Patent ID: 7705407

Claim:
A device comprising: a substrate comprising impurities of a first conductivity, the substrate having a first surface and a second surface; a gate electrode formed over the first surface of the substrate; an lightly doped drain (LDD) region comprising low concentration impurities of a second conductivity doped in the substrate at a first side of the gate electrode; a drain region comprising high concentration impurities of the second conductivity doped in the LDD region; and a source region comprising high concentration impurities of the second conductivity doped in the substrate at a second side of the gate electrode; and spacers formed at sidewalls of the gate electrode, wherein one of the spacers includes a bottom surface contacting the LDD region, wherein the first surface of the substrate has a height that is greater than a height of the second surface of the substrate, and wherein the source and LDD regions are at least partially formed in a region at the second surface.