TCAD simulation on an UACCUFET inserted with 3C/4H–SiC hetero-crystalline junctions for accumulation-channel and fly-back

Abstract

Due to high channel mobility, SiC accumulation-channel field-effect transistors (ACCUFETs) exhibit important research and application values in high-frequency and large-power fields, but still encounter poor reverse recovery, etc. An enhancement-mode U-shaped gate ACCUFET integrated with 3C/4H–SiC hetero-crystalline junctions (HCJs) and semi-super-junction (SSJ) is constructed, where a (n⁻)4H–SiC-layer in (n)3C–SiC/(n⁻)4H–SiC HCJ is adopted to form accumulation-channel for conduction due to field-effect, another HCJ composed of (n)3C–SiC and (n)4H–SiC drift region is employed for fly-back under low cut-in voltage (V_F) to shorten reverse recovery time (t_rr). Additionally, a SSJ is used to raise the breakdown voltage (V_B). The device structure and performance are optimized by the Silvaco TCAD, which illustrates the values of V_B and static figure of merit (FOM_HM) are increased by 15.6 % and 5.6 % respectively compared to those of the counterpart with Schottky barrier diode. This paper can provide new ideas for devising high-performance ACCUFETs.