Patent ID: 8283231

Claim:
A method of forming a circuit comprising at least a first fin Field Effect Transistor (finFET) and a second finFET, the at least first and second finFETs being formed on a substrate and comprising a fin formed on the substrate, a first high density doped (HDD) region and a second high density doped (HDD) region formed in the substrate at longitudinal ends of the fin and at least one gate region formed adjacent the fin, where the drive strength of the first finFET is selected to be higher than the drive strength of the second finFET, by forming the first finFET with at least one of a first low density doped (LDD) extension region in the substrate extending from the first HDD region toward the gate region and a second low density doped (LDD) extension region in the substrate extending from the second HDD region toward the gate region; and the drive strength of the second finFET is selected to be lower than the drive strength of the first finFET by forming the second finFET with no LDD extension regions in the substrate or with only one of the first LDD extension region or the second LDD extension region.