EP0281235A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Bipolar transistor fabrication utilizing CMOS techniques
Assignee: Texas Instruments Inc
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Filing: 1988-01-25
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Granted: —
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Expires: 2008-01-25
Abstract
Abstract Disclosed is a bipolar transistor and a method of fabrication thereof compatible with MOSFET devices. A transistor intrinsic base region (54) is formed in the face of a semiconductor well (22), and covered with a gate oxide (44). The gate oxide (44) is opened, and doped polysilicon is deposited thereover to form a polyemitter structure (68) in contact with the base region (54). Sidewall oxide (82, 84) is formed on the polyemitter structure (60). A collector region (90) and an extrinsic base region (100) are formed in the semiconductor well (22) and self aligned with respect to opposing side edges of the polyemitter sidewall oxide (82, 84).
Inventors
- 👤 David Spratt
- 👤 Rajiv R. Shah
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 12:59
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/40; H10D10/421; H10D10/01; H10D10/051; H10D84/00; H10D84/01; H10D84/0107; H10D84/0109; H10D84/02; H10D84/03; H10D84/038
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
161 words
A method of fabricating a bipolar transistor, comprising the steps of: forming a semiconductor well of a first conductivity type at the face of a semiconductor body; forming a semiconductor base region of a second conductivity type in said semiconductor well; forming a polycrystalline silicon emitter structure of said first conductivity type in contact with said semiconductor base region, said emitter structure having sidewalls; forming insulation on said sidewalls of said polycrystalline silicon emitter structure; forming a semiconductor collector region of a first conductivity type in said well and self aligned with respect to said insulation for said emitter structure; forming a semiconductor extrinsic base region of said second conductivity type in said well and self aligned with respect to said insulation for said emitter structure, said extrinsic base region contiguous with said semiconductor base region; and providing an impurity of said first conductivity type into said base region to thereby form a semiconductor emitter region of said first conductivity type.
Claim 2
Independent Claim
161 words
A method of fabricating a bipolar transistor, comprising the steps of: forming a semiconductor well of a first conductivity type at the face of a semiconductor body; forming a semiconductor base region of a second conductivity type in said semiconductor well; forming a polycrystalline silicon emitter structure of said first conductivity type in contact with said semiconductor base region, said emitter structure having sidewalls; forming insulation on said sidewalls of said polycrystalline silicon emitter structure; forming a semiconductor collector region of a first conductivity type in said well and self aligned with respect to said insulation for said emitter structure; forming a semiconductor extrinsic base region of said second conductivity type in said well and self aligned with respect to said insulation for said emitter structure, said extrinsic base region contiguous with said semiconductor base region; and providing an impurity of said first conductivity type into said base region to thereby form a semiconductor emitter region of said first conductivity type.
Claim 3
Dependent Claim
32 words
The method of Claim 1 further including forming a temporary blocking layer of material covering said emitter structure to prevent undesired impurities of an opposite conductivity type from entering said emitter structure.
Claim 4
Dependent Claim
41 words
The method of Claim 1 further including forming an insulation between said emitter structure and said semiconductor base region, and forming an opening in said insulation and forming said emitter structure through said opening in contact with said semiconductor base region.
Claim 5
Dependent Claim
48 words
The method of Claim 1 further including forming said base region and said collector region at the face of said semiconductor body, and forming a conductive silicide covering said base region, said collector region and a portion of said polycrystalline silicon emitter structure to provide electrical contact surfaces.
Claim 6
Dependent Claim
56 words
The method of Claim 4 further including forming a portion of said semiconductor well at the face of said semiconductor body adjacent said base region, and forming a metallic covering a portion of both said semiconductor well and said base to thereby form a barrier diode in parallel with a base-collector junction of said bipolar transistor.
Claim 7
Dependent Claim
28 words
The method of Claim 3 further including forming a MOSFET device gate insulator with said insulation, and forming a gate conductor with the material of said emitter structure.
Claim 8
Dependent Claim
36 words
The method of Claim 6 further including forming said gate insulator at the same time as said emitter insulation is formed, and forming said gate conductor and the same time as said emitter structure is formed.
Claim 9
Dependent Claim
35 words
The method of Claim 6 further including forming a sidewall insulation on said emitter structure at the same time and by the same steps as a corresponding sidewall insulation is formed on said gate conductor.
Claim 10
Dependent Claim
46 words
The method of Claim 6 further including forming a source and a drain region of first type of MOSFET device when said extrinsic base region is formed, and forming source and drain regions of a second type of MOSFET device when said collector region is formed.
Claim 11
Dependent Claim
115 words
A bipolar transistor, comprising: a semiconductor well of a first conductivity type; a conductive polycrystalline silicon strip overlying said well and extending substantially from one side thereof to the other, one said side of said polycrystalline silicon strip extending laterally beyond said semiconductor well; a semiconductor intrinsic base region of a second conductivity type underlying said polycrystalline silicon strip; a semiconductor emitter region in contact with said polycrystalline silicon emitter strip and formed in said intrinsic base region; and an extrinsic base region and a collector region formed on opposing sides of said polycrystalline silicon emitter strip, said extrinsic base region and said collector region being formed in electrical contact with said intrinsic base region.
Claim 12
Dependent Claim
115 words
A bipolar transistor, comprising: a semiconductor well of a first conductivity type; a conductive polycrystalline silicon strip overlying said well and extending substantially from one side thereof to the other, one said side of said polycrystalline silicon strip extending laterally beyond said semiconductor well; a semiconductor intrinsic base region of a second conductivity type underlying said polycrystalline silicon strip; a semiconductor emitter region in contact with said polycrystalline silicon emitter strip and formed in said intrinsic base region; and an extrinsic base region and a collector region formed on opposing sides of said polycrystalline silicon emitter strip, said extrinsic base region and said collector region being formed in electrical contact with said intrinsic base region.
Claim 13
Dependent Claim
38 words
The bipolar transistor of Claim 10 further including respective electrodes formed in contact with said extrinsic base region, with said collector region, and with a part of said polycrystalline silicon emitter strip extending laterally beyond said semiconductor well.
Claim 14
Dependent Claim
36 words
The bipolar transistor of Claim 10 further including a nested buried emitter comprising an emitter region formed in said base region and including a width shorter than the corresponding width of said polycrystalline silicon emitter strip.
Claim 15
Dependent Claim
41 words
The bipolar transistor of Claim 10 further including an insulation between said polycrystalline silicon emitter strip and said base region, and an opening in said insulation through which said polycrystalline silicon emitter strip is formed in contact with said base region.
Claim 16
Dependent Claim
40 words
The bipolar transistor of Claim 10 further including a walled emitter comprising said polycrystalline silicon emitter strip in contact with said base region, and said emitter includes a width substantially equal to the corresponding width of said polycrystalline emitter strip.
Claim 17
Dependent Claim
35 words
The bipolar transistor of Claim 10 further including sidewall insulation on said polycrystalline silicon emitter strip, and wherein said extrinsic base region and said collector regions are self aligned with respect to said sidewall insulation.
Claim 18
Dependent Claim
115 words
A lateral bipolar transistor having regions of alternate conductivity, comprising: an impurity well of a first conductivity type; a semiconductor base region of a second conductivity type formed in said impurity well of said first conductivity type; a semiconductor emitter region of said first conductivity type formed within said base region; a polycrystalline silicon conductor in electrical contact with said emitter region; silicon oxide formed on sidewalls of said polycrystalline silicon conductor; a semiconductor collector region of said first conductivity type formed in said impurity well and self aligned with said sidewall insulation; and an extrinsic base region of said second conductivity type formed in said impurity well and self aligned with said sidewall insulation.
Claim 19
Dependent Claim
115 words
A lateral bipolar transistor having regions of alternate conductivity, comprising: an impurity well of a first conductivity type; a semiconductor base region of a second conductivity type formed in said impurity well of said first conductivity type; a semiconductor emitter region of said first conductivity type formed within said base region; a polycrystalline silicon conductor in electrical contact with said emitter region; silicon oxide formed on sidewalls of said polycrystalline silicon conductor; a semiconductor collector region of said first conductivity type formed in said impurity well and self aligned with said sidewall insulation; and an extrinsic base region of said second conductivity type formed in said impurity well and self aligned with said sidewall insulation.
Claim 20
Dependent Claim
26 words
The lateral bipolar transistor of Claim 16 wherein said collector region and said intrinsic base region are formed on opposing sides of said polycrystalline silicon conductor.
Claim 21
Dependent Claim
47 words
The lateral bipolar transistor of Claim 16 further including a buried contact formed where said emitter region is in electrical contact with said polycrystalline silicon conductor, and further including a contact laterally offset from said buried contact for effecting external electrical contact to said polycrystalline silicon conductor.
Claim 22
Dependent Claim
31 words
The lateral bipolar transistor of Claim 18 wherein said buried contact is of width smaller than the corresponding width of that part of said polycrystalline silicon conductor overlying said buried contact.
Claim 23
Dependent Claim
34 words
The lateral bipolar transistor of Claim 18 wherein said polycrystalline silicon conductor is elongate and extends beyond said impurity well, and said offset contact is disposed proximate an end of said polycrystalline silicon conductor.
Claim 24
Independent Claim
89 words
A method of forming self-aligned semiconductor regions in a bipolar transistor, comprising: forming a semiconductor base region in the face of a substrate; forming a doped polycrystalline silicon layer in contact with said base region at a location to define an emitter region; forming said polycrystalline silicon with an edge extending laterally beyond said emitter region; forming a collector region in the face of said substrate aligned with said polycrystalline silicon edge; and diffusing the dopant of said polycrystalline silicon into said base region to form said emitter region.
Claim 25
Independent Claim
89 words
A method of forming self-aligned semiconductor regions in a bipolar transistor, comprising: forming a semiconductor base region in the face of a substrate; forming a doped polycrystalline silicon layer in contact with said base region at a location to define an emitter region; forming said polycrystalline silicon with an edge extending laterally beyond said emitter region; forming a collector region in the face of said substrate aligned with said polycrystalline silicon edge; and diffusing the dopant of said polycrystalline silicon into said base region to form said emitter region.
Claim 26
Dependent Claim
25 words
The method of Claim 21 further including forming an insulator on said edge of said polycrystalline silicon and forming said collector aligned with said insulator.
Claim 27
Dependent Claim
21 words
The method of Claim 22 further including forming a portion of said insulator underlying a peripheral edge of said polycrystalline silicon.
Claim 28
Dependent Claim
37 words
The method of Claim 23 further including forming said insulator underlying said polycrystalline silicon so as to define an opening in said insulator, and forming said polycrystalline silicon in said opening in contact with said base region.
Claim 29
Dependent Claim
45 words
The method of Claim 21 wherein said polycrystalline silicon edge defines a first edge, and further including forming a second edge on said polycrystalline silicon and forming an extrinsic base region in said substrate aligned with said second edge and contiguous with said base region.
References Cited (Backward Citations)
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