Electrical characterization of 4H silicon carbide Schottky diodes under electron radiation

Abstract

Electronic components utilized in space missions are required to be radiation hard to maintain optimized electrical performance. Because of its wide bandgap, 4H-SiC based devices have been demonstrated to be the most suitable candidate for this purpose. This research investigates the effects of electron radiation on the electrical characteristics of 4H-SiC Schottky diodes. This thesis comprises of two parts: simulation and experimental part. The first part presents the simulation of current-voltage (I-V) characteristics of the Au/4H-SiC Schottky diode before and after irradiation. Simulation was performed using Silvaco Atlas TCAD simulation tool, where radiation induced traps was added into the structure of the simulated diode. The simulation results showed decrement in the forward (FB) and reverse bias (RB) leakage current after irradiation. This is believed to be caused by dopant deactivation due to the radiation induced traps. In the second part of the study, commercial 4H-SiC Schottky diodes were irradiated using EPS-3000 electron beam machine. After high dose of electron irradiation, FB current decreased while, RB leakage current increased. It is believed that, the increment in the RB leakage current is caused by generation-recombination (G-R) centers associated with electron-induce displacement damage. In addition, high temperature effects on the I-V characteristics of the diodes was also investigated. Temperature-dependent I-V simulations and measurements performed in the temperature range of 298 K–448 K. It was observed that FB and RB leakage current, series resistance Rs, barrier height Фb and saturation current Is are strongly dependent on the temperature.