Patent ID: 8368151

Claim:
A semiconductor device comprising: a first metal oxide semiconductor (MOS) transistor and a second MOS transistor commonly formed on a main surface of a semiconductor substrate of a first conductivity type, wherein the first MOS transistor includes: source and drain regions of a second conductivity type; a gate electrode provided on the main surface between the source and drain regions interposing a gate insulating film; a channel diffusion region of the first conductivity type formed on the semiconductor substrate below the gate electrode; lightly doped drain (LDD) regions of the second conductivity type formed on the semiconductor substrate between the channel diffusion region and the source and drain regions and having an impurity concentration lower than those of the source and drain regions; and halo diffusion regions of the first conductivity type formed just below the LDD regions and in portions of the source and drain regions, wherein the second MOS transistor includes: source and drain regions of the second conductivity type; a gate electrode provided on a gate insulating film on the main surface between the source and drain regions; a channel diffusion region of the second conductivity type formed on the semiconductor substrate below the gate electrode; and LDD regions of the second conductivity type formed on the semiconductor substrate between the channel diffusion region and the source and drain regions, wherein the second MOS transistor includes no halo diffusion region of the first conductivity type just below the LDD regions and in portions of the source and drain regions, and wherein the first conductivity type is a different conductivity type than the second conductivity type.