A novel trench IGBT with a rectangular oxide beneath the trench gate

Abstract

General IGBTs are of two basic types, the planar IGBT and the trench IGBT. The trench IGBT has certain advantages when compared with the planar IGBT, such as a lower on-state voltage drop and a smaller cell pitch, but it also has a disadvantage in its lower breakdown voltage. The lower breakdown voltage is caused by the electric field being concentrated in a corner along the bottom of the trench gate. Therefore in this paper we propose a new trench IGBT structure that is designed to offer improved breakdown voltage.