SELF-ALIGNED WELL IMPLANT FOR IMPROVING SHORT CHANNEL EFFECTS CONTROL, PARASITIC CAPACITANCE, AND JUNCTION LEAKAGE

摘要

A method of forming a self-aligned well implant for a transistor includes forming a patterned gate structure over a substrate, including a gate conductor, a gate dielectric layer and sidewall spacers, the substrate including an undoped semiconductor layer beneath the gate dielectric layer and a doped semiconductor layer beneath the undoped semiconductor layer; removing portions of the undoped semiconductor layer and the doped semiconductor layer left unprotected by the patterned gate structure, wherein a remaining portion of the undoped semiconductor layer beneath the patterned gate structure defines a transistor channel and a remaining portion of the doped semiconductor layer beneath the patterned gate structure defines the self-aligned well implant; and growing a new semiconductor layer at locations corresponding to the removed portions of the undoped semiconductor layer and the doped semiconductor layer, the new semiconductor layer corresponding to source and drain regions of the transistor.