Electro thermal transient simulation of silicon carbide power MOSFET

This research focuses on the transient performance of N-Channel Silicon Carbide (4H-SiC) vertical D-MOSFET structure at 300K and elevated temperature conditions. Transient analysis enables the designer to understand the thermal stress the semiconductor device undergoes while dissipating high power for short period of time. Silicon carbide has been a material of interest in the development of high power semiconductor device especially due to its wide band gap and high temperature operational stability [1]. The 2D device model was created and simulated using Silvaco^© ATLAS Technology Computer-Aided Design (TCAD) physics based simulation software [2]. The MOSFET was designed for a blocking voltage of 1200V and a rated drain current of 1A at 100A cm^-2 current density. Physics based models were included to accurately model electrical device parameters like mobility, impact ionization, lattice heating etc. In order to first verify the proper functioning of the MOSFET cell, the device structure was simulated for its DC characteristics which includes Breakdown characteristics, Drain current and Drain voltage characteristics, Transfer characteristics and Body diode forward conduction characteristics. For the transient analysis, the device was simulated for transient conditions pertaining to current densities of 500A cm^-2 and 1000A cm^-2 and pulse width varying from 50μs to 1ms. Silvaco^© ATLAS introduces a scaling factor for 2D simulations where the node variables like current gets scaled as per the value mentioned for the third dimension The scaling factor was optimized to obtain the required current density. Each simulation was performed using a current pulse generated through an RLC ring down circuit.