Patent ID: 8975703
Filing Date: 2015-03-10
Classification: H01L

Abstract:
1. An MOS transistor comprising: a semiconductor substrate; a gate structure disposed on a surface of the semiconductor substrate, wherein the semiconductor substrate includes a first groove on one side of the gate structure and a second groove on an other side of the gate structure, and wherein the first groove has a sidewall adjacent to a channel region and perpendicular to the surface of the semiconductor substrate and the second groove has a sidewall protruding into the channel region under the gate structure, and wherein the first groove has a bottom surface directly connected and perpendicular to the sidewall adjacent to the channel region; and a stressing material disposed in each of the first groove and the second groove, wherein the stressing material is silicon carbide having a carbon concentration in the protruded second groove greater than in the first groove, or is silicon germanium having a germanium concentration in the protruded second groove greater than in the first groove.