Mitigating self-turn-on failures in scaled carrier stored trench IGBT: a focus on poly-Si resistivity

Abstract Scaled insulated gate bipolar transistors (IGBTs) show improvement in electrical performance, but their lower gate threshold voltage ( V ge (th)) causes self-turn-on issues during high dV ce / dt or di c / dt switching conditions. In this study, we examine a carrier stored trench bipolar transistor (CSTBT) with a split-gate design to address the self-turn-on issue in scaled IGBTs. The split-gate configuration, which reduces Miller capacitance, helps to overcome self-turn-on failures of scaled split-gate CSTBT; however, the issue remains when considering the resistivity of poly-Si in the split-gates into account. To address this, we propose a selective-split-gate CSTBT design that resolves self-turn-on problems, even when poly-Si resistivity is considered. TCAD (Technology Computer Aided Design) simulations show that the proposed design is very effective in preventing self-turn-on and improves V ce (sat) by 24% compared to the scaled split-gate CSTBT.