Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
179 words
A method of manufacturing a semiconductor device, characterized by comprising the steps of: forming a first oxide film (3) on a semiconductor substrate by thermal oxidation; forming a nitride film (4) on said first oxide film (3); removing each portion of said first oxide film (3) and said nitride film (4) by etching to expose a first portion (5) selected from said substrate; forming a first polysilicon film (6) of a first conductivity type on said first exposed portion (5) of said substrate; forming a second oxide film (7) thicker than said first oxide film (3) on a portion selected from said nitride film (4) and on said first polysilicon film (6) to surround said first polysilicon film (6); removing a portion of said nitride film (4) which is not covered with said second oxide film (7) and a portion of said first oxide film (3) therebelow by etching to expose a second portion (9) of said substrate; and forming a second polysilicon film (10) of a second conductivity type on said second exposed portion (9) of said substrate.
Claim 2
Dependent Claim
51 words
A method according to claim 1, characterized in that said method includes the step of forming a region (2) of a first conductivity type on said semiconductor substrate prior to said step of forming said first oxide film (3), and said first oxide film (3) is formed on said region (2).
Claim 3
Dependent Claim
19 words
A method according to claim 1, characterized in that said steps of etching are performed by reactive ion etching.
Claim 4
Dependent Claim
24 words
A method according to claim 1, characterized in that said step of forming said nitride film (4) is performed by low-pressure chemical vapor deposition.
Claim 5
Dependent Claim
36 words
A method according to claim 1, characterized in that said substrate is a silicon substrate, and said oxide film and said nitride film are respectively a silicon oxide film (3) and a silicon nitride film (4).
Claim 6
Independent Claim
233 words
A method of manufacturing a bipolar transistor, characterized by comprising the steps of: forming a first oxide film (3) on a semiconductor substrate by thermal oxidation; forming a nitride film (4) on said first oxide film (3); removing each portion of said first oxide film (3) and said nitride film (4) by etching to expose a first portion selected from said substrate so as to form a base contact hole (5); forming a first polysilicon film including an impurity of a first conductivity type and serving as a base electrode (6) on said base contact hole (5); forming a second oxide film (7) having a thickness larger than that of said first oxide film (3) by thermal oxidation around said base contact hole (5) to surround said first polysilicon film (6); removing a portion of said nitride film (4) which is not covered with said second oxide film (7) and a portion of said first oxide film (3) therebelow by etching to expose a second portion of said substrate so as to form an emitter contact hole (9); forming a second polysilicon film containing an impurity of a second conductivity type and serving as an emitter electrode (10) in said emitter contact hole (9); and diffusing said impurity of the second conductivity type contained in said second polysilicon film (10) by annealing to form an emitter region (11) of the second conductivity type.
Claim 7
Dependent Claim
55 words
A method according to claim 6, characterized in that said method includes the steps of forming a layer (1) of the second conductivity type on said semiconductor substrate and forming a base region (2) of the first conductivity type on said layer, and said first oxide film (3) is formed on said base region (2).
Claim 8
Dependent Claim
19 words
A method according to claim 6, characterized in that said steps of etching are performed by reactive ion etching.
Claim 9
Dependent Claim
24 words
A method according to claim 6, characterized in that said step of forming said nitride film (4) is performed by low-pressure chemical vapor deposition.
Claim 10
Dependent Claim
36 words
A method according to claim 6, characterized in that said substrate is a silicon substrate, and said oxide film and said nitride film are respectively a silicon oxide film (3) and a silicon nitride film (4).