Patent ID: 7816274

Claim:
A method for fabricating strained-channel semiconductor devices having a varying transistor population density, the method comprising: providing a substrate having a first region including transistors and a second region including transistors, wherein the first region is more densely populated with transistors than the second region; forming a stress-inducing region in proximity to a channel region of the transistors; and forming sidewall spacers on the transistors to selectively space the stress-inducing regions in the first and second substrate regions away from the channel regions of the transistors, wherein the sidewall spacers in the second region have a lateral dimension that is larger than a lateral dimension of the sidewall spacers in the first region, such that the stress-inducing regions are selectively spaced away from the channel regions of the transistors so as to adjust a drive current of the transistors in more densely populated regions to be substantially the same as a drive current of the transistors in less densely populated regions of the substrate.