Semiconductor device and method for manufacturing the same

Claim 2

A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first insulating film disposed on a major surface of the semiconductor substrate; a poly-Si film overlying the first insulating film, which film comprises: a non-single crystal type silicon region on said first insulating film, said non-single crystal type silicon region containing an impurity of a second conductivity type having a predetermined concentration level of less than 5×10 20 cm -3 ; a first poly-Si region on said non-single crystal type silicon region, said first poly-Si region containing an impurity of the second conductivity type having a first concentration level, said predetermined concentration level of said non-single crystal type silicon region being sufficiently less than said first concentration level to inhibit the diffusion of said first poly-Si regions's impurity into said first insulating film; and a second poly-Si region on said first poly-Si region, said second poly-Si region containing an impurity of the second conductivity type having a second concentration level; and a second insulating film on said second poly-Si region at the poly-Si film, said second concentration level of said poly-Si region being sufficiently less than said first concentration level of said first poly-Si region to inhibit the diffusion of said first poly-Si region's impurity into the second insulating film.

Claim 3

A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first insulating film disposed on a major surface of the semiconductor substrate; a poly-Si film overlying the first insulating film, which film comprises: a non-single crystal type silicon region on said first insulating film, said non-single crystal type silicon region containing an impurity of a second conductivity type having a predetermined concentration level; a first poly-Si region on said non-single crystal type silicon region, said first poly-Si region containing an impurity of the second conductivity type having a first concentration level, said predetermined concentration level of said non-single crystal type silicon region being sufficiently less than said first concentration level to inhibit the diffusion of said first poly-Si region's impurity into said first insulating film; and a second poly-Si region on said first poly-Si region, said second poly-Si region containing an impurity of the second conductivity type having a second concentration level of less than 5×10 20 cm -3 ; and a second insulating film on said second poly-Si region of the poly-Si film, said second concentration level of said poly-Si region being sufficiently less than said first concentration level of said first poly-Si region to inhibit the diffusion of said first poly-Si region's impurity into the second insulating film.

Claim 4

A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first insulating film disposed on a major surface of the semiconductor substrate; a poly-Si film overlying the first insulating film, which film comprises: a non-single crystal type silicon region on said first insulating film, said non-single crystal type silicon region containing an impurity of a second conductivity type having a predetermined concentration level; a first poly-Si region on said non-single crystal type silicon region, said first poly-Si region containing an impurity of the second conductivity type having a first concentration level, said predetermined concentration level of said non-single crystal type silicon region being sufficiently less than said first concentration level to inhibit the diffusion of said first poly-Si region's impurity into said first insulating film; and a second poly-Si region on said first poly-Si region, said second poly-Si region containing an impurity of the second conductivity type having a second concentration level of less than 5×10 20 cm -3 ; and a second insulating film on said second poly-Si region of the poly-Si film, said second concentration level of said poly-Si region being sufficiently less than said first concentration level of said first poly-Si region to inhibit the diffusion of said first poly-Si region's impurity into the second insulating film.

Claim 5

A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first insulating film disposed on a major surface of the semiconductor substrate; a poly-Si film overlying the first insulating film, which film comprises: a non-single crystal type silicon region on said first insulating film, said non-single crystal type silicon region containing an impurity of a second conductivity type having a predetermined concentration level of less than 5×10 20 cm -3 ; a first poly-Si region on said non-single crystal type silicon region, said first poly-Si region containing an impurity of the second conductivity type having a first concentration level of greater than 5×10 20 cm -3 , said predetermined concentration level of said non-single crystal type silicon region being sufficiently less than said first concentration level to inhibit the diffusion of said first poly-Si region's impurity into said first insulating film; and a second poly-Si region on said first poly-Si region, said second poly-Si region containing an impurity of the second conductivity type having a second concentration level of; and a second insulating film on said second poly-Si region of the poly-Si film, said second concentration level of said poly-Si region being sufficiently less than said first concentration level of said first poly-Si region to inhibit the diffusion of said first poly-Si region's impurity into the second insulating film.

Claim 6

A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first insulating film disposed on a major surface of the semiconductor substrate; a poly-Si film overlying the first insulating film, which film comprises: a non-single crystal type silicon region on said first insulating film, said non-single crystal type silicon region containing an impurity of a second conductivity type having a predetermined concentration level of less than 5×10 20 cm -3 ; a first poly-Si region on said non-single crystal type silicon region, said first poly-Si region containing an impurity of the second conductivity type having a first concentration level of greater than 5×10 20 cm -3 , said predetermined concentration level of said non-single crystal type silicon region being sufficiently less than said first concentration level to inhibit the diffusion of said first poly-Si region's impurity into said first insulating film; and a second poly-Si region on said first poly-Si region, said second poly-Si region containing an impurity of the second conductivity type having a second concentration level of; and a second insulating film on said second poly-Si region of the poly-Si film, said second concentration level of said poly-Si region being sufficiently less than said first concentration level of said first poly-Si region to inhibit the diffusion of said first poly-Si region's impurity into the second insulating film.