Process for fabricating MOS semiconductor transistor

Abstract

A process for fabricating a MOS semiconductor transistor which includes a first oxide film on a semiconductor substrate and on a surface of a gate electrode formed on the semiconductor substrate with intervention of a gate insulating film, a nitride film on the first oxide film and a sidewall spacer of a second oxide film formed on a side of the gate electrode with intervention of the first oxide film and the nitride film, the process comprising the steps of: forming, on the nitride film, a photoresist mask which has an opening in a device formation region; implanting impurity ions through the nitride film and the first oxide film into the semiconductor substrate in a high concentration using the gate electrode, the sidewall spacer and the photoresist mask as a mask; selectively removing the sidewall spacer from the device formation region by wet etching; implanting impurity ions into the semiconductor substrate in a low concentration using the gate electrode and the photoresist mask as a mask, thereby forming an LDD structure; removing the photoresist mask; and thermally treating the resulting semiconductor substrate.

Dependencies are inferred from the claim text.