Modeling of gallium nitride transistors for high power and high temperature applications

Abstract

Wide bandgap (WBG) semiconductors such as GaN and SiC are emerging as promising alternatives to Si for new generation of high efficiency power devices. GaN has attracted a lot of attention recently because of its superior material properties leading to potential realization of power transistors for high power, high frequency, and high temperature applications. In order to utilize the full potential of GaN-based power transistors, proper device modeling is essential to verify its operation and improve the design efficiency. In this view, this research work presents modeling and characterization of GaN transistors for high power and high temperature applications. The objective of this research work includes three key areas of GaN device modeling such as physics-based analytical modeling, device simulation with numerical simulator and electrothermal SPICE model for circuit simulation. The analytical model presented in this dissertation enables understanding of the fundamental physics of this newly emerged GaN device technology to improve the operation of existing device structures and to optimize the device configuration in the future. The numerical device simulation allows to verify the analytical model and study the impact of different device parameters. An empirical SPICE model for standard circuit simulator has been developed and presented in the dissertation which allows simulation of power electronic circuits employing GaN power devices. The empirical model provides a good approximation of the device behavior and creates a link between the physics-based analytical model and the actual device testing data. Furthermore, it includes an electrothermal model which can predict the device behavior at elevated temperatures as required for high temperature applications.