New anode design concept of 600V thin wafer PT-IGBT with very low dose P-buffer and transparent P-emitter design concept of 600 V thin wafer PT-IGBT with very low dose P-buffer and transparent P-emitter

A 600 V thin wafer PT-IGBT (punch through insulated gate bipolar transistor) is proposed, having a new concept anode design. The proposed PT-IGBT has a very low dose p-type layer, named the 'p-buffer', between a transparent p-emitter and an n-buffer layer. This provides a practical design for easy fabrication without deteriorating the good feature of thin wafer PT-IGBTs. The n-buffer dose and p-emitter dose can be precisely controlled by the dose levels of the two ion implantations. This enables precise control of the p-emitter injection efficiency. An oscillation in the turn-off waveforms also disappears for the proposed PT-IGBT with p-buffer layer, because smooth turn-off is achieved by the small tail current. The total power loss is not affected by the small tail loss.