Patent ID: 6204540
Filing Date: 2001-03-20
Classification: H01L

Abstract:
A semiconductor structure comprising:a semiconductor active region of a first conductivity type including a channel region and a non-channel diffusion region surrounding said channel region;an insulation film extending over at least said channel region;at least a control electrode on said insulation film for applying an electric field to said channel region;at least a first diffusion region of said first conductivity type occupying said channel region for defining a threshold voltage of said channel region; andion-implantation stopper films, each of said ion-implantation stopper films covering at least a part of said non-channel region but not covering at least a center region of said control electrode, and said ion-implantation stopper films being made of a material preventing ions from penetrating said ion-implantation stopper film in an ion-implantation for forming said first diffusion region and said ion-implantation stopper films each comprising a single planar upper surface, said ion-implantation stopper films being wholly located overlying a corresponding non-channel diffusion region surrounding said channel region.