Embedded silicon germanium source drain structure with reduced silicide encroachment and contact resistance and enhanced channel mobility

US8120120B2 · kind B2 · utility

Assignee

• GlobalFoundries Inc. · KY

Inventors

• Frank (Bin) Yang · Mahwah, US
• Johan W. Weijtmans · Hopewell Junction, US
• Scott Luning · San Francisco, US

Key dates

• Filing date: Sep 17, 2009
• Grant date: Feb 21, 2012
• Expiry date: Jan 13, 2030

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/021

Abstract

Semiconductor devices with embedded silicon germanium source/drain regions are formed with enhanced channel mobility, reduced contact resistance, and reduced silicide encroachment. Embodiments include embedded silicon germanium source/drain regions with a first portion having a relatively high germanium concentration, e.g., about 25 to about 35 at. %, an overlying second portion having a first layer with a relatively low germanium concentration, e.g., about 10 to about 20 at. %, and a second layer having a germanium concentration greater than that of the first layer. Embodiments include forming additional layers on the second layer, each odd numbered layer having relatively low germanium concentration, at. % germanium, and each even numbered layer having a relatively high germanium concentration. Embodiments include forming the first region at a thickness of about 400 Å to 28 about 800 Å, and the first and second layers at a thickness of about 30 Å to about 70 Å.