Trench schottky barrier diode with differential oxide thickness

US8143655B2 · kind B2 · utility

Assignee

• International Rectifier Corporation · US

Inventor

• Davide Chiola · Chino, US

Key dates

• Filing date: Oct 11, 2007
• Grant date: Mar 27, 2012
• Expiry date: Oct 11, 2027

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/963

Abstract

A fabrication process for a trench Schottky diode with differential oxide thickness within the trenches includes forming a first nitride layer on a substrate surface and subsequently forming a plurality of trenches in the substrate including, possibly, a termination trench. Following a sacrificial oxide layer formation and removal, sidewall and bottom surfaces of the trenches are oxidized. A second nitride layer is then applied to the substrate and etched such that the second nitride layer covers the oxide layer on the trench sidewalls but exposes the oxide layer on the trench bottom surfaces. The trench bottom surfaces are then re-oxidized and the remaining second nitride layer then removed from the sidewalls, resulting in an oxide layer of varying thickness being formed on the sidewall and bottom surfaces of each trench. The trenches are then filled with a P type polysilicon, the first nitride layer removed, and a Schottky barrier metal applied to the substrate surface.