Simulation of electrons irradiation damages to optimize the performance of IGBT

Abstract

Electron irradiation (IE) is a technique used to control IGBT switching performances and then produce series of IGBTs with various switching velocities. However, this irradiation introduces undesirable effects on other parameters, such as the forward voltage drop and leakage current. In this paper, we propose a method to optimize the performance of the IGBTs considering the degradation effects. The IE effects are simulated using the two-dimensional device simulator ATLAS. Defect densities defined by their energy levels and capture cross section, and densities are introduced into all the structure layers. The energy levels and capture cross sections are extracted from literature and densities are obtained by an iterative process, where the simulated characteristics are fitted to the experimental ones. This method validity is confirmed by comparison of simulation results with experimental ones performed onto a series of IGBTs irradiated to various doses. Steady states and switching characteristics obtained by both simulation and measurements are in good agreement and variations of forward voltage drop versus turnoff time for various doses are obtained and used for performance optimization purposes.