Patent ID: 7736956

Claim:
A method for making a semiconductor device, comprising: forming a gate dielectric on a second semiconductor layer on an insulator layer that is on a first semiconductor layer; forming a metal gate electrode on the gate dielectric, the metal gate electrode having a first side and a second side; removing portions of the metal gate electrode on the first side and the second side to form curved lateral undercuts extending into a center of the metal gates thickness and tapering off towards a top and a bottom surface of the metal gate said curved lateral undercuts having a depth laterally measured from an outermost edge of the metal gate to a greatest depth of the lateral undercut; forming source/drain regions of the second semiconductor layer on the first and second side of the metal gate electrode, the source/drain regions having extensions a distance beneath the metal gate electrode; and wherein the depth of the lateral undercuts are at least about one-fourth the distance of the source/drain region extensions.