Robustness Analysis of 1200-V IGBT Under Extremely High-Gate Voltage Stress

Abstract

In this study, the robustness of insulated gate bipolar transistors (IGBTs) under extreme high-gate voltage stress (both positive and negative) is comprehensively investigated. The results indicate that all IGBTs maintain essential electrical characteristics, demonstrating considerable robustness to extreme gate voltage stress. However, varying degrees of degradation are observed depending on the polarity of the applied stress. Specifically, under high-positive gate voltage stress, the threshold voltage remains nearly stable, whereas under high-negative gate voltage stress, a significant increase in the threshold voltage is noted. Based on these findings, the degradation mechanism is proposed and experimentally validated. For negative gate voltage stress, degradation primarily results from electron injection from the gate, with elevated temperatures accelerating this process. In contrast, under positive gate voltage stress, the hole injection efficiency is much lower than that of electrons, and part of the gate voltage is absorbed by the depletion region. Additionally, G–V measurement, C–V measurement, and simulation are conducted to support the proposed mechanism. This work contributes to a deeper understanding of IGBT degradation mechanisms under high-gate voltage stress, offering insights relevant for their application in high-stress operational environments.