Active trench barrier RC-IGBT with pinch-off and carrier accumulation effects

A Reverse Conduction Insulated Gate Bipolar Transistor (RC-IGBT) featuring an Active Trench Barrier (ATB) based on Super-Junction (SJ) technology is proposed and investigated. The double-trench gates are designed at the N-pillar and P-pillar of the SJ drift. Consequently, a p-type ATB located between the two trench gates is formed. The ATB working mechanism is controlled and modulated by the Gate Voltage (VGE) of the double-trench gates. In the forward conduction state, the ATB channel is depleted and automatically pinched off by the positive VGE. Thus, the barrier potential of the ATB is remarkably improved. Additionally, holes accumulate underneath the ATB and maintain high conductivity modulation of the SJ drift region. Thus, the low on-state voltage drop (VON) is obtained. In the reverse conduction state, the ATB pinch-off effect automatically fades away with the grounded VGE. In addition, the ATB, P-pillar, and N + act as the anode, drift, and cathode of the Free-Wheeling Diode (FWD), respectively. Electrons are blocked and accumulated by the trench gates. Thus, the hole injection is enhanced and the reverse conduction voltage (VR) is reduced. In the turn-off state, excessive holes can be effectively extracted by the extra ATB channel, and the turn-off loss (EOFF) is remarkably decreased. As a result, the trade-off relationship between VON and EOFF can be significantly improved, which achieves the best comprehensive property when compared with the conventional RC-IGBT and SJ-IGBT.