A new punch-through IGBT having a new n-buffer layer

Insulated gate bipolar transistors (IGBTs) based on the non-punch-through (NPT) design approach exhibit excellent safe operating area (SOA) and short-circuit endurance, a positive temperature coefficient of on-state voltage over the operating current range, and low silicon cost. These merits have supported the development and commercialization of NPT IGBTs above the 1200-V class. However, the need for quite thin silicon to obtain competitive on-state losses at 1200-V and below classes has hindered the use of the NPT approach in this area. A new punch-through (PT) IGBT has been developed which exhibits the merits of the NPT approach, rugged SOA and short-circuit endurance, while also having a better tradeoff relation between on-state voltage and turn-off loss than either existing NPT or third-generation PT IGBTs.