An Ultralow Loss Superjunction Reverse Blocking Insulated-Gate Bipolar Transistor With Shorted-Collector Trench

Abstract

A novel superjunction (SJ) reverse-blocking (RB) insulated gate bipolar transistor (IGBT) is proposed and investigated for the first time. The device features a shorted collector trench (SCT) at the bottom, an SJ structure in the drift region, and an N1-layer as well as N2-layer at the bottom and top side of N-pillar, respectively. First, the SCT combined with the N2 enables the SJ RB-IGBT to sustain a high reverse breakdown voltage (BV $_{\textit {R}}$ ). The SCT assists in depleting the N1 in the reverse blocking state, enabling a high BV $_{\textit {R}}$ under the condition of a high N1 doping that is required to maintain a high forward breakdown voltage (BV $_{\textit {F}}$ ). The N2 acts as a field-stop layer in the reverse blocking state. Second, unlike the conventional SJ IGBT, the SJ RB-IGBT maintains bipolar conducting mode in the ON-state even with high N/P pillar doping of $6 \times 10^{15}$ cm $^{\mathrm {-3}}$ , due to carrier store effect induced by N2. Thus, a low ON-state voltage ( $\text{V}_{\mathrm{\scriptscriptstyle ON}}$ ) is obtained. Third, the SJ junction extracts the plasma into separate pillars during turn OFF, enabling a fast turn-OFF speed that is comparable with unipolar devices. The SJ RB-IGBT realizes bidirectional blocking capability >1200V and turn-OFF loss 80% lower than that of the state-of-the-art RB-IGBT.