Lateral uniformity in silicon recess etch

US8507386B2 · kind B2 · utility

Assignee

• TEXAS INSTRUMENTS INCORPORATED · US

Inventors

• David Gerald Farber · Plano, US
• Tom Lii · Plano, US

Key dates

• Filing date: Sep 13, 2010
• Grant date: Aug 13, 2013
• Expiry date: Jun 4, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D30/797
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method of etching recesses into silicon prior to formation of embedded silicon alloy source/drain regions. The recess etch includes a plasma etch component, using an etch chemistry of a primary fluorine-based or chlorine-based etchant, in combination with a similar concentration of hydrogen bromide. The concentration of both the primary etchant and the hydrogen bromide is relatively low; a diluent of an inert gas or oxygen is added to the reactive species. Loading effects on the undercut of the recess etch are greatly reduced, resulting in reduced transistor performance variation.