Patent ID: 7064039

Claim:
A method for forming a localized halo structure in a semiconductor substrate of a semiconductor device, comprising: providing a gate structure over the semiconductor substrate; implanting a dopant material at an angle around the gate structure to form a halo structure in a source/drain region of the semiconductor substrate and underlying a portion of the gate structure; forming a trench in the source/drain region of the semiconductor substrate, thereby removing at least a portion of the halo structure in the source/drain region; and forming a semiconductor material layer in the trench, comprising: forming an intrinsic silicon layer in a bottom portion of the trench; and forming a doped silicon layer in a top portion of the trench overlying the intrinsic silicon layer, wherein the trench is substantially filled having a generally undoped region in a bottom portion of the trench and a generally doped region in a top portion of the trench.