Low turn-off loss 4H-SiC insulated gate bipolar transistor with a trench heterojunction collector

In this work, an improved 4H-SiC insulated gate bipolar transistor (IGBT), or CTH-IGBT, with a trench p-polySi/p-SiC heterojunction on the backside of the device is proposed to reduce the turn-off energy loss (Eoff) and turn-off time (Toff). The electrical properties of the proposed and contrast structures are all simulated using the ATLAS simulation software to research the working mechanism of this improved structure. For the static performance, the specific ON-resistance (Ron,sp) and the figure of merit (FOM = VBR2/ Ron,sp) are not influenced much as compared to the traditional structure at the same breakdown voltage (VBR) of 12 kV. However, with a prominent electron current path formed by the heterojunction region of CTH-IGBT, a very available conduction path to discharge the electrons during turn-off process is proved in this article. The simulation results demonstrate that compared with the traditional structure, the turn-off energy loss of the CTH-IGBT is reduced by 76.4%, while the turn-off time is reduced by 85.0%.