Sneha Kabra

Threshold voltage model for small geometry AlGaN/GaN HEMTs based on analytical solution of 3-D Poisson's equation

A simple and accurate analytical model for the threshold voltage of AlGaN/GaN high electron mobility transistor (HEMT) is developed by solving three-dimensional (3-D) Poisson equation to investigate the short channel effects (SCEs) and the narrow width effects present simultaneously in a small geometry device. It has been demonstrated that the proposed model correctly predicts the potential and electric field distribution along the channel. In the proposed model, the effect of important parameters such as the thickness of the barrier layer and its doping on the threshold voltage has also been included. The model is, further, extended to find an expression for the threshold voltage in the sub-micrometer regime. The accuracy of the proposed analytical model is verified by comparing the model results with 3-D device simulations for different gate lengths and widths.

Two-dimensional subthreshold analysis of sub-micron GaN MESFET

An analytical two-dimensional (2D) model to accurately predict the channel potential and electric field distribution in sub-micron GaN MESFET operating in the sub-threshold regime based on (2D) analytical solution of Poissons equation using superposition principle is presented. The results so obtained for channel potential, electric field, threshold voltage, etc are compared with simulated data using ATLAS 2D device simulator. The model is then extended to predict the current voltage characteristics and the effects of drain induced barrier lowering (DIBL) on the performance. Furthermore, the sub-threshold output characteristics of the device are also interpreted qualitatively.

A semi empirical approach for submicron GaN MESFET using an accurate velocity field relationship for high power applications

Abstract A semi empirical model has been proposed for sub-micron GaN MESFETs to calculate the I–V characteristics using an accurate velocity-field relationship obtained by fitting it with the Monte Carlo (MC) simulation. The results so obtained are compared with the experimental results to validate our model and are also compared with the results obtained from the simple saturation model to present the influence of electron drift velocity modeling on the device parameters. The model has been extended to predict the microwave parameters such as transconductance and output conductance of the device.

Asymmetric Gate Stack Surrounding gate Transistor (ASYMGAS SGT): 2-D Analytical Threshold Voltage Model

In the present work, a two-dimensional analytical model for novel device architecture, asymmetric gate stack surrounding gate transistor (ASYMGAS SGT) is presented and its effectiveness in suppressing short channel effects and hot carrier effects is investigated. The model is developed by solving the Poisson equation in cylindrical coordinates assuming a parabolic potential profile in the radial direction. Using the model, the expressions for potential and electric field have been obtained and the analysis is extended to obtain the threshold voltage of the device. It is demonstrated that besides improving the short channel immunity and hot carrier reliability, incorporation of asymmetric gate stack architecture also leads to enhanced transport efficiency. In order to verify the model, the analytical results have been compared with the simulated data obtained from device simulator ATLAS and a good agreement is found.

Impact of laterally asymmetric channel and gate stack design on device performance of surrounding gate MOSFETs : A modeling and simulation study

A two-dimensional analytical model is presented to study the impact of LACGAS device on the device characteristics. It is demonstrated that LACGAS leads to suppression of short channel effects such as threshold voltage (Vth) roll-off, drain induced barrier lowering (DIBL) and hot carrier effects. It also improves the transport efficiency owing to a greater gate control which is achieved by incorporating the stack architecture. Furthermore, LACGAS design also enables to obtain a high current drivability and enhancement in transconductance.

3-dimensional analytical modeling and simulation of fully depleted AlGaN/GaN modulation doped field effect transistor

We propose a simple and accurate three- dimensional (3-D) analytical model for the threshold voltage of AlGaN/GaN modulation doped field effect transistor (MODFET) taking into account the short channel effects (SCEs) and the narrow width effects (NWEs) present simultaneously in a small geometry device. The model includes the effect of vital parameters such as doping and thickness of the barrier layer on the threshold voltage. The accuracy of the proposed analytical model is verified by comparing the model results with 3-D device simulations. It has been demonstrated that the proposed model correctly predicts the potential, the electric field distribution along the channel and the threshold voltage.

Development, use and impact of e-learning based modules for teaching electronics: To undergraduate girl students: A case study

This paper presents the development, use and impact of e-learning resources on undergraduate girl students. The paper compares the conventional method of teaching vs the use of ICT tools for teaching. An interesting component of our study is that the ICT tools have been developed by students themselves under the guidance of a teacher.

Development of e-learning based module for teaching practicals in electronics to science and engineering students in India

The paper contains the description of entire process of development of e-learning module including animations, videos and power point presentations of various devices used in electronics practical laboratories by science and engineering students in India. In this work, we have focused on using multimedia technology as an innovative teaching and learning strategy in a problem-based learning environment. The work presented in this paper shows the use of e-learning based approach to make learning of electronics practical more effective and interesting.

Asymmetric Multilayered Gate Dielectric (AMGAD) surrounding gate MOSFET: A new structural concept for enhanced device performance

A two-dimensional analytical model for asymmetric multilayered gate dielectric surrounding gate MOSFET (AMGAD SGT) is presented and its effectiveness in suppressing short channel effects and hot carrier effects is examined. The expressions for potential and electric field have been obtained and the analysis is extended to obtain the threshold voltage and subthreshold slope of the device. It has been established that incorporation of asymmetric multilayered gate dielectric design leads to enhanced carrier transport efficiency besides also improving the short channel immunity and hot carrier reliability. The model is verified by comparing the analytical results with the simulated data obtained from device simulator ATLAS and a good agreement is found.

An analytical model for admittance parameters of GaN MESFET for microwave circuit applications

An analytical model of GaN MESFET to evaluate admittance parameters is presented. Frequency dependence of the parasitic capacitances obtained by simulations has been utilized to develop the model. Results have been verified using ATLAS 2D device simulator.