Thicker oxide formation at the trench bottom by selective oxide deposition

US6709930B2 · kind B2 · utility

Assignee

• SILICONIX INCORPORATED · US

Inventors

• Ben Chan · Holmdel, US
• Kam Hong Lui · Santa Clara, US
• Christiana Yue · Milpitas, US
• Ronald Wong · Campbell, US
• David Chang · Saratoga, US
• Frederick P. Giles · San Jose, US
• Kyle Terrill · Santa Clara, US
• Mohamed N. Darwish · Campbell, US
• Deva Pattanayak · Saratoga, US
• Robert Xu · Fremont, US
• Kuo-In Chen · Los Altos, US

Key dates

• Filing date: Jun 21, 2002
• Grant date: Mar 23, 2004
• Expiry date: Jun 21, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/516

Abstract

A trench MOSFET is formed by creating a trench in a semiconductor substrate, then forming a barrier layer over a portion of the side wall of the trench. A thick insulating layer is deposited in the bottom of the trench. The barrier layer is selected such that the thick insulating layer deposits in the bottom of the trench at a faster rate than the thick insulating layer deposits on the barrier layer. Embodiments of the present invention avoid stress and reliability problems associated with thermal growth of insulating layers, and avoid problems with control of the shape and thickness of the thick insulating layer encountered when a thick insulating layer is deposited, then etched to the proper shape and thickness.