Improvement Breakdown Voltage by a Using Crown-Shaped Gate

Abstract

In this paper, a crown-shaped trench gate formed by a sidewall spacer in insulated gate bipolar transistors (IGBT) is proposed to improve breakdown voltage. When a sidewall spacer is added to trench bottom corners, the electric field is distributed to the surface of the sidewall spacer and decreased to 48% peak value of the electric field. Thus, the sidewall spacer IGBT improved to 5% breakdown voltage. Another study proposed an additional oxide layer for trench bottom corners and improved breakdown voltage similar to the proposed IGBT. Previous studies have shown degradation in other electrical characteristics. However, this study shows a sidewall spacer IGBT that increases the current over 3% compared to a conventional trench IGBT when the applied gate voltage is under 4 V. Additionally, the turn-off loss characteristic is similar to conventional trench IGBT. Therefore, the breakdown voltage of the IGBT was improved while maintaining similar electrical properties to existing IGBTs through the crown-shaped gate.