Soft‐punch‐through buffer concept for 600–1200 V IGBTs

Abstract

A new soft-punch-through (SPT) buffer concept for 600-1200 V insulated-gate bipolar transistors (IGBTs) based on thin wafer technology is proposed. The new SPT structure employs an epitaxial layer for the lightly doped n-type drift region, which is grown on a thick starting material or substrate. The n-type substrate serves as the SPT buffer region. The doping concentration of both drift and buffer regions are comparably low with the buffer region having a higher doping level. The design options of this new concept are discussed based on experimental data and 1200 V IGBTs using the new buffer concept are compared to IGBTs employing previously published buffer technology.