Patent Number: 7,102,234

Title: Method and structure for reduction of contact resistance of metal silicides using a metal-germanium alloy

Abstract: A method of reducing the contact resistance of metal silicides to the p+ silicon area or the n+ silicon area of the substrate comprising: (a) forming a metal germanium (Ge) layer over a silicon-containing substrate, wherein said metal is selected from the group consisting of Co, Ti, Ni and mixtures thereof; (b) optionally forming an oxygen barrier layer over said metal germanium layer; (c) annealing said metal germanium layer at a temperature which is effective in converting at least a portion thereof into a substantially non-etchable metal silicide layer, while forming a Si--Ge interlayer between said silicon-containing substrate and said substantially non-etchable metal silicide layer; and (d) removing said optional oxygen barrier layer and any remaining alloy layer. When a Co or Ti alloy is employed, e.g., Co--Ge or Ti--Ge, two annealing steps are required to provide the lowest resistance phase of those metals, whereas, when Ni is employed, a single annealing step forms the lowest resistance phase of Ni silicide.

Inventors: Cabral, Jr.; Cyril (Ossining, NY), Carruthers; Roy Arthur (Stormville, NY), Harper; James McKell Edwin (Yorktown Heights, NY), Lavoie; Christian (Ossining, NY), Roy; Ronnen Andrew (Ossining, NY), Wang; Yun Yu (Poughguag, NY)

Assignee: International Business Machines Corporation

International Classification: H01L 23/48 (20060101); H01L 29/40 (20060101)

Expiration Date: 9/05/02018