12-kV p-Channel IGBTs With Low On-Resistance in 4H-SiC

Abstract

SiC bipolar devices are favored over SiC unipolar devices for applications requiring breakdown voltage in excess of 10 kV. We have designed and fabricated p-channel insulated-gate bipolar transistors (IGBTs) in 4H-SiC with 12-kV blocking voltage for high-power applications. A differential on-resistance of 18.6 mOmega ldr cm2 was achieved with a gate bias of 16 V, corresponding to a forward voltage drop of 5.3 V at 100 A/cm2, indicating strong conductivity modulation in the p-type drift region. A moderately doped current enhancement layer grown on the lightly doped drift layer effectively reduces the JFET resistance while maintaining a high carrier lifetime for conductivity modulation. The p-channel IGBT (p-IGBT) exhibits a transconductance that is 3times higher than that of the 12-kV n-channel SiC IGBTs. An inductive switching test was done at 1.5 kV and 0.55 A (~440 A/cm2) for the p-IGBTs, and a turn-on time of 40 ns and a turn-off time of ~2.8 mus were measured.