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Shiv Nadar University

Silicon, apart from conventional integrated circuits, is also the basis for fabricating miniaturized 3-dimensional (3-D) mechanical structures. This paper presents a technique for the optimization of time duration of heat pulse required for transient thermography in silicon wafers. In the present work, a silicon diaphragm fabricated on one surface of a silicon wafer has been electro-thermally modeled as a 3-D Resistance Capacitance (RC) network. The region below the diaphragm was treated as a defect. Heat transfer by all three modes: conduction, convection and radiation has been taken into account. A C++ program generates the equivalent electrical circuit of the given sample, which was then directly simulated by SPICE (Simulation Program with Integrated Circuit Emphasis), a popular electrical circuit simulator. Experimental verification was performed on the silicon diaphragm sample. Prediction of a time duration in which temperature contrast of the sample reaches its maximum (saturation) value with minimum rise of sample temperature, is experimentally verified. This could be very useful in thermography situations where temperature rise should be no more than necessary to avoid potentially dangerous thermal stresses. Another possible use of the technique is for finding the heat flux of very short-pulsed heat sources.

World University root node

Electrical Engineering

Proceedings of SPIE - The International Society for Optical Engineering

Heat pulse optimization by SPICE simulation for transient thermography in silicon

The speed of operation of a reverse biased pn junction is evaluated using a streak camera. As such, power requirement for optical interconnects is calculated using the experimental value of quantum efficiency. It is shown from the results of the experiments that Si-based diodes are capable of operating in minimum of 10's of GHz and that is requires power less than conventional global metal interconnects on an IC.

High speed CMOS - Si light emitters for on-chip optical interconnect

Chemical Engineering

Chemical Engineering Education

Letter to the editor [3]

This paper presents computationally efficient artificial neural network technique for assessing the security of the power system against line outages. Performance index (PI), which accounts for various line limit violations per contingency, is defined. The basic purpose of ANN is to assess the severity of line outages in terms of PI, based on training examples from off-line analysis. The selection of input signals for ANN is influenced by the operating state of the system and the contingency in question which determines the extent of line power limit violations. In an attempt to attain perfection in PI prediction, suitable architecture and topology for the network is investigated. To expedite learning process, saturating linear coupled neuron model (sl-CONE) is also tried out. The effectiveness of proposed technique is demonstrated on 5-bus (7-line) and IEEE 14-bus (21-line) test systems. Computation efficiency of the method makes it potential candidate for inclusion in on-line comprehensive security analysis package. © 2002 Elsevier Science Ltd. All rights reserved.

International Journal of Electrical Power and Energy Systems

ANN for transmission system static security assessment

This paper presents modeling of transient thermography in terms of equivalent electrical parameters, its simulation using a popular circuit simulator SPICE (Simulation Program with Integrated Circuit Emphasis), followed by experimental verification. A novel current source based electro-thermal modeling of radiative heat sources is introduced. Analytic comparison of thermal and electrical circuits forms the basis for modeling and simulation of transient thermography experiments, in which the current source (modeling rate of incident radiative energy) drives a 3- dimensional (3-D) Resistance-Capacitance (RC) network (modeling heat conduction in the material). The current source value was derived from pyranometer-based measurements of the heat flux from the source. A mild-steel sample with a blind hole below the front surface, irradiated by a heat pulse, has been modeled by the proposed technique. SPICE then simulates the absolute thermal contrast of the surface as a function of time, in moderate computing time (seconds). The simulations compare well with experimental observations and similar to generally reported results. Current source approach, allows estimation of radiative heat flux necessary, to view sub-surface defects in a given material, at different depths, in general, and to predict time and magnitude of surface temperature over the defect and non-defect region in particular.

Current source modeling of radiative heat source in transient thermography simulation by SPICE

A non-contact, non-destructive technique for sensing the temperature of metal lines carrying alternating current is presented. The technique uses heterodyne laser probing, followed by measurements using lock-in amplifier. Predictions based on a developed theoretical model are in good agreement with experimental results.

Interconnect characterization: Joule displacement based laser profiling of periodic current carrying microconductors

We consider the following one- and two-dimensional bucketing problems: Given a set 5 of n points in R1 or R2 and a positive integer b, distribute the points of S into b equal-size buckets so that the maximum number of points in a bucket is minimized. Suppose at most (n/b) + Δ points lie in each bucket in an optimal solution. We present algorithms whose time complexities depend on b and Δ No prior knowledge of Δ is necessary for our algorithms. For the one-dimensional problem, we give a deterministic algorithm that achieves a running time of O(b4(Δ2 + logn) + n). For the two-dimensional problem, we present a Monte Carlo algorithm that runs in subquadratic time for small values of b and Δ. The previous algorithms, by Asano and Tokuyama [1], searched the entire parameterized space and required Ω (n2) time in the worst case even for constant values of b and Δ. We also present a subquadratic algorithm for the special case of the two-dimensional problem when b = 2.

Fulltext

Algorithmica (New York)

Improved algorithms for uniform partitions of points

Barriers to the industrial implementation of optical interconnects on an IC, center around the fabrication of optical elements on wafers through conventional Si processes. This paper focuses on demonstrating an all Si-based optical interconnect system that can be easily integrated into a conventional Si process. Most other approaches for optical interconnects use emitters that require drastic changes in conventional fabrication process. In this work, we demonstrate the ability to transmit electrical signals using Si-based system i.e. the light was generated by biasing the Si LED at avalanche breakdown voltage, light was coupled through a fiber cable made of SiO2 and inserted into a Si based avalanche photo-diode. Results presented demonstrate the switching behavior of Si LED in the GHz range, transmission of signal across the fiber, and measurement of signal limited by the BW of the receiver amplifier. © 2000 IEEE.

Proceedings of the IEEE 2001 International Interconnect Technology Conference, IITC 2001

All Si-based optical interconnect for signal transmission

The paper reports the study of vibrations occurring in a thin silicon membrane of a conventional capacity pressure sensor. The 20 μ-thick silicon membrane has an area of 6×6 mm. Vibrations induced on the membrane with the help of electrical excitation were studied using a heterodyne laser probe. The probe output gives a measure of the amplitude of vibration of the membrane. Using this technique spatial response of the capacitive pressure sensor diaphragm has been carried out. The resonant frequency peaks of the membrane were measured and the effect of air pressure loading observed.

Journal of the Indian Institute of Science

Laser probing of micromachined capacitive pressure sensor silicon membrane

Silicon p-n junction biased in avalanche breakdown emit visible light and its integration offer the potential for VLSI-compatible optical interconnect systems enabling next generation technologies and/or contact-less functional testing. The Si light emitters were stressed with AC, DC excitation and increased temperature to accelerate the aging. The results clearly show that the effects of AC, temperature stressing are negligible on light emission. DC stressing results in light coalescence for low values of current (less than 25mA) with total light emission coming out of the junction remaining constant. However, for DC stressing with large current (larger than 40mA) there is no significant variation of light emission. Changes in the light emission behavior for large and small values of DC excitations are consistent with a hydrogen migration model. The study revealed a strong dependence of light emission on the layout of test devices.