500 V dual gate deep‐oxide trench SOI‐LIGBT with improved short‐circuit immunity

Abstract

A 500 V deep-oxide trench silicon-on-insulator (SOI) lateral insulated gate bipolar transistor (LIGBT) with improved short-circuit capability is proposed. The structure features dual trench gates: one gate (G1) extended to the buried oxide and the other gate (G2) arranged in the deep-oxide trench in the drift region. In the off-state, G2 acts as an emitter-side field plate to shield the lateral electric field from the collector side. In the on-state, negative voltage is applied to G2, leading to a hole inversion layer close to the deep-oxide trench. The hole inversion layer reroutes the hole current and provides an additional heat dissipation path. Experimental results show that the proposed structure exhibits high short-circuit immunity without degradation of the breakdown voltage. The short-circuit withstand time of the proposed structure is 1.55 times that of the conventional one, when the voltage of G2 is −5 V.