Method for producing a semiconductor device utilizing V-groove etching and thermal oxidation

Claim 1

A method for producing a semiconductor device which comprises at least one bipolar transistor and a VIP isolating layer which are formed in both an epitaxial layer and a semiconductor substrate, with an emitter region of said bipolar transistor coming into contact with said VIP isolating layer, comprising the steps of: forming a buried layer in said semiconductor substrate having a first conductivity type, the buried layer having the opposite conductivity type; forming said epitaxial layer having said opposite conductivity type on said semiconductor substrate; forming a first insulating layer on said epitaxial layer; forming an oxidation masking layer on said first insulating layer; selectively etching said oxidation masking layer and said first insulating layer to form an opening; anisotrophically etching said epitaxial layer and said semiconductor substrate through said opening to form a V-groove, the bottom peak of which enters said semiconductor substrate through said buried layer; introducing impurities having said first conductivity type into exposed portions of said epitaxial layer and said semiconductor substrate in said V-groove; selectively oxidizing said exposed portions in said V-groove to form a second insulating layer; forming a polycrystalline silicon layer on said second insulating layer to fill said V-groove; selectively oxidizing said polycrystalline silicon layer to form a relatively thick insulating layer of silicon dioxide including a bird's beak; removing said oxidation masking layer; forming a base region through a portion of said first insulating layer to have said first conductivity type in said epitaxial layer and in contact with said impurity-introduced region; forming an emitter region having said opposite conductivity type in said base region and in contact with said relatively thick insulating layer; forming an impurity-introduced region for electrical contact, having said opposite conductivity type, in said epitaxial layer outside of said base and emitter regions; and forming electrodes on portions of said base emitter and impurity-introduced regions for electrical contact.

Claim 2

A method for producing a semiconductor device which comprises at least one bipolar transistor and a VIP isolating layer which are formed in both an epitaxial layer and a semiconductor substrate, with an emitter region of said bipolar transistor coming into contact with said VIP isolating layer, comprising the steps of: forming a buried layer in said semiconductor substrate having a first conductivity type, the buried layer having the opposite conductivity type; forming said epitaxial layer having said opposite conductivity type on said semiconductor substrate; forming a first insulating layer on said epitaxial layer; forming an oxidation masking layer on said first insulating layer; selectively etching said oxidation masking layer and said first insulating layer to form an opening; anisotrophically etching said epitaxial layer and said semiconductor substrate through said opening to form a V-groove, the bottom peak of which enters said semiconductor substrate through said buried layer; introducing impurities having said first conductivity type into exposed portions of said epitaxial layer and said semiconductor substrate in said V-groove; selectively oxidizing said exposed portions in said V-groove to form a second insulating layer; forming a polycrystalline silicon layer on said second insulating layer to fill said V-groove; selectively oxidizing said polycrystalline silicon layer to form a relatively thick insulating layer of silicon dioxide including a bird's beak; removing said oxidation masking layer; forming a base region through a portion of said first insulating layer to have said first conductivity type in said epitaxial layer and in contact with said impurity-introduced region; forming an emitter region having said opposite conductivity type in said base region and in contact with said relatively thick insulating layer; forming an impurity-introduced region for electrical contact, having said opposite conductivity type, in said epitaxial layer outside of said base and emitter regions; and forming electrodes on portions of said base emitter and impurity-introduced regions for electrical contact.