Method of manufacturing bipolar semiconductor device

Claim 1

A method of manufacturing a semiconductor device comprising the steps of: forming on a first conductivity type semiconductor substrate, a first insulating layer comprising a first oxidation resistant insulating film, a second insulating film formed on said first oxidation resistant insulating film and having a selectivity of an etching condition to said first insulating film, and a third oxidation resistant insulating film formed on said second insulating layer, forming a fourth oxidation resistant insulating film on the structure having said first insulating layer, selectively etching said fourth insulating film so that part of the fourth insulating film remains on the side wall of said first insulating layer, selectively oxidizing the surface of the semiconductor substrate using the remaining fourth insulating film as a mask to form an oxide layer on the semiconductor substrate, removing the remaining fourth and third insulating films, exposing the surface of said semiconductor region between said first insulating layer and said buried oxide layer, forming a first non-single crystal semiconductor film on the structure having said first insulating layer, selectively removing said first non-single crystal semiconductor film on said second insulating film, doping a second conductivity type impurity to said first non-single crystal semiconductor film, removing said second insulating film, thermally heating the surface of said first non-single crystal semiconductor film to form a thermal oxide film and to diffuse the impurity in said first non-single crystal semiconductor film into said semiconductor region to form a second conductivity type first semiconductor layer, removing said first insulating film, doping the second conductivity type impurity into the surface of said semiconductor region adjacent to the first semiconductor layer, using said thermal oxide film as a mask, to form a second semiconductor layer, and forming a first conductivity type third semiconductor layer on the surface of said second semiconductor layer.

Claim 2

A method of manufacturing a semiconductor device comprising the steps of: forming on a first conductivity type semiconductor substrate, a first insulating layer comprising a first oxidation resistant insulating film, a second insulating film formed on said first oxidation resistant insulating film and having a selectivity of an etching condition to said first insulating film, and a third oxidation resistant insulating film formed on said second insulating layer, forming a fourth oxidation resistant insulating film on the structure having said first insulating layer, selectively etching said fourth insulating film so that part of the fourth insulating film remains on the side wall of said first insulating layer, selectively oxidizing the surface of the semiconductor substrate using the remaining fourth insulating film as a mask to form an oxide layer on the semiconductor substrate, removing the remaining fourth and third insulating films, exposing the surface of said semiconductor region between said first insulating layer and said buried oxide layer, forming a first non-single crystal semiconductor film on the structure having said first insulating layer, selectively removing said first non-single crystal semiconductor film on said second insulating film, doping a second conductivity type impurity to said first non-single crystal semiconductor film, removing said second insulating film, thermally heating the surface of said first non-single crystal semiconductor film to form a thermal oxide film and to diffuse the impurity in said first non-single crystal semiconductor film into said semiconductor region to form a second conductivity type first semiconductor layer, removing said first insulating film, doping the second conductivity type impurity into the surface of said semiconductor region adjacent to the first semiconductor layer, using said thermal oxide film as a mask, to form a second semiconductor layer, and forming a first conductivity type third semiconductor layer on the surface of said second semiconductor layer.