Design and optimization of linearly graded-doping junction termination extension for 3.3-kV-class IGBTs

A linearly graded-doping junction termination extension (LG-JTE) for 3.3-kV-class insulated gate bipolar transistors (IGBTs) was proposed and experimentally investigated. Unlike conventional multi-implantation utilizing more than one photolithography step, a single mask with injection window widths varied linearly away from the main junction to the edge was implemented in this proposed structure. Based on the simulation results, IGBTs with LG-JTE structures were successfully fabricated on the domestic process platform. The fabricated devices exhibited a 3.7 kV forward-blocking voltage, which is close to the theoretical value of an ideal parallel plane case. This is the first success in fabrication 3.3-kV-class IGBT in a domestic application.