The department has a long experience in Microprocessor/ PC based system
design . Several application systems including Hardware and Software were
developed as a part of the department`s research activities. Of late
embedded systems with built in microcontrollers are being developed.
Identifying specific applications, developing MIMICs of real systems,
interfacing and software designs are the major activities carried out under
this laboratory. Software for Metrology and Automatic trajectory tracking
has been developed. Odor sensing based on Pattern recognition and Artificial
Neural Networks is being investigated. The faculty of the department is also
involved in Modeling and Simulation activities. Computer simulations are
related to nonequilibrium phenomena, semiconductor devices and processes.
The department has a longstanding program of VLSI design. The department has
participated in a National Program of Technology Simulator Development
sponsored by DOE. The laboratory focuses on applications of Digital Signal
Processing and Image Processing in various fields. The DSP applications have
been developed for speech recognition and synthesis. PC based Image
Inspection systems using Reference comparison as well as Feature extraction
approaches have also been realized. Software for metrology and Automatic
trajectory tracking has been developed. Work on Tactile data processing and
analysis is underway. Odor sensing based on Pattern recognition and
Artificial Neural Networks is being investigated. This laboratory is another
major part of the infrastructure wherein the student`s dexterity with
regards to the microprocessors and computers is improved.
A PC based odor sensing system (PCBOSS) has been
designed. A software package ODAP has been developed for acquisition and
analysis of odors. The system has been successfully used for the
identification of various gases, analyzing mixtures, detection of odors like
perfumes, essences, ethers and alcohols. An analog circuit to implement the
electronic nose has also been developed.
Development of a laboratory in which students could
carry out experiments over the web has been taken up as a UGC project.
Presently basic experiments related to device characterization and digital
electronics are being set up. With the advent of Internet and World Wide Web
with horde of information the teaching methods need to be upgraded. The
class room teaching needs to be supported with hands on laboratory exercises
even in the commercial training systems. Many of the learning courses
launched to date provide a good alternative/ complaint to classroom teaching
with the support of web enabled multimedia lessons. However especially for
courses like electronics just the multimedia presentation is not enough and
feels of actually working on a real system observing the positive and
negative results of various actions is must. In view of such a need for
hands on, many a times online courses need to be added with a laboratory
In the past, students had to be in the laboratory to gain practical
experience; with effective remote laboratories, students can be anywhere.
Practical experience is a very important part of engineering education, but
it is resource intensive. Designing and conducting experiments can take
time, money and energy. Sharing experiments locally and remotely allows
unique laboratory experiment to be utilized more fully, brings down the
experiment cost per student, and more time available to students. Our goal
with the remote laboratory paradigm is to make the equipment that we already
have available to more students without taking away the experience of being
physically present in the laboratory. Internet provides the communication
infrastructure between students and the experiments.
The objectives of the project could be briefly stated
Explore the range of WWW technology available for preparing the course
Experiment with the use of features offered by Netscape, CGI scripts and
Java in imparting knowledge.
Prepare course material for the courses.
Use the material for various student groups and update it based on student's
The achievements during the course of past one year could be stated as
Review of work on online courses and remote experimentation using web
Study of Java, Java applets, Graphics and CGI scripts.
Implementations of Electronic Components like transistors, diodes,
resistors, gates etc for CyberLab.
Trajectory Plotting System (ATPS):
A system for digitizing and analyzing a sequence of
images and obtain the trajectory of a particular object has been developed.
The software is menu driven and user interactive. The ATPS could be used for
a number of applications. It has been used for tracking a moving vehicle and
FPGA based system design:
Work on implementation of Algorithms and systems in Field programmable gate
arrays is being carried out. A digital frequency meter, printer interface,
template search routine and image registration has been realized.
Tactile Sensing System:
A PC Based tactile sensing system has been designed. A menu driven software
package providing various options for acquisition and analysis of data has
been designed. The system has been used for identification of geometric
MATERIALS and MEMS LABORATORIES:
The department possesses good research level
facilities for fabrication of discrete semiconductor devices. Oxidation and
Diffusion furnaces, vacuum evaporation and magnetron sputtering systems for
metallization, ebeam evaporation system, photolithography setup, ebeam
lithography system are the important facilities available in the department
in fabrication laboratory ( FAB Lab ). The FAB Lab has a fully equipped
yellow room for optical lithography purpose. A SEM and plasma processing set
up are also available for material characterization/processing . Development
of Silicon based and thin/thick film microsensors is another activity
carried out in the laboratory. A system has been made by setting up for
micromachining of silicon and it has shown encouraging results in the
attempt to fabricate micropressure sensors. This laboratory is engaged in
carrying out research on synthesis and characterization of Plasma
Polymerized Electron Beam Resist.
Triple purpose EBL system using SEM model S120:
Lithography is a technique of transferring of pattern from mask to workpiece.
Electron beam lithography (EBL) uses electronic beam as a source of exposure
and is mainly used for the mask fabrication for optical and Xray
lithography. Commercially available EBL machines are very expensive and are
unaffordable to many.
A successful attempt has been made to develop an in-house EBL system (lc
EBLS1), around a Scanning Electron Microscope, Type SEM120, Cambridge
instruments. This is a triple purpose system. It can be used to evaluate the
resist, to make mask and to inspect the mask or pattern delineated in the
resist. A user friendly software is developed to have a fine control over
the electron beam. The SEM is calibrated for the measurement of the electron
beam dose. Fabrication of transducers like SAW devices, optical gratings,
silicon based sensors, strain gauges etc. which requires fine control of
line patterns of extremely small dimensions are carried out using this
Polymers as Masking Material for silicon micromachining: i) PMMA, ii) PTFE,
Polymers can be very good alternative to SiO2 and Si3N4 which are normally
used masks for the anisotropic etching of silicon in etchants like KOH. PMMA
has been extensively studied due to its use in numerous applications.
Adherent PMMA layer can be conventionally used as a mask material as it is
cheaper, easily deposited and removed. PMMA can be deposited by different
techniques like plasma polymerization, thermal coating, DC and RF sputtering
In the present work the deposition of PMMA is carried out using DC
sputtering system at a pressure of 0.2 Torr in argon gas (carrier gas)
plasma. The DC plasma power was varied from 540W and the deposition time
from 2035min. The structural characteristics of the deposited films was
carried out by NMR, FTIR and contact angle measurement. FTIR and NMR shows
bond formation between silicon substrate and the deposited polymer film.
From the contact angle measurement, the interfacial tension value obtained
for sputtered PMMA layer is 0.8dyne/cm, which is in good agreement with the
reported one. This indicates that the sputtered PMMA layer adheres well with
the silicon substrate.
The masking properties of sputtered deposited PMMA was carried out by
immersing the deposited films in aq. KOH solution of 20wt% concentration at
6080oC. The masking time of 300min at 80oC KOH temperature is achieved with
the silicon etch rate of 86m/hr. These results show that, DC sputtering of
PMMA gives better adhesion of polymer to the substrate and enhance the
surface wetability and hence works well as a good masking material for
silicon micromachining. Further on the same lines work on the test of
masking properties of PTFE and HEMA is also done.
and Analysis of various MEMS structures using MEMCAD and ANSYS software:
Micro Electromechanical Mechanical Systems (MEMS) devices are generally
geometrically complicated and innately 3dimensional. Appropriate Computer
Aided Engineering (CAE) allow designer to model, simulate, modify and
optimize the MEM device structure, process and design. FiniteElementAnalysis
(FEA) is one of the numerical methods that is not restricted by size
considerations of a structure and is always suited for the study of
microminiature structure of MEMS devices. The modeling of inertial
piezoresistive sensor a MEM device is done by using one of the CAE tools
i.e. FEA tools, ANSYS. A sensor structure consisting of a pi shaped proof
mask and piezoresistive doped flexure is modeled in variety of sizes. FEA is
carried out for computing sensorsensitivity through measurement of strain in
the flexure by statistically loading the proof mask.
After the extensive simulations of various types of structures, a novel
technique has been evolved to maximize the performance of acceleration
sensor. This technique involves placement of lumped mass on a proof mass at
a particular position from anchored end, which results in optimized product
of stress and bandwidth. The design optimization for piezoresistive inertial
sensor in respect of maximization of sensitivity and bandwidth has been
Thin Film Studies
Deposition of Silicon nitride (Si3N4) and Indium nitride (InN) by ARE
Activated Reactive Evaporation (ARE) process is implemented for the
deposition of silicon nitride as well as indium nitride thin films at room
temperature. In the Activated Reactive Evaporation (ARE) process, evaporated
material by ebeam/ resistive heating enters in the nitrogen plasma zone,
excited by inductively/parallel plate RF power (13.56MHz) source and the
films get deposited on the substrate. Large number of experiments were
carried out for optimization of the process parameters.
The deposited films of silicon and indium nitride are characterized by
various characterization techniques like Elliposmetry for refractive index
measurement, Xray Diffraction (XRD), Xray Photoelectron Spectroscopy (XPS),
Fourier Transform Infrared (FTIR) spectroscopy, Energy Dispersive Analysis
of Xray (EDAX) for chemical and structural analysis and topography by
Scanning Electron Microscopy (SEM). The results obtained from these various
analysis show the feasibility of using ARE technique for the deposition of
silicon and indium nitride thin films.
Polymer based Humidity sensor
In order to fabricate humidity sensors using polymeric materials,
modification of the polymer material by chemical or some other means to meet
the requirements for reliable humidity sensor is necessary. In case of
capacitive type humidity sensor, hydrophobic polymers are used to fabricate
the sensor. It is found that the polymer should have a few microvoids as
possible so that the adsorbed water molecules are isolated in order not to
form clusters. The formation of clusters leads to appreciable hysteresis.
The aim of the present work is to synthesize a new polymer material,
basically PMMA, for humidity sensing in which sensitivity could be improved.
In this regard two methods are employed: In the first case the aim is to
synthesize PMMA via plasma polymerization route using MMA as the base
monomer in an inductively coupled plasma polymerization reactor and to study
the RH response of the PPMMA films deposited under various conditions. In
the second case the objective is to study the effect of argon and nitrogen
plasma treatments on PMMA and consequently for the first time its effect on
RH response of the polymer with respect to sensitivity, hysteresis and
response time. The "Inter Digited Capacitor (IDC)" pattern is transferred on
chromium coated glass substrate by photolithography. These samples were
exposed to the plasma polymerization of MMA at a reactor pressure of 102
Torr in argon as well as nitrogen (carrier gas) plasma. After the plasma
treatment the samples were exposed to different humidity and the sensor
responses were recorded.
Silicon based Hall
sensors for RPM measurement
Hall sensor is developed indigenously for use in Automobile industries for
RPM measurements of the wheels. Single crystal Silicon (ntype, (100)
orientation, and = 35 cm) is used as Hall sensor material. Ti - Pt - Au were
used as the electrode material for Hall Sensors. These metals were deposited
by E beam evaporation. The pattern was transferred by lift off technique.
The sensors were separated out and tested thoroughly. These sensors are
stable with respect to time as well as temperature (R.T to 55 ?C). They have
linear Hall characteristics and the contacts are ohmic.
This has been proved mathematically by considering work functions of each
and through the experiments as well. The Halldevices so fabricated are
tested for Hall voltage, using the setup built in house. Si based Hall
devices and RPM measurement system consisting of Signal Conditioning Unit (SCU),
Optical Isolator for separating analog and digital ground, Counter and Power
Supply is successfully fabricated. The same is handed over to VRDE,
Ahmednagar, for its application in RPM measurement. These circuits were
developed using discrete components initially. Now they are fabricated using
SMDs (surface mount devices) as well.
Synthesis of Dry Electron
Beam Resist by Plasma Polymerization
Work is done on synthesis and characterization of plasma polymerized
electron beam resists. An inductively coupled tubular reactor is employed
for plasma polymerization. Methyl Methacrylate (MMA), Styrene, aMethyl
Styrene are the monomers for resist synthesis. Copolymerization and doping
of resists by metals and gaseous species like Sulfur (S), Fluorine (F) is
being done for improving the sensitivity of the resist.
Plasma Polymerization is a dry and clean process, which gives pinhole free
resist whose characteristics can be tailored easily.
Plasma Polymerized MMA resist synthesized in the laboratory is found to be
self developable and has very high sensitivity compared to the conventional
ones. S and F doping further increases the sensitivity.
Development of NOAA receiver
Data on various earth survey related parameters are available from
geostationary (distance of about 36000km) and polar (e.g. NOAA at distance
of 830km) satellites. There are few data collection centers in India
especially in national laboratories only. A low cost receiver for National
Ocean for Atmospheric and Administration (NOAA) satellite for collecting the
atmospheric data has been designed and developed. A typical receiver
consists of receiving Antenna (AE), Low Noise Amplifier (LNA), Filter,
Mixer, IF amplifier and Down converter with PC for imaging. Power output
requirements from various stages are calculated and the stages are designed.
Parabolic reflector AE with helical feed to operate at 1.7GHz has been
designed and fabricated. Azimuth and elevation control for tracking the
satellite is done through PC. The components, active and passive, are
selected to give the expected performance and cost.
OPTOELECTRONIC SENSORS AND SYSTEMS LABORATORY
Optoelectronics includes study of Light sources,
transmission media and photodetectors. The research activities carried out
in the Optoelectronic Sensors and Systems Laboratory include development of
Integrated Optical components, MSM photodetectors, Universal Signal
Conditioning system and fiber optic sensors for mechanical and chemical
applications. Transmissive ESLMs using twisted pneumatic liquid crystal are
designed and fabricated consisting of a 32 x 32 matrix pixel for
optoelectronic logic processing. Presently, the activities are related to
optical waveguides fabricated in glass using the ionexchange technique.
Stress is laid on the sensing applications of integrated optic devices.
Embedded Optical Fiber Sensor
Developed and optimized fiber optic based micro displacement sensor. The
sensor is also used for strain, and load measurements. The strain and load
measurement range can be selected with different diaphragms. This is optical
reflectance measurement type sensor probe.
Multi wavelength fiber optic based fluorescence sensor for chemical analysis
like pH, concentration and RI measurements of liquid and fluids.
Fiber optic U shaped and Planer Optical Waveguide based online RI monitoring
and measurement sensor for liquids and fluids in Sugar Industries, Food
Processing and Chemical Industries to analyze the concentration of
ingredients, turbidity and viscosity etc.
TriColorimetry based fiber optic probe for color sensing
These sensors are accommodated with individual signal conditioning and
processing modules based on discrete components, microcontrollers and PCs.
Application areas include Process, Instrumentation manufacturers, Sugar,
Chemical, Food Processing, Paper and Textile Industries.
Rapid Thermal Processing
Developed in this laboratory is designed for semiconductor wafer processing
at temperature in excess and of the order of 1000OC with a ramp up rate of
220 OC in a matter of about 5 to 6seconds. The SS process chamber is
isolated form the heating lamps with quartz separators. A gas premixing
assembly with MFCS allows mixing of up to 4 corrosive/noncorrosive gases.
Thus making the system capable of working in variety of environments.
Provision is also made to attach rotary pumps for processing in vacuum. PC
based recipe controller software provides overall monitoring and control.
The dedicated PID controller maintains the wafer temperature within 5OC.
A Virtual Instrumentation lab has been set up in
collaboration with National Instruments, a Texas based company. Virtual
Instruments for various applications are being developed.
The field of instrumentation has been revolutionized with the advent of
computer age. Today the front panel as well as hardware of the instrument is
being substituted with software, making the instrument cheaper, more
versatile and virtual. The concept of virtual instrumentation has not only
influenced the industry but is also affecting traditional academic research
and teaching. It gives the ability to transform a personal computer into a
number of powerful Virtual Instruments. The field of VI is breaking down the
barriers developing and maintaining instruments that challenge the world of
test, measurement and industrial automation.
Today globally competitive economy requires scientists, engineers and
technicians who are competent with products used in the industry. The
Department of Electronic Science has acquired expertise in the field of
Microprocessor/PC based Instrument over the past 20 years. The research
activity is focused on Intelligent Instrumentation along with DSP, Image
processing, Machine Vision, Neural Network and Fuzzy Systems. Considering
the expertise available in the Department, National Instruments, a Texas
based company has come forward to collaborate and setup a Virtual
Instrumentation laboratory on the Pune University Campus.
Hundreds of universities, technical schools abroad have made transition to
virtual instrumentation. The emergence of computers as a multipurpose
engineering and scientific tool can make researchers, teachers more
productive and change the way students learn. The computers can be
transformed into powerful, multipurpose laboratory tools that can replace
expensive, outdated equipment.
The department has been actively pursuing the research in basic and applied
sciences along with various developmental projects. This part of the
research has been an integrated part with a view to understand and
contribute to the future technology to come. Following is a brief summery of
the research done. Dr. Shaligram has participated in the MOSTEC programme
initiated at all India level to develop a software package for MOS
processing. This was an attempt to analyze various processes as surface
chemical processes and connecting the outcome to the experimental
macroscopic parameters. The software was published in 1990.
Software is developed for IV characteristics for a MOS transistor. The
program involved calculations of 2D states of triangular potential well for
silicon at the oxide interface. The calculation of current involved the
Monte Carlo method to sample the electrons representing the current. Various
scattering processes were included within effective mass approximation
including ee scattering. This lead to very satisfactory results with
In association with Univ. South. Cal. USA a code for atomistic growth of
GaAs and AlGaAs using known diffusion coefficient and relevant properties of
corresponding elements in the vapor form has been developed. This work has
successfully explained various observations on IIIV compound growth
including RHEED oscillations, temperature dependence of layer by layer
growth, roughening of interfaces between GaAs and AlGaAs, etc. The work is
still cited in many publications.
In another collaboration with University of Maryland USA, simulations on
various models are carried out to understand the statistical physics of
growth. This included conservative as well as non conservative growths.
Collaborative work with U. Mich. Ann Arbor, USA is being carried out to
understand the catalytic behavior of CO on Pt surfaces. The main interest
was to understand the oscillatory behavior of surface reaction. This turns
out to be a problem in non linear dynamics. Using methods in NLD, we have
successfully obtained the simulation results on oscillatory reactions.
Further, we also studied the problem of brittle cracks in SiO2. The well
known fact that the micro cracks are developed well before the critical
stress is applied was explained using the effect of viscosity and thermal
noise. The simulation results with parameters for SiO2 match well with
corresponding experimental data.
Recently work is being carried out on establishing electronic structures of
quantum dots of CdSe and ZnSe along with other collaborators in Physics
Dept. of the Pune University. This study is intended to explain some of the
experimental observations in spectroscopy related to quantum dots and also
the diffusion behavior of nano particles.