Electrically isolated SiGe fin formation by local oxidation

US9093326B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Kangguo Cheng · Schenectady, US
• Hong He · Schenectady, US
• Chiahsun Tseng · Wynantskill, US
• Yunpeng Yin · Guilderland, US

Key dates

• Filing date: Oct 21, 2013
• Grant date: Jul 28, 2015
• Expiry date: Oct 21, 2033

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D30/611

Abstract

A silicon germanium alloy layer is formed on a semiconductor material layer by epitaxy. An oxygen impermeable layer is formed on the silicon germanium alloy layer. The oxygen impermeable layer and the silicon germanium alloy layer are patterned to form stacks of a silicon germanium alloy fin and an oxygen impermeable cap. A shallow trench isolation structure is formed by deposition, planarization, and recessing or an oxygen permeable dielectric material. An oxygen impermeable spacer is formed around each stack of a silicon germanium alloy fin and an oxygen impermeable cap. A thermal oxidation process is performed to convert a lower portion of each silicon germanium alloy fin into a silicon germanium oxide. During the thermal oxidation process, germanium atoms diffuse into unoxidized portions of the silicon germanium alloy fins to increase the germanium concentration therein.