Patent EP0439899A2 successfully refreshed from Google Patents.
EP0439899A2
Expired / Lapsed
EP
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Complementary bipolar transistors compatible with CMOS process
Assignee: Precision Monolithics Inc
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Filing: 1990-09-10
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Granted: —
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Expires: 2010-09-10
Abstract
Abstract A complementary bipolar process enables both PNP and NPN transistors to be added to a CMOS process with a minimum of extra fabrication steps. The P-well (80, 82) of a CMOS process is used for the collector region of the PNP transistor and the "down isolation" for the NPN transistor. A buried P diffusion (64, 66) provides "up" isolation for the NPN transistor and buried collector for the PNP transistor. A method for increasing the NPN buried collector to "up" isolation breakdown voltage is described which uses multiple N type impurities.
Inventors
- 👤 Mohammad S. Nasser
- 👤 Saurabh M. Desai
- 👤 Derek F. Bowers
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 21:53
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/40; H10D84/401; H10D10/00; H10D10/40; H10D10/421; H10D10/60; H10D84/01; H10D84/0107; H10D84/0109; H10D84/02; H10D84/03; H10D84/038; H10D84/60; H10D84/645; H10D84/67; H10W; H10W10/00; H10W10/01; H10W10/031; H10W10/30; H10W15/00; H10W15/01; Y; Y10; Y10S; Y10S148/00; Y10S148/009
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
156 words
A bipolar transistor structure, comprising: a semiconductor substrate (62) doped to a first conductivity; a tub isolation region (66) extending into the upper surface of said substrate (62) and doped to a second conductivity opposite to said first conductivity; a buried layer (68) extending into the upper surface of said tub isolation region (66) and having at least two types of dopants of said first conductivity, one of said dopants having a greater rate of thermal diffusion than the other; an epitaxial layer (70) grown over said substrate (62) said tub isolation region (66) and said buried layer (68) and doped to said first conductivity; a base region (94) set in said epitaxial layer (70) and doped to said second conductivity; and an emitter region (92) set in said base region (94) and doped to said first conductivity; and a collector region (96, 70) set in said epitaxial layer (70) and doped to said first conductivity.
Claim 2
Dependent Claim
35 words
The bipolar transistor structure of claim 1, further comprising: a vertical isolation region (82, 84) set in said epitaxial layer in electrical contact with said tub isolation region (66) and doped to said second conductivity.
Claim 3
Dependent Claim
65 words
The bipolar transistor structure of claim 1, wherein said at least two types of dopants are arsenic or antimony and phosphorous ions, with an initial concentration of arsenic or antimony dopant ions is on the order of about 10¹⁸ - 10¹⁹ ions per cubic centimeter, and an initial concentration of phosphorous dopant ions on the order of about 5x10¹⁵ - 5x10¹⁶ ions per cubic centimeter.
Claim 4
Dependent Claim
39 words
The bipolar transistor structure of claim 1, further comprising: a graded isolation region (86) located between said tub isolation region (66) and said buried layer (68), said graded isolation region (86) having a graded doping of said first conductivity.
Claim 5
Dependent Claim
180 words
A complementary bipolar transistor structure, comprising: an N-type semiconductor substrate (62); a PNP bipolar transistor structure, including: a first P tub isolation region (64) extending into the upper surface of said substrate; an N-type epitaxial layer (70) grown over said substrate (62) and said first P tub isolation region (64); a P-type collector region (80) set in the epitaxial layer (70); an N-type base region (90) set in the P-type collector region (80); and a P-type emitter region (88) set in the N-type base region (90); and an NPN bipolar transistor structure, including: a second P tub isolation region (66) extending into the upper surface of said substrate (62); an N-type buried layer (68) extending into the upper surface of said second P tub isolation region (66); an N-type epitaxial layer (70) grown over said substrate (62) and said second P-tube isolation region (66); a P-type base region (84) set in said epitaxial layer (70); and an N-type collector region (96, 70) set in said epitaxial layer (70); and an N-type emitter region (92) set in said base region (84).
Claim 6
Independent Claim
126 words
A method of forming complementary PNP and NPN bipolar transistors simultaneously with complementary P-channel and N-channel metal oxide semiconductor (CMOS) transistors on a common substrate (62) with an N-type epitaxial layer (70), comprising: forming a P-well for an N-channel MOS transistor and a collector well (80) for a PNP bipolar transistor layer by a common diffusion of P-type dopant into the epitaxial layer (70), forming a base (88) and emitter (90) within said collector well (80) for the PNP bipolar transistor, a base (94), emitter (92) and collector (96) within said epitaxial layer (70) for the NPN bipolar transistor, a source and drain within said P-well for the N-channel MOS transistor, and a source and drain within said epitaxial layer (70) for the P-channel MOS transistor.
Claim 7
Dependent Claim
41 words
The method of claim 6, wherein a P-type isolation barrier (82, 84) is formed in the epitaxial layer (70) around the NPN bipolar transistor in a diffusion of P-type dopant which is common with said P-well and collector well (80) diffusion.
Claim 8
Dependent Claim
33 words
The method of claim 6, wherein the source and drain of the P-channel MOS transistor and the emitter (88) of the PNP bipolar transistor are formed by a common diffusion of P-type dopant.
Claim 9
Dependent Claim
33 words
The method of claim 6, wherein the source and drain of the N-channel MOS transistor and the emitter (92) of the NPN bipolar transistor are formed by a common diffusion of N-type dopant.
Claim 10
Dependent Claim
50 words
The method of claim 9, wherein a guard ring for the N-channel MOS transistor and the base (94) of the NPN bipolar transistor are formed by a common diffusion of P-type dopant; and the emitter (92) of the NPN bipolar transistor is formed within the base (94) of that transistor.
References Cited (Backward Citations)
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