Method for forming an integrated circuit

Abstract

A method is described for manufacturing an n-MOS semiconductor transistor. Recesses are formed in a semiconductor substrate adjacent a gate electrode structure. Silicon is embedded in the recesses via a selective epitaxial growth process. The epitaxial silicon is in-situ alloyed with substitutional carbon and in-situ doped with phosphorus. The silicon-carbon alloy generates a uniaxial tensile strain in the channel region between the source and drain, thereby increasing electron channel mobility and the transistor's drive current. The silicon-carbon alloy decreases external resistances by reducing contact resistance between source/drain and silicide regions and by reducing phosphorous diffusivity, thereby permitting closer placement of the transistor's source/drain and channel regions.

Dependencies are inferred from the claim text.