Snapback‐free reverse conducting IGBT with p‐float and n‐ring surrounding trench‐collector

Abstract

A reverse conducting (RC) insulated gate bipolar transistor (IGBT) with p-float and n-ring surrounding trench-collector is proposed. The p-floats surrounding sidewalls of trench-collectors suppress snapback and also avoid snapback when there are semiconductor/trench-collector interface charges (Q f). The n-rings surrounding the top of the trench-collectors speed up the forward recovery and ensure a high breakdown voltage. Technology computer aided design (TCAD) simulations are carried out to compare the proposed RC-IGBT and the RC-IGBT with p-poly trench-collector (PTC RC-IGBT). With Q f = 1 × 1011 cm−2, the proposed RC-IGBT is snapback-free while the PTC RC-IGBT has a snapback voltage of 4.43 V. The peak forward recovery voltage of the proposed RC-IGBT (12 V) is much lower than that of the PTC RC-IGBT (246 V). Besides, the reverse recovery charge of the two RC-IGBTs is 48% lower than that of the PiN diode.