Patent ID: 7429769

Claim:
A recessed channel field effect transistor device comprising: a semiconductor substrate comprising an active silicon layer; a gate dielectric layer formed upon the semiconductor substrate; a gate electrode formed upon the gate dielectric layer to define a channel region within the active silicon layer of the semiconductor substrate; a pair of lightly doped extension regions formed into the active silicon layer of the semiconductor substrate separated by the gate electrode and the channel region; a pair of source/drain regions formed into the active silicon layer ot the semiconductor substrate and separated by the channel region and the pair of lightly doped extension region, wherein the pair of source/drain regions has a thickness substantially the same as that of the active silicon layer; and a pair of spacer adjoining a pair of sidewalls of the gate electrode and partially covering the top surfaces of the pair of source/drain regions; Wherein: the channel region and the pair of lightly doped extension regions are recessed within the active silicon layer of the semiconductor substrate with respect to the pair of source/drain regions; and the pair of lightly droped extension regions has a different dopant concentration in comparison with the pair of source/drain regions.