US5811871A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor device comprising a bipolar transistor
Assignee: Renesas Electronics Corp
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Filing: 1997-01-23
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Granted: 1998-09-22
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Expires: 2017-01-23
Abstract
Abstract An bipolar transistor of BiCMOS is provided to improve the breakdown voltage between a collector and a base. A low concentration diffusion layer is provided at a main surface of a semiconductor substrate at a boundary between an outer perimeter of an external base layer and an end portion of a field oxide film. The low concentration diffusion layer expands from the main surface of the semiconductor substrate toward the inside of the substrate and has a concentration lower than the impurity concentration of the external base layer.
Inventors
- 👤 Takashi Nakashima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:17
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0112; H10D84/0119; H10D84/0107; H10D84/0109; H10D84/02; H10D84/03; H10D84/038; H10D84/40; H10D84/401; Y; Y10; Y10S; Y10S257/00; Y10S257/90
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
219 words
A semiconductor device comprising: a semiconductor substrate; a field oxide film provided at a main surface of said semiconductor substrate to separate an active region from another active region, an end portion of said field oxide film surrounding said active region; an emitter layer provided at a surface of said active region; a base layer provided at a surface of said active region and surrounding said emitter layer; an external base layer provided at a surface of said active region and surrounding a perimeter of said base layer, an inner perimeter of said external base layer being electrically connected to said base layer, an outer perimeter of said external base layer being in contact with said end portion of said field oxide film; and a low concentration impurity diffusion layer provided at a main surface of said semiconductor substrate along a boundary between said outer perimeter of said external base layer and a said end portion of said field oxide film and expanding from the main surface of said semiconductor substrate toward an inside of the substrate, said low concentration impurity diffusion layer having a concentration lower than that of an impurity of said external base layer, wherein said low concentration impurity diffusion layer wraps said external base layer except for the inner perimeter of said external base layer.
Claim 2
Dependent Claim
219 words
A semiconductor device comprising: a semiconductor substrate; a field oxide film provided at a main surface of said semiconductor substrate to separate an active region from another active region, an end portion of said field oxide film surrounding said active region; an emitter layer provided at a surface of said active region; a base layer provided at a surface of said active region and surrounding said emitter layer; an external base layer provided at a surface of said active region and surrounding a perimeter of said base layer, an inner perimeter of said external base layer being electrically connected to said base layer, an outer perimeter of said external base layer being in contact with said end portion of said field oxide film; and a low concentration impurity diffusion layer provided at a main surface of said semiconductor substrate along a boundary between said outer perimeter of said external base layer and a said end portion of said field oxide film and expanding from the main surface of said semiconductor substrate toward an inside of the substrate, said low concentration impurity diffusion layer having a concentration lower than that of an impurity of said external base layer, wherein said low concentration impurity diffusion layer wraps said external base layer except for the inner perimeter of said external base layer.
Claim 3
Dependent Claim
58 words
The semiconductor device according to claim 1, wherein a field effect transistor of LDD structure having a high concentration source/drain region and a low concentration source/drain region is provided at said another active region, and said low concentration impurity diffusion layer has a same conductivity type and substantially a same impurity concentration as said low concentration source/drain region.
Claim 4
Dependent Claim
37 words
The semiconductor device according to claim 2, wherein that end portion of said low concentration source/drain region which is closer to a channel shares a face with a sidewall of said gate electrode of said field-effect transistor.
Claim 5
Dependent Claim
30 words
The semiconductor device according to claim 2, wherein that end portion of said low concentration source/drain region which is closer to a channel is spaced apart from said gate electrode.
Claim 6
Dependent Claim
39 words
Semiconductor device according to claim 1, wherein a sidewall of said end portion of said field oxide film is provided with a sidewall spacer containing an impurity having a same conductivity type as a low concentration impurity diffusion layer.
Claim 7
Dependent Claim
46 words
The semiconductor device according to claim 1, comprising: an external base electrode provided on said semiconductor substrate, said external base electrode being in contact with and surrounding said external base layer; and a metal electrode provided on said external base electrode and surrounding said base layer.
Claim 8
Dependent Claim
43 words
The semiconductor device according to claim 1, wherein a channel cut layer is provided exactly under said field oxide film, and said low concentration impurity diffusion layer has a same conductivity type and substantially a same impurity concentration as said channel cut layer.
Claim 9
Dependent Claim
144 words
A semiconductor device comprising: a semiconductor substrate; a field oxide film provided at a main surface of said semiconductor substrate to separate an active region from another active region, an end portion of said field oxide film surrounding said active region; an emitter layer provided at a surface of said active region; a base layer provided at a surface of said active region and surrounding said emitter layer; and an external base electrode provided at a surface of said active region and surrounding a perimeter of said base layer, an inner perimeter of said external base electrode being electrically connected to said base layer, an outer perimeter of said external base electrode being in contact with said end portion of said field oxide film; wherein said end portion of said field oxide film is scraped at a surface thereof downward to provide a step.
Claim 10
Dependent Claim
144 words
A semiconductor device comprising: a semiconductor substrate; a field oxide film provided at a main surface of said semiconductor substrate to separate an active region from another active region, an end portion of said field oxide film surrounding said active region; an emitter layer provided at a surface of said active region; a base layer provided at a surface of said active region and surrounding said emitter layer; and an external base electrode provided at a surface of said active region and surrounding a perimeter of said base layer, an inner perimeter of said external base electrode being electrically connected to said base layer, an outer perimeter of said external base electrode being in contact with said end portion of said field oxide film; wherein said end portion of said field oxide film is scraped at a surface thereof downward to provide a step.
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