Semiconductor device and method of production

Claim 1

A method for making a semiconductor device comprising: forming a substrate of a first conductivity type; forming a well region of a second conductivity type in the substrate; forming an insulating film over the well region and the substrate; photoetching the insulating film to expose a portion of the substrate and a portion of the well region; forming a polysilicon layer of the second conductivity type on the exposed portion of the substrate and the insulating film which is over the substrate; forming a polysilicon layer of the first conductivity type on the exposed portion of the well region and the insulating film which is over the well region, such that a junction is formed where the polysilicon layer of the first conductivity type is directly connected to the polysilicon layer of the second conductivity type; heating the polysilicon layers such that the polysilicon layer of the second conductivity type is thermally diffused into the exposed portion of the substrate thereby forming a first diffusion region, and the polysilicon layer of the first conductivity type is thermally diffused into the exposed portion of the well region thereby forming a second diffusion region, and the first and second diffusion regions are separated by that portion of the insulating film which is directly below the junction of the polysilicon layers; forming a metal silcide film by sputtering over the surface; photoetching the metal silicide film, the polysilicon layer of the second conductivity type, the polysilicon layer of the first conductivity type, and the remaining insulating layer to form a first gate over the substrate, a second gate over the well region, and a wiring which includes the junction of the polysilicon layers and the first and second diffusion regions, and thereby exposing the substrate on both sides of the first gate and exposing the well region on both sides of the second gate; and injecting a high concentration of ions of the first conductivity type into the exposed ares of the substrate to form a first source and drain region in the substrate on either side of the first gate, and injecting a high concentration of ions of the second conductivity type into the exposed ares of the well region to form a second source and drain region in the well region on either side of the second gate.

Claim 2

A method for making a semiconductor device comprising: forming a substrate of a first conductivity type; forming a well region of a second conductivity type in the substrate; forming an insulating film over the well region and the substrate; photoetching the insulating film to expose a portion of the substrate and a portion of the well region; forming a polysilicon layer of the second conductivity type on the exposed portion of the substrate and the insulating film which is over the substrate; forming a polysilicon layer of the first conductivity type on the exposed portion of the well region and the insulating film which is over the well region, such that a junction is formed where the polysilicon layer of the first conductivity type is directly connected to the polysilicon layer of the second conductivity type; heating the polysilicon layers such that the polysilicon layer of the second conductivity type is thermally diffused into the exposed portion of the substrate thereby forming a first diffusion region, and the polysilicon layer of the first conductivity type is thermally diffused into the exposed portion of the well region thereby forming a second diffusion region, and the first and second diffusion regions are separated by that portion of the insulating film which is directly below the junction of the polysilicon layers; forming a metal silcide film by sputtering over the surface; photoetching the metal silicide film, the polysilicon layer of the second conductivity type, the polysilicon layer of the first conductivity type, and the remaining insulating layer to form a first gate over the substrate, a second gate over the well region, and a wiring which includes the junction of the polysilicon layers and the first and second diffusion regions, and thereby exposing the substrate on both sides of the first gate and exposing the well region on both sides of the second gate; and injecting a high concentration of ions of the first conductivity type into the exposed ares of the substrate to form a first source and drain region in the substrate on either side of the first gate, and injecting a high concentration of ions of the second conductivity type into the exposed ares of the well region to form a second source and drain region in the well region on either side of the second gate.