2D-TCAD Simulation Study of Capture Layer and Repellent Layer of Current Filament in Trench-Gate IGBTs

For reliability designs of high voltage power devices, it is very important to understand and control local heat generation caused by current filaments. The current filament is a phenomenon that currents are concentrated in some cells and is caused by the instability inherent in the devices. It moves around in the active region of the device and locally raises the Si lattice temperature of the passage mainly due to Joule heat. It slows down at terminal boundaries or defective cells and is likely to create a hotspot and damage the device. Therefore, keeping the current filament away from such weak places and confining it in a structure specialized for heat dissipation effects are useful for the reliability design of the device. By changing a part of the field stop layer of the IGBT to a capture layer or a repellent layer to control the movement of the current filament, the current filament can be confined in the capture layer or kept away from the repellent layer. The purpose of this paper is to investigate the mechanism of current filament capture and repellent so that they can be used as one of the effective means of device reliability design.