Scaling Design Effects on Surface Buffer IGBT Characteristics

Scaling design effects on surface buffer (SB) insulated gate bipolar transistor (IGBT) is analyzed not only for power loss reduction but also for switching controllability and robustness using TCAD simulation. Although the scaling design improves turn-off loss and on-state voltage drop Vce(sat) trade-off due to injection enhancement (IE) effect, turn-on surge current is increased by the enhancement of negative gate capacitance due to thin gate oxide. Dual gate control improves turn-on switching controllability by hole current path control. Short circuit robustness is improved by the scaling design, because the saturation current is decreased with the scaling design due to pinch-off of the n-MOS channel. From these results, the scaling design is effective in improving the SB-IGBT characteristics including high robustness.