Semiconductor device and its manufacturing method

Claim 1

A method for manufacturing a semiconductor device, comprising: forming an impurity diffusion layer in a semiconductor substrate, forming two gates separated by a predetermined interval over a surface of said substrate and forming a first insulating layer on each of said gates; forming a first polysilicon conductive layer on said first insulating layer, said first polysilicon conductive layer being connected to said impurity diffusion layer and extending on said first insulating layer a distance greater than said predetermined interval; forming a second insulating layer over an entire area of said surface of said substrate on which said gates are formed; forming in said second insulating layer a hole having a diameter larger than said predetermined interval between said gates; forming in said hole, by a selective epitaxial method, a second polysilicon conductive layer connected to said first polysilicon conductive layer, said selective epitaxial method being performed within a furnace of a chemical vapor deposition apparatus; and forming within said furnace by polysilicon deposition a third polysilicon conductive layer connected to said second polysilicon conductive layer, wherein said forming of the second polysilicon conductive layer and the third polysilicon conductive layer is continuously performed in a same furnace without exposure to an atmosphere outside the furnace and absent formation of an oxide film between the second and third polysilicon conductive layers.

Claim 2

A method for manufacturing a semiconductor device, comprising: forming an impurity diffusion layer in a semiconductor substrate, forming two gates separated by a predetermined interval over a surface of said substrate and forming a first insulating layer on each of said gates; forming a first polysilicon conductive layer on said first insulating layer, said first polysilicon conductive layer being connected to said impurity diffusion layer and extending on said first insulating layer a distance greater than said predetermined interval; forming a second insulating layer over an entire area of said surface of said substrate on which said gates are formed; forming in said second insulating layer a hole having a diameter larger than said predetermined interval between said gates; forming in said hole, by a selective epitaxial method, a second polysilicon conductive layer connected to said first polysilicon conductive layer, said selective epitaxial method being performed within a furnace of a chemical vapor deposition apparatus; and forming within said furnace by polysilicon deposition a third polysilicon conductive layer connected to said second polysilicon conductive layer, wherein said forming of the second polysilicon conductive layer and the third polysilicon conductive layer is continuously performed in a same furnace without exposure to an atmosphere outside the furnace and absent formation of an oxide film between the second and third polysilicon conductive layers.

Claim 9

A method for manufacturing a dynamic random access memory device, comprising: forming an impurity diffusion layer in a semiconductor substrate, forming two gates separated by a predetermined interval over a surface of said substrate to produce a field effect transistor for switching between bit lines and cells, with said gates being separated by a predetermined interval and forming an insulating layer on each of said gates; forming a first polysilicon conductive layer on said first insulating layer, said first polysilicon conductive layer being connected to said impurity diffusion layer and extending on said first insulating layer a distance greater than said predetermined interval; forming a second insulating layer over an entire area of the surface of said substrate on which said gates are formed; forming in said second insulating layer a hole having a diameter larger than said predetermined interval between said gates; forming in said hole, by a selective epitaxial growth method, a second polysilicon conductive layer connected to said first polysilicon conductive layer, said selective epitaxial growth method being performed within a furnace of a chemical vapor deposition apparatus; and forming within said furnace by polysilicon deposition a third polysilicon conductive layer, as a bit line of said dynamic random access memory device, connected to said second polysilicon conductive layer, wherein said forming of the second polysilicon conductive layer and the third polysilicon conductive layer is continuously performed in a same furnace without exposure to an atmosphere outside the furnace and absent formation of an oxide film between the second and third polysilicon conductive layers.

Claim 10

A method for manufacturing a dynamic random access memory device, comprising: forming an impurity diffusion layer in a semiconductor substrate, forming two gates separated by a predetermined interval over a surface of said substrate to produce a field effect transistor for switching between bit lines and cells, with said gates being separated by a predetermined interval and forming an insulating layer on each of said gates; forming a first polysilicon conductive layer on said first insulating layer, said first polysilicon conductive layer being connected to said impurity diffusion layer and extending on said first insulating layer a distance greater than said predetermined interval; forming a second insulating layer over an entire area of the surface of said substrate on which said gates are formed; forming in said second insulating layer a hole having a diameter larger than said predetermined interval between said gates; forming in said hole, by a selective epitaxial growth method, a second polysilicon conductive layer connected to said first polysilicon conductive layer, said selective epitaxial growth method being performed within a furnace of a chemical vapor deposition apparatus; and forming within said furnace by polysilicon deposition a third polysilicon conductive layer, as a bit line of said dynamic random access memory device, connected to said second polysilicon conductive layer, wherein said forming of the second polysilicon conductive layer and the third polysilicon conductive layer is continuously performed in a same furnace without exposure to an atmosphere outside the furnace and absent formation of an oxide film between the second and third polysilicon conductive layers.