Semiconductor device manufacturing method and semiconductor device manufactured thereby

Claim 1

A method of manufacturing semiconductor devices comprising: forming a gate insulating film on the surface of a semiconductor substrate, within which substrate lightly doped impurity regions are formed; forming a gate electrode on said gate insulating film; forming an impurity polysilicon layer on said substrate over said gate electrode, the density of the impurity introduced in said polysilicon being sufficiently high to increase the etching speed of said polysilicon layer; selectively removing said impurity polysilicon layer by anisotropic etching in order to leave polysilicon spacers flanked on the side surface of said gate electrode; introducing an impurity into said impurity regions by the use of said gate electrode and said spacers as masks in order to form heavily doped impurity regions in said lightly doped impurity regions, respectively; and removing said spacers by selective etching.

Claim 2

A method of manufacturing semiconductor devices comprising: forming a gate insulating film on the surface of a semiconductor substrate, within which substrate lightly doped impurity regions are formed; forming a gate electrode on said gate insulating film; forming an impurity polysilicon layer on said substrate over said gate electrode, the density of the impurity introduced in said polysilicon being sufficiently high to increase the etching speed of said polysilicon layer; selectively removing said impurity polysilicon layer by anisotropic etching in order to leave polysilicon spacers flanked on the side surface of said gate electrode; introducing an impurity into said impurity regions by the use of said gate electrode and said spacers as masks in order to form heavily doped impurity regions in said lightly doped impurity regions, respectively; and removing said spacers by selective etching.