Patent US5150184A successfully refreshed from Google Patents.
US5150184A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming emitters in a BiCMOS process
Assignee: Texas Instruments Inc
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Filing: 1991-05-24
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Granted: 1992-09-22
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Expires: 2011-05-24
Abstract
Abstract A bipolar transistor and method of making the same is disclosed. The transistor has an emitter region which is diffused from polysilicon into the intrinsic base region, where the polysilicon is doped with two dopant species of different diffusivity. The impurity concentration of the higher diffusivity species, for example phosphorous, can be selected to define the emitter junction depth, which is preferably shallow, while the impurity concentration of the lower diffusivity species, for example arsenic, can be selected to provide a high conductivity emitter electrode, as well as reduce the sensitivity of the emitter electrode to counterdoping from the implantation of the extrinsic base region. The structure is compatible with BiCMOS processing, as the same anneal can be used to diffuse the emitter and the source/drains of the MOS transistors, with the emitter junction depth optimized via the implant conditions of the higher diffusivity species. The emitter electrode according to the invention can also be exposed to the opposite conductivity type source/drain implant, with reduced sensitivity to counterdoping.
Inventors
- 👤 Robert H. Eklund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:38
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/61; H10D; H10D84/00; H10D84/01; H10D84/0107; H10D84/0109; H10D84/02; H10D84/03; H10D84/038; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/1414; H10P32/17; H10P32/171
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
130 words
A bipolar transistor formed at a surface of a semiconductor body, comprising: a collector region of a first conductivity type; a base region of a second conductivity type disposed within said collector region at said surface; an emitter electrode comprising a semiconductor material slightly doped with a remaining portion of a first dopant species and heavily doped with a second dopant species, both of said first conductivity type, said first dopant species having a relatively greater diffusivity than said second dopant species; and an emitter region of said first conductivity type disposed within said base region and in contact with said emitter electrode, said emitter region heavily doped with said first dopant and slightly doped with said second dopant by said first and second dopants diffused from said emitter electrode.
Claim 2
Dependent Claim
130 words
A bipolar transistor formed at a surface of a semiconductor body, comprising: a collector region of a first conductivity type; a base region of a second conductivity type disposed within said collector region at said surface; an emitter electrode comprising a semiconductor material slightly doped with a remaining portion of a first dopant species and heavily doped with a second dopant species, both of said first conductivity type, said first dopant species having a relatively greater diffusivity than said second dopant species; and an emitter region of said first conductivity type disposed within said base region and in contact with said emitter electrode, said emitter region heavily doped with said first dopant and slightly doped with said second dopant by said first and second dopants diffused from said emitter electrode.
Claim 3
Dependent Claim
40 words
The bipolar transistor of claim 1, further comprising: a dielectric layer disposed over said base region, wherein said emitter electrode overlies said dielectric layer and is in contact with said base region through a contact etched through said dielectric layer.
Claim 4
Dependent Claim
26 words
The bipolar transistor of claim 2, wherein the shape of said emitter region is characteristic of diffusion of dopant from said emitter electrode through said contact.
Claim 5
Dependent Claim
38 words
The bipolar transistor of claim 1, further comprising: an extrinsic base region of said second conductivity type formed within said base region at said surface, said extrinsic base region being relatively more heavily doped than said base region.
Claim 6
Dependent Claim
20 words
The bipolar transistor of claim 1, wherein said first conductivity type is n-type and said second conductivity type is p-type.
Claim 7
Dependent Claim
12 words
The bipolar transistor of claim 5, wherein said first dopant is phosphorous.
Claim 8
Dependent Claim
12 words
The bipolar transistor of claim 6, wherein said second dopant is arsenic.
Claim 9
Dependent Claim
17 words
The device of claim 1 wherein said emitter electrode is formed of two layers of semiconductor material.
Claim 10
Dependent Claim
153 words
A bipolar transistor formed at a surface of a semiconductor body, comprising: a collector having a first conductivity formed in said body; a region disposed within said collector at said surface, said region including a dopant of a second conductivity type and defining a base portion having a second conductivity and an emitter portion disposed within said base portion; and a semiconductor emitter electrode in contact with said region at said surface, said semiconductor emitter electrode slightly doped with a remaining portion of a first dopant and heavily doped with a second dopant, both of said first conductivity type, said first dopant having a relatively high diffusivity relative to said second dopant, said emitter portion heavily doped with said first dopant and slightly doped with said second dopant, both said first and second dopants in said emitter portion diffused from said emitter electrode such that said emitter portion is of said first conductivity.
Claim 11
Dependent Claim
153 words
A bipolar transistor formed at a surface of a semiconductor body, comprising: a collector having a first conductivity formed in said body; a region disposed within said collector at said surface, said region including a dopant of a second conductivity type and defining a base portion having a second conductivity and an emitter portion disposed within said base portion; and a semiconductor emitter electrode in contact with said region at said surface, said semiconductor emitter electrode slightly doped with a remaining portion of a first dopant and heavily doped with a second dopant, both of said first conductivity type, said first dopant having a relatively high diffusivity relative to said second dopant, said emitter portion heavily doped with said first dopant and slightly doped with said second dopant, both said first and second dopants in said emitter portion diffused from said emitter electrode such that said emitter portion is of said first conductivity.
Claim 12
Dependent Claim
42 words
The bipolar transistor of claim 9, further comprising: a dielectric layer formed over said region prior to said step of forming a semiconductor emitter electrode, said dielectric layer defining a via therethrough such that said semiconductor emitter electrode contacts said base region.
Claim 13
Dependent Claim
12 words
The bipolar transistor of claim 9, wherein said first dopant is phosphorous.
Claim 14
Dependent Claim
12 words
The bipolar transistor of claim 11, wherein said second dopant is arsenic.
Claim 15
Dependent Claim
13 words
The bipolar transistor of claim 9, wherein said semiconductor layer is polycrystalline silicon.
Claim 16
Dependent Claim
20 words
The bipolar transistor of claim 9, wherein said first and second dopants are ion implanted into said semiconductor emitter electrode.
Claim 17
Dependent Claim
17 words
The device of claim 9 wherein said emitter electrode is formed of two layers of semiconductor material.
Claim 18
Dependent Claim
214 words
A bipolar and field effect transistor formed at a surface of a semiconductor body, comprising: a collector having a first conductivity formed in said body; a region disposed within said collector at a first location of said surface, said region including a dopant of a second conductivity type and defining a base portion having a second conductivity and an emitter portion disposed within said base portion; a first well of said first conductivity type defined in said body at a second location of said surface; a semiconductor emitter electrode in contact with said region, said emitter electrode slightly doped with a remaining portion of a first dopant and heavily doped with a second dopant, both of said first conductivity type, said first dopant having a relatively high diffusivity relative to said second dopant, said emitter portion heavily doped with said first dopant and slightly doped with said second dopant, both said first and second dopants in said emitter portion diffused from said emitter electrode such that said emitter portion is of said first conductivity; a first semiconductor gate electrode overlying said first well, said first gate electrode doped with at least one of said first and second dopants, portions of said first well near said gate electrode including dopants of said second conductivity type.
Claim 19
Dependent Claim
214 words
A bipolar and field effect transistor formed at a surface of a semiconductor body, comprising: a collector having a first conductivity formed in said body; a region disposed within said collector at a first location of said surface, said region including a dopant of a second conductivity type and defining a base portion having a second conductivity and an emitter portion disposed within said base portion; a first well of said first conductivity type defined in said body at a second location of said surface; a semiconductor emitter electrode in contact with said region, said emitter electrode slightly doped with a remaining portion of a first dopant and heavily doped with a second dopant, both of said first conductivity type, said first dopant having a relatively high diffusivity relative to said second dopant, said emitter portion heavily doped with said first dopant and slightly doped with said second dopant, both said first and second dopants in said emitter portion diffused from said emitter electrode such that said emitter portion is of said first conductivity; a first semiconductor gate electrode overlying said first well, said first gate electrode doped with at least one of said first and second dopants, portions of said first well near said gate electrode including dopants of said second conductivity type.
Claim 20
Dependent Claim
21 words
The transistors of claim 16, wherein said first conductivity type is n type, and said second conductivity type is p type.
Claim 21
Dependent Claim
11 words
The transistors of claim 16, wherein said first dopant is phosphorous.
Claim 22
Dependent Claim
11 words
The transistors of claim 18, wherein said second dopant is arsenic.
Claim 23
Dependent Claim
13 words
The transistors of claim 16, wherein said semiconductor emitter electrode is polycrystalline silicon.
Claim 24
Dependent Claim
21 words
The device of claim 16 wherein said emitter electrode and said gate electrode are formed of two layers of semiconductor material.
Claim 25
Dependent Claim
52 words
The device of claim 16 and further comprising: a second well of said second conductivity type defined in said body at a third location of said surface; and a second semiconductor gate electrode overlying said second well, said second gate electrode doped with at least one of said first and second dopants.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-22 | 1996-03-23 | 1996-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-22 | 2000-03-23 | 2000-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-22 | 2004-03-23 | 2004-09-22 | $7700.00 | Window Closed / Lapsed |