Method of forming a stacked semiconductor device wherein semiconductor layers and insulating films are sequentially stacked and forming openings through such films and etchings using one of the insulating films as a mask

Claim 1

A method of manufacturing a semiconductor device, comprising the steps of: after a first insulating film, a first semiconductor layers of a second conductivity type, and a second insulating film are sequentially stacked on a substrate of a first conductivity type, forming a first opening to reach a surface of said substrate; after a second semiconductor layer of the second conductivity type and a third insulating film are sequentially stacked on the entire surface of the resultant structure including said first opening, etching back said third insulating film by anisotropic etching to be left on a side wall of said second semiconductor layer, and removing said second semiconductor layer on said substrate by isotropic etching using said third insulating film as a mask to expose a part of said substrate, thereby forming a second opening; forming a first single-crystal semiconductor layer of the second conductivity type in said second opening using a molecular beam epitaxial selective growth method; and forming a third semiconductor layer of the first conductivity type on said first single-crystal semiconductor layer.

Claim 2

A method of manufacturing a semiconductor device, comprising the steps of: after a first insulating film, a first semiconductor layers of a second conductivity type, and a second insulating film are sequentially stacked on a substrate of a first conductivity type, forming a first opening to reach a surface of said substrate; after a second semiconductor layer of the second conductivity type and a third insulating film are sequentially stacked on the entire surface of the resultant structure including said first opening, etching back said third insulating film by anisotropic etching to be left on a side wall of said second semiconductor layer, and removing said second semiconductor layer on said substrate by isotropic etching using said third insulating film as a mask to expose a part of said substrate, thereby forming a second opening; forming a first single-crystal semiconductor layer of the second conductivity type in said second opening using a molecular beam epitaxial selective growth method; and forming a third semiconductor layer of the first conductivity type on said first single-crystal semiconductor layer.

Claim 4

A method of manufacturing a semiconductor device, comprising the steps of: after a first insulating film is formed on a substrate of a first conductivity type, sequentially stacking a second insulating film having etching characteristics different from those of said first insulating film, a first semiconductor layer of a second conductivity type, and a third insulating film on said first insulating film; after a first opening reaching a surface of said first insulating film is formed, selectively side-etching only said second insulating film by isotropic etching to form a first undercut portion; after a second semiconductor layer of the second conductivity type is deposited on an entire surface of the resultant structure including said first opening, leaving said second semiconductor layer only in said first undercut portion; after a fourth insulating film having etching characteristics different from those of said first insulating film is formed, etching back said fourth insulating film by anisotropic etching to leave said fourth insulating film only on a side wall of said first opening; removing said first insulating film from said substrate by isotropic etching using said third and fourth insulating films as masks to expose a part of said substrate, so that a second opening and a second undercut portion in said first insulating film are formed; forming a first single-crystal semiconductor layer of the second conductivity type in said second opening using a molecular beam epitaxial selective growth method; and forming a third semiconductor layer of the first conductivity type on said first single-crystal semiconductor layer.

Claim 5

A method of manufacturing a semiconductor device, comprising the steps of: after a first insulating film is formed on a substrate of a first conductivity type, sequentially stacking a second insulating film having etching characteristics different from those of said first insulating film, a first semiconductor layer of a second conductivity type, and a third insulating film on said first insulating film; after a first opening reaching a surface of said first insulating film is formed, selectively side-etching only said second insulating film by isotropic etching to form a first undercut portion; after a second semiconductor layer of the second conductivity type is deposited on an entire surface of the resultant structure including said first opening, leaving said second semiconductor layer only in said first undercut portion; after a fourth insulating film having etching characteristics different from those of said first insulating film is formed, etching back said fourth insulating film by anisotropic etching to leave said fourth insulating film only on a side wall of said first opening; removing said first insulating film from said substrate by isotropic etching using said third and fourth insulating films as masks to expose a part of said substrate, so that a second opening and a second undercut portion in said first insulating film are formed; forming a first single-crystal semiconductor layer of the second conductivity type in said second opening using a molecular beam epitaxial selective growth method; and forming a third semiconductor layer of the first conductivity type on said first single-crystal semiconductor layer.