An 800V ultra-low loss field-stop insulated gate bipolar transistor with extended polysilicon gate structure

Abstract

This paper proposed a Insulated Gate Bipolar Transistor with extended polysilicon gate structure (EPG IGBT) based on P-type drift region (P-Drift), which has electron inverse and accumulation layer. It designs the gate as an extended gate structure with a Bipolar Junction Transistor (BJT), extending into the collector region, and the BJT is always blocked during the switching process. When the EPG IGBT is conducting, the Nj region has a constant positive voltage, which causes the P-Drift to form an electron inversion layer and conduct. Through TCAD simulation, the EPG IGBT maintained the same Breakdown Voltage and turn-off time, while reducing its forward voltage drop (VCE(sat) = 0.98 V) and turn-off loss (Eoff = 0.89 mJ/cm2) by 36 % and 44 %, respectively, compared with FSSJ IGBT of the same process (VCE(sat) = 1.53 V, Eoff = 1.58 mJ/cm2). In addition, the static latch-up I–V and Forward Biased Safe Operating Area (FBSOA) of the EPG IGBT have been significantly improved, providing a new approach for optimizing IGBT.