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

We propose 600V new thin wafer PT (Punch Through) IGBT having a new concept of anode design. This proposed PT-IGBT has a very low dose p-type layer, called p-buffer, between a transparent p-emitter (anode) and an n-buffer layer. This provides a practical design for easy fabrication without deteriorating the good feature of the thin wafer PT-IGBTs. The n-buffer dose and the p-emitter dose can be precisely controlled by the doses of the two ion implantations. This is great merit in 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 a smooth turn-off is achieved by a small tail current. The total power loss is not affected by the small tail loss.