A Novel IGBT with Variable Conductance Path Realizing Both Low $V_{on}$ and Turn-off Loss

Abstract

A novel low loss Insulated Gate Bipolar Transistor (IGBT) with variable conductance path (VCP) is proposed in this paper. The conductance of P-doped VCP is controlled by the depletion region generated around the depletion gate (DG). In the blocking state, VCP has high conductance and shorts P-well to the emitter. In the on-state, VCP has low conductance and the current can hardly flow through. Accordingly, the highly doped carrier stored (CS) layer would not affect the breakdown voltage (BV) of VCP-IGBT while it can effectively form the hole barrier to obtain low on-state voltage ($V_{on}$). In addition, when VCP-IGBT is turning off, the depletion region near DG vanished. VCP changes to the high-conductance state and extracts carriers directly out of the device, contributing to a low turn-off loss ($E_{off}$). Simulation results show that, under the same $E_{off}$, VCP-IGBT reduces $V_{on}$ by 20% compared to CSTBT and 17% compared to SBL-IGBT without decreasing static and dynamic blocking capability.