Process for fabricating a graded-channel MOS device

摘要

A process for fabricating a graded-channel MOS device includes the formation of a masking layer (16) on the surface of a semiconductor substrate (10) and separated from the surface by a gate oxide layer (12). A first doped region (22) is formed in a channel region (20) of the semiconductor substrate (10) using the masking layer (16) as a doping mask. A second doped region (24) is formed in the channel region (20) and extends from the principal surface (14) of the semiconductor substrate (10) to the first doped region (22). A gate electrode (34) is formed within an opening (18) in the masking layer (16) and aligned to the channel region (20). Upon removal of the masking layer (16) source and drain regions (36, 38) are formed in the semiconductor substrate (10) and aligned to the gate electrode (34).