In this work, an insulated gate bipolar transistor (IGBT) is proposed that introduces a portion of the p-polySi/p-SiC heterojunction on the collector side to reduce the tail current during device turn-offs. By adjusting the doping concentration on both sides of the heterojunction, the turn-off loss is further reduced without sacrificing other characteristics of the device. The electrical characteristics of the device were simulated through the Silvaco ATLAS 2D simulation tool and compared with the traditional structure to verify the design idea. The simulation results show that, compared with the traditional structure, the turn-off loss of the proposed structure was reduced by 58.4%, the breakdown voltage increased by 13.3%, and the forward characteristics sacrificed 8.3%.

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 = VBR 2 / 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 paper. 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%. Index Terms-4H-SiC, heterojunction, Insulated Gate Bipolar Transistor (IGBT), turn-off loss, turn-off time, breakdown voltage. I. INTRODUCTION he performance of silicon-based devices is gradually approaching its limits, and it has become increasingly difficult to meet the application requirements of modern power electronic systems. The third-generation semiconductor material silicon carbide (SiC) has gradually replaced the use of silicon (Si) in power applications due to its wide band gap, high breakdown electric field, high thermal conductivity, high electron saturation drift speed and higher radiation resistance. It is widely used to make high-power devices for application in high temperature, high voltage, high frequency and radiation resistant operating environments and requirements [1-6].