High switching speed trench diode for 1200V RC-IGBT based on the concept of Schottky Controlled injection (SC)

A novel trench diode for Reverse Conducting (RC) IGBTs is proposed. A Schottky Controlled injection (SC) concept is applied to the diode area of the RC-IGBT. The reverse recovery loss is reduced drastically by suppressing carrier injection from P+/P-anode and N+/N cathode without a significant increase in the turn-off power dissipation (Eoff) and the leakage current. The hole injection from the backside of the IGBT area suppresses the voltage ringing at diode reverse recovery condition, and it enables the reduction of the tail current by fabricating the N+/N cathode more finely. Moreover, high dynamic ruggedness is obtained under high current conditions because electric fields near the surface and the backside are relaxed by fixing impact ionization point to the bottom of the trench and injecting holes from the backside.