Method for manufacturing a semiconductor device

Claim 1

A method for manufacturing a semiconductor integrated circuit device comprising the steps of: (a) forming a first insulating film on a semiconductor substrate having a buried diffusion region; (b) forming a poly crystalline semiconductor layer on a predetermined surface of the first insulating film and subsequently covering the same with a second insulating film; (c) forming an opening penetrating through the second insulating film, the poly crystalline semiconductor layer and the first insulating film to reach a surface of the semiconductor substrate; (d) forming a third insulating film on a side wall of the poly crystalline semiconductor layer exposed by forming the opening; (e) selectively forming a first step single crystalline semiconductor layer on the exposed semiconductor substrate; (f) removing, subsequent to step e), the third insulating film to expose the sidewall of the poly crystalline semiconductor layer; (g) selectively forming a second step single crystalline semiconductor layer on the first step single crystalline semiconductor layer so as to be connected to the poly crystalline semiconductory layer; and (h) forming an active base region and an emitter region in the second step single crystalline semiconductory layer.

Claim 2

A method for manufacturing a semiconductor integrated circuit device comprising the steps of: (a) forming a first insulating film on a semiconductor substrate having a buried diffusion region; (b) forming a poly crystalline semiconductor layer on a predetermined surface of the first insulating film and subsequently covering the same with a second insulating film; (c) forming an opening penetrating through the second insulating film, the poly crystalline semiconductor layer and the first insulating film to reach a surface of the semiconductor substrate; (d) forming a third insulating film on a side wall of the poly crystalline semiconductor layer exposed by forming the opening; (e) selectively forming a first step single crystalline semiconductor layer on the exposed semiconductor substrate; (f) removing, subsequent to step e), the third insulating film to expose the sidewall of the poly crystalline semiconductor layer; (g) selectively forming a second step single crystalline semiconductor layer on the first step single crystalline semiconductor layer so as to be connected to the poly crystalline semiconductory layer; and (h) forming an active base region and an emitter region in the second step single crystalline semiconductory layer.

Claim 3

A method for manufacturing a semiconductor integrated circuit device comprising the steps of: (a) forming a first insulating film on a semiconductor substrate having a buried diffusion region; (b) forming a poly crystalline semiconductor layer on a predetermined surface of the first insulating film and subsequently covering the same with a second insulating film; (c) forming an opening penetrating through the second insulating film, the poly crystalline semiconductor layer and the first insulating film to reach a surface of the semiconductor substrate; (d) forming a third insulating film on a sidewall of the poly crystalline semiconductor layer exposed by forming the opening; (e) selectively forming a first step single crystalline semiconductor layer on the exposed semiconductor substrate; (f) removing, subsequent to step e, the third insulating film to expose the sidewall of the poly crystalline semiconductor layer; (g) selectively forming a second step single crystalline semiconductor layer on the first step single crystalline semiconductor layer so as to be connected to the poly crystalline semiconductor layer; (h) forming a fourth insulating film by means of self-alignment on a sidewall of the second insulating film so as to cover a juncture of the exposed second step single crystalline semiconductor layer and the poly crystalline semiconductor layer; and (i) forming an opening within the first mentioned opening for diffusion to form an emitter region.

Claim 4

A method for manufacturing a semiconductor integrated circuit device comprising the steps of: (a) forming a first insulating film on a semiconductor substrate having a buried diffusion region; (b) forming a poly crystalline semiconductor layer on a predetermined surface of the first insulating film and subsequently covering the same with a second insulating film; (c) forming an opening penetrating through the second insulating film, the poly crystalline semiconductor layer and the first insulating film to reach a surface of the semiconductor substrate; (d) forming a third insulating film on a sidewall of the poly crystalline semiconductor layer exposed by forming the opening; (e) selectively forming a first step single crystalline semiconductor layer on the exposed semiconductor substrate; (f) removing, subsequent to step e, the third insulating film to expose the sidewall of the poly crystalline semiconductor layer; (g) selectively forming a second step single crystalline semiconductor layer on the first step single crystalline semiconductor layer so as to be connected to the poly crystalline semiconductor layer; (h) forming a fourth insulating film by means of self-alignment on a sidewall of the second insulating film so as to cover a juncture of the exposed second step single crystalline semiconductor layer and the poly crystalline semiconductor layer; and (i) forming an opening within the first mentioned opening for diffusion to form an emitter region.