Power Loss Reduction of N-Channel 10-kV SiC IGBTs With Box Cell Layout

Abstract

We investigated the power loss reduction of an n-channel 4H-silicon carbide (SiC) insulated-gate bipolar transistor (IGBT) with a blocking voltage of 10 kV by utilizing a box cell layout, which can enhance the conductivity modulation, instead of a conventional string cell layout. The box cell layout significantly reduced the on-voltage of SiC IGBTs, which are a 35% and 29% reduction in the specific differential on-resistance at 25 $^{\circ}$ C and 150 $^{\circ}$ C, respectively. Although enhancing the conductivity modulation should increase the turn-off loss, it has increased slightly, by 10% at 25 $^{\circ}$ C and by 5% at 150 $^{\circ}$ C with a load current of 250 A/cm $^{\text{2}}$ because the box cell layout can enhance the stored carrier, particularly near the emitter in the on-state. In contrast to the turn-off loss, turn-on loss was reduced by the box cell layout due to the enhancement of electron injection from the emitter, resulting in a lower total switching loss in comparison to a string-layout device. A lower on-voltage and switching loss of SiC IGBTs have both been achieved as a result of the box cell layout enhancing conductivity modulation enhancement.