Improving dynamic characteristics for IGBTs by using interleaved trench gate

Abstract

In this paper, a novel trench insulated gate bipolar transistor (IGBT) with improved dynamic characteristics is proposed and investigated. The poly gate and poly emitter of the proposed IGBT are placed alternately along the trench. A self-biased p-MOSFET is formed at the emitter side. Due to this unique 3-D trench architecture, both the turn-off and turn-on characteristics can be greatly improved. During turn-off transients, the maximum electric field and impact ionization rate of the proposed IGBT are reduced and the dynamic avalanche (DA) is suppressed. The turn-off loss (E off) of the proposed IGBT is also decreased by 31% for the same ON-state voltage, when compared with the carrier-stored trench gate bipolar transistor (CSTBT). During turn-on transients, the built-in p-MOSFET decreases the reverse displacement current (I G_dis), contributing to low dI C/dt. As a result, the proposed IGBT achieves a 35% decrease in collector surge current (I surge) and 52% decrease in dI C/dt, when compared with the CSTBT with the same turn-on loss (E on), at I C = 20 A/cm2.