High germanium content silicon germanium fins

US9812530B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Karthik Balakrishnan · Houston, US
• John Bruley · Poughkeepsie, US
• Pouya Hashemi · White Plains, US
• Ali Khakifirooz · Los Altos, US
• John A. Ott · Marathon, US
• Alexander Reznicek · Troy, US

Key dates

• Filing date: Mar 13, 2016
• Grant date: Nov 7, 2017
• Expiry date: Mar 13, 2036

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/834
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Thermal condensation is employed to obtain a finned structure including strained silicon germanium fins having vertical side walls and a germanium content that may be high relative to silicon. A hard mask is used directly on a low-germanium content silicon germanium layer. The hard mask is patterned and fins are formed beneath the hard mask from the silicon germanium layer. Thermal condensation in an oxidizing ambient causes the formation of regions beneath the hard mask that have a high germanium content. The hard mask is trimmed to a target critical dimension. The regions beneath the hard mask and adjoining oxide material are subjected to reactive ion etch, resulting in the formation of high-germanium content fins with planar, vertically extending sidewalls.