Method for fabricating a semiconductor device by controlled diffusion between adjacent layers

Claim 1

A method for fabricating a semiconductor device which comprises the steps of forming an impurity-containing layer over a certain region of a substrate, forming a semiconductor layer over another region of the substrate and contiguous to the impurity-containing layer, and doping the impurity contained in the impurity-containing layer into the semiconductor layer to selectively form an impurity-containing semiconductor region, contiguous to the impurity-containing layer, and an impurity-free semiconductor region in the semiconductor layer, wherein said impurity-containing layer and the impurity-free semiconductor region in the semiconductor layer are spaced from each other by said impurity-containing semiconductor region.

Claim 2

A method for fabricating a semiconductor device which comprises the steps of forming an impurity-containing layer over a certain region of a substrate, forming a semiconductor layer over another region of the substrate and contiguous to the impurity-containing layer, and doping the impurity contained in the impurity-containing layer into the semiconductor layer to selectively form an impurity-containing semiconductor region, contiguous to the impurity-containing layer, and an impurity-free semiconductor region in the semiconductor layer, wherein said impurity-containing layer and the impurity-free semiconductor region in the semiconductor layer are spaced from each other by said impurity-containing semiconductor region.

Claim 10

A method for fabricating a semiconductor device which comprises the steps of forming an oxide film on the surface of a semiconductor substrate, forming an impurity-containing layer selectively on a certain region of the oxide film, forming a semiconductor layer on another region of the oxide film, and contiguous to the impurity-containing layer, and doping the impurity contained in the impurity-containing layer selectively into the semiconductor layer to form an impurity-containing semiconductor region contiguous to the impurity-containing layer and to form an impurity-free semiconductor region in the semiconductor layer, wherein the impurity-free semiconductor region of the semiconductor layer and the impurity-containing layer are spaced from each other by said impurity-containing semiconductor region.

Claim 11

A method for fabricating a semiconductor device which comprises the steps of forming an oxide film on the surface of a semiconductor substrate, forming an impurity-containing layer selectively on a certain region of the oxide film, forming a semiconductor layer on another region of the oxide film, and contiguous to the impurity-containing layer, and doping the impurity contained in the impurity-containing layer selectively into the semiconductor layer to form an impurity-containing semiconductor region contiguous to the impurity-containing layer and to form an impurity-free semiconductor region in the semiconductor layer, wherein the impurity-free semiconductor region of the semiconductor layer and the impurity-containing layer are spaced from each other by said impurity-containing semiconductor region.

Claim 14

A method for the preparation of semiconductor devices, which comprises the steps of forming an impurity-containing layer selectively over a certain region of a semiconductor substrate, forming a first layer over another region of the semiconductor substrate and contiguous to the impurity-containing layer, and doping the impurity contained in the impurity-containing layer selectively into the first layer to form an impurity-containing region contiguous to the impurity-containing layer and an impurity-free region, wherein said impurity-containing layer and said impurity-free region are spaced from each other by said impurity-containing region.

Claim 15

A method for the preparation of semiconductor devices, which comprises the steps of forming an impurity-containing layer selectively over a certain region of a semiconductor substrate, forming a first layer over another region of the semiconductor substrate and contiguous to the impurity-containing layer, and doping the impurity contained in the impurity-containing layer selectively into the first layer to form an impurity-containing region contiguous to the impurity-containing layer and an impurity-free region, wherein said impurity-containing layer and said impurity-free region are spaced from each other by said impurity-containing region.

Claim 16

A method for fabricating a semiconductor device, which comprises steps of forming an impurity-containing region over a substrate, forming a coating composed mainly of silicon so that said coating covers at least a part of the impurity-containing region, diffusing the impurity contained in the impurity-containing layer into the coating adjoining to the impurity-containing layer to form an impurity-containing portion in said coating, heat-oxidizing said coating composed mainly of silicon to form an oxide film on the surface of the impurity-containing portion of said coating and also form on the surface of the impurity-free portion of said coating an oxide film having a thickness smaller than the thickness of the oxide film formed on the surface of the impurity-containing portion, and selectively removing the impurity-free coating of the impurity-free portion while leaving the impurity-containing coating of the impurity-containing portion.

Claim 17

A method for fabricating a semiconductor device, which comprises steps of forming an impurity-containing region over a substrate, forming a coating composed mainly of silicon so that said coating covers at least a part of the impurity-containing region, diffusing the impurity contained in the impurity-containing layer into the coating adjoining to the impurity-containing layer to form an impurity-containing portion in said coating, heat-oxidizing said coating composed mainly of silicon to form an oxide film on the surface of the impurity-containing portion of said coating and also form on the surface of the impurity-free portion of said coating an oxide film having a thickness smaller than the thickness of the oxide film formed on the surface of the impurity-containing portion, and selectively removing the impurity-free coating of the impurity-free portion while leaving the impurity-containing coating of the impurity-containing portion.

Claim 22

A method for fabricating a semiconductor devices, which comprises steps of forming a first film containing an impurity and being comprised mainly of silicon on a part of the surface of a substrate, forming a second film comprised mainly of silicon on the surface of the substrate to cover the first film, performing a heat treatment to diffuse the impurity contained in the first film into the adjoining second film and form a region containing the impurity at a part of the second film, and heat-oxidizing parts of said first and second films to electrically separate at least the first film from the second film by an oxide film formed by the heat oxidation.

Claim 23

A method for fabricating a semiconductor devices, which comprises steps of forming a first film containing an impurity and being comprised mainly of silicon on a part of the surface of a substrate, forming a second film comprised mainly of silicon on the surface of the substrate to cover the first film, performing a heat treatment to diffuse the impurity contained in the first film into the adjoining second film and form a region containing the impurity at a part of the second film, and heat-oxidizing parts of said first and second films to electrically separate at least the first film from the second film by an oxide film formed by the heat oxidation.

Claim 25

A method for fabricating a semiconductor devices, which comprises steps of forming an impurity-containing region containing boron as an impurity over a substrate, forming a film composed mainly of silicon to cover at least a part of the surface of said impurity-containing region, diffusing boron contained in the impurity-containing region into the adjoining coating to form a boron-containing portion in said coating, and carrying out such an etching treatment that the coating is removed from the boron-free portion while leaving at least a part of the coating of said boron-containing portion.

Claim 26

A method for fabricating a semiconductor devices, which comprises steps of forming an impurity-containing region containing boron as an impurity over a substrate, forming a film composed mainly of silicon to cover at least a part of the surface of said impurity-containing region, diffusing boron contained in the impurity-containing region into the adjoining coating to form a boron-containing portion in said coating, and carrying out such an etching treatment that the coating is removed from the boron-free portion while leaving at least a part of the coating of said boron-containing portion.