Simulation Study of Novel Trench Gate U-Shaped Channel SOI Lateral IGBTs With Suppressed Gate Voltage Overshoot and Reduced di/dt

Jie Ma,Feiming Huang,Weifeng Sun,Jing Zhu,Long Zhang,Wangming Cui,Sen Zhang,Nailong He,Yan Gu

doi:10.1109/ted.2021.3084578

Abstract

The gate voltage overshoot during the turn-on transient in the trench gate U-shaped (TGU) channel silicon-on-insulator lateral insulated gate bipolar transistor (SOI-LIGBT) is investigated and novel structures are proposed for the first time with numerical simulation in this article. The TGU SOI-LIGBT features two U-shaped trench gates, G 1 and G 2 , connected together. The U-shaped trench for G 2 serves as a hole barrier trench. A large number of holes accumulate in the U-shaped region during the turn-on transient because of the U-shaped architecture and the hole-blocking effect of G 2 . The displacement current induced by the nonuniform distributed holes overcharges the gate and leads to high di/dt. In this article, the novel structures (Novel-1 and Novel-2) with G 2 partially filled by the polysilicon are proposed for the improvement in gate voltage overshoot while keeping superior turn-on loss ( E ON ). The novel structures (Novel-1 and Novel-2) can suppress the hole accumulation and slow down the rising of the electric potential in the silicon region near the G 2 . The di/dt can be lowered and the displacement current that overcharges G 2 can be effectively shielded. Compared with the conventional TGU structure, the di/dt of the Novel-2 are improved by 56.3% at the same E ON of 2.4 mJ/cm 2 .

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