A Low Loss and On-State Voltage Superjunction IGBT with Depletion Trench

In this paper, a novel superjunction IGBT with a depletion trench (DT SJ IGBT) is proposed and investigated by simulation. In the on-state, the depletion trench together with gate trench depletes the P-pillar between them and thus forms a hole barrier to realize an enhanced carrier store effect. Unlike the conventional (Con.) SJ IGBT, the DT SJ IGBT maintains bipolar conducting mode in the on-state even with high N/P pillar doping of $8 \times 10^{15}\mathrm{cm}^{-3}$. In the blocking state, P-pillar is shorted to P+ emitter and then protects the corner of trench gate from being prematurely breakdown. During the turning off, the depletion region between the two trenches gradually disappears and forms a hole extraction path to decrease $E_{off}$. Compared with Con. SJ IGBT, the $V_{on}$ is reduced by 38.8% at the same $E _{off}$ and almost irrelevant to pillar doping. Compared with SJ-IGBT with floating P-pillar (FP SJ IGBT), the DT SJ IGBT increases the BV by 19.7% and decreases the $E _{off}$ by 23.4% at the same $V_{on}$.