Novel Low Turn-Off Loss Trench-Gate FS-IGBT With a Hybrid $p^{{+}}/{n}$ Collector Structure

A trench-gate field stop insulated gate bipolar transistor (TFS-IGBT) with a novel hybrid p
⁺
/n collector structure is proposed to enhance the trade-off relationship between the on-state voltage drop (Von) and the turn-off energy loss (E
_off
). The proposed hybrid collector structure consists of a p
⁺
/n layer between the p± collector and the field stop layer. During turn-on, the p
⁺
regions in the hybrid p
⁺
/n layer provide high carrier injection efficiency. During turn-off transient, the n-regions in the hybrid p
⁺
/n collector provide fast carrier extraction paths for holes. 2-D numerical simulations comparing a conventional TFS-IGBT, an injection efficiency controlled IGBT with the proposed hybrid p
⁺
/n collector TFS-IGBT (HC-IGBT) having similar device structures show that for a 1.2 kV rating and with Von at 1.5 V, the HC-IGBT has an advantage in Eoff reduction by 69% and 22%, respectively. Finally, backside mask alignment is not needed for fabricating the proposed hybrid p
⁺
/n collector structure.