejmować jak najwięcej źródeł informacji,
z drugiej strony informacje muszą być trafnie, wieloaspektowo
opisane. Coraz doskonalsze technologie Web 3.0 mają
za zadanie dostarczać wiedzę inteligentnie, czerpiąc ją również
ze źródeł społecznych. Inteligentna dystrybucja wiedzy bazuje
m.in. na szczegółowym opisie semantycznym gromadzonych
informacji, jak również na wnikliwej analizie danych otrzymywanych
od użytkownika, czemu służą tzw. semantyka Web 3.0, jak
i mechanizmy sztucznej inteligencji. W artykule przedstawiono
wpływ Web 2.0 na zmianę postaw i potrzeb użytkowników, na
zmianę modeli biznesowych i systemów informacyjnych oraz
przedstawione zostaną główne kierunki rozwoju technologii
Web 3.0, wychodzących tym zmianom naprzeciw.
Charakterystyka Web 2.0
Web 2.0, zwana też siecią[...]
|
|
|
|
Twój Profil
Twój koszyk
