Memory cell structure of a mask programmable read only memory with ion-implantation stopper films

A semiconductor structure comprising:

• a semiconductor active region of a first conductivity type including a channel region and a non-channel 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;
• and
• ion-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
• wherein a plurality of said ion-implantation stopper films extend at least in opposite sides of said control electrode and also extend at least in substantially the same level as said control electrode
• wherein a plurality of said control electrodes are provided, and said ion-implantation stopper films extend at least in apertures between said control electrodes,
• wherein said ion-implantation stopper films extend not only in said apertures between said control electrodes but also within grooves formed in said semiconductor active region and positioned under said apertures, so that lower parts of said ion-implantation stopper films are positioned in opposite sides of said first diffusion region.

A semiconductor structure comprising:

• a semiconductor active region of a first conductivity type including a channel region and a non-channel 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;
• and
• ion-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
• wherein a plurality of said ion-implantation stopper films extend at least in opposite sides of said control electrode and also extend at least in substantially the same level as said control electrode
• wherein a plurality of said control electrodes are provided, and said ion-implantation stopper films extend at least in apertures between said control electrodes,
• wherein said ion-implantation stopper films are separated by a passivation film from said control electrodes.

A semiconductor structure comprising:

• a semiconductor active region of a first conductivity type including a channel region and a non-channel 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;
• and
• ion-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,
• wherein said material of said ion-implantation stopper film is a conductive material which comprises at least one element having a large mass number.

A semiconductor memory cell structure comprising:

• a semiconductor substrate having an active region of a first conductivity type, and said active region including a channel region and a non-channel region surrounding said channel region;
• source and drain diffusion regions in parts of said non-channel region in said active region;
• a gate insulation film extending over at least said channel region;
• a plurality of gate electrodes on said insulation film;
• at least a first diffusion region of said first conductivity type occupying said channel region for defining a threshold voltage of said channel region;
• and
• a plurality of ion-implantation stopper films, each of said stopper films covering at least parts of said non-channel region in opposite side regions of said gate electrode but not covering at least a center region of said gate electrode, and said ion-implantation stopper film being made of a material preventing ions from penetrating said ion-implantation stopper film in an ion-implantation for forming said first diffusion region, the ion-implantation stopper films being wholly located overlying a corresponding source or drain diffusion region.

A semiconductor structure comprising:

• a semiconductor active region of a first conductivity type including a channel region and a non-channel 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;
• and
• at least an ion-implantation stopper film extending in at least a part of said non-channel region and also at least lying a below level to said control electrode but not underlying said control electrode, and lower parts of said ion-implantation stopper film being positioned in opposite sides of said first diffusion region, and said ion-implantation stopper film being made of a material preventing ions from penetrating said ion-implantation stopper film in an ion-implantation for forming said first diffusion region.