Trench MIS device with active trench corners and thick bottom oxide

US6849898B2 · kind B2 · utility

Assignee

• SILICONIX INCORPORATED · US

Inventors

• Mohamed N. Darwish · Campbell, US
• Frederick P. Giles · San Jose, US
• Kam Hong Lui · Santa Clara, US
• Kuo-In Chen · Los Altos, US
• Kyle Terrill · Santa Clara, US

Key dates

• Filing date: Aug 10, 2001
• Grant date: Feb 1, 2005
• Expiry date: Aug 10, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/157
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Trench MOSFETs including active corner regions and a thick insulative layer at the bottom of the trench are disclosed, along with methods of fabricating such MOSFETs. In an exemplary embodiment, the trench MOSFET includes a thick insulative layer centrally located at the bottom of the trench. A thin gate insulative layer lines the sidewall and a peripheral portion of the bottom surface of the trench. A gate fills the trench, adjacent to the gate insulative layer. The gate is adjacent to the sides and top of the thick insulative layer. The thick insulative layer separates the gate from the drain conductive region at the bottom of the trench yielding a reduced gate-to-drain capacitance making such MOSFETs suitable for high frequency applications.