US4889819A
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US
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Method for fabricating shallow junctions by preamorphizing with dopant of same conductivity as substrate
Assignee: International Business Machines Corp
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Filing: 1988-05-20
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Granted: 1989-12-26
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Expires: 2008-05-20
Abstract
Abstract Shallow junctions of a first conductivity type in a semiconductor of the opposite conductivity type are fabricated by doping the substrate with a dopant of an opposite conductivity type than the first conductivity type to preamorphize portions of the substrate. The dopant of the opposite conductivity type must have a molecular weight that is higher than the molecular weight of the substrate. The substrate is then doped with the dopant of the first conductivity type to form the shallow junctions.
Inventors
- 👤 Bijan Davari
- 👤 Eti Ganin
- 👤 David L. Harame
- 👤 George A. Sai-Halasz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:47
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/21; H10P30/202; H10P30/204; H10P30/208; H10P30/28
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
136 words
A method for fabricating shallow junctions of a first conductivity type in a semiconductor, silicon substrate of a second and opposite conductivity type which comprises: doping said silicon substrate of a second and opposite conductivity type with a dopant of a second and opposite conductivity type than said first conductivity type and wherein said dopant of a second and opposite conductivity type has a molecular weight substantially higher than said substrate, and wherein said doping is to a depth at least sufficient for forming said shallow junctions to preamorphize portions of said substrate; and then doping said substrate with a dopant of said first conductivity type to form said shallow junctions wherein the dosage of the dopant of said first type is higher than the dosage of said dopant of a second and opposite conductivity type.
Claim 2
Independent Claim
136 words
A method for fabricating shallow junctions of a first conductivity type in a semiconductor, silicon substrate of a second and opposite conductivity type which comprises: doping said silicon substrate of a second and opposite conductivity type with a dopant of a second and opposite conductivity type than said first conductivity type and wherein said dopant of a second and opposite conductivity type has a molecular weight substantially higher than said substrate, and wherein said doping is to a depth at least sufficient for forming said shallow junctions to preamorphize portions of said substrate; and then doping said substrate with a dopant of said first conductivity type to form said shallow junctions wherein the dosage of the dopant of said first type is higher than the dosage of said dopant of a second and opposite conductivity type.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein the dosage of said dopant of a second and opposite type is about 10 13 to about 10 15 ions/cm 2 .
Claim 4
Dependent Claim
28 words
The method of claim 1 wherein the dosage of said dopant of a second and opposite type is about 5×10 13 to about 5×10 14 ions/cm 2 .
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein the dosage of said dopant of said first conductivity type is about 10 15 to about 2×10 16 ions/cm 2 .
Claim 6
Dependent Claim
27 words
The method of claim 3 wherein the dosage of said dopant of said first conductivity type is about 10 15 to about 2×10 16 ions/cm 2 .
Claim 7
Dependent Claim
19 words
The method of claim 1 wherein said shallow junctions are about 500 to 1000 angstroms below the substrate surface.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein said dopant of first conductivity type is boron.
Claim 9
Dependent Claim
25 words
The method of claim 7 wherein said dopant of a second and opposite conductivity type is selected from the group of antimony, bismuth, and arsenic.
Claim 10
Dependent Claim
17 words
The method of claim 7 wherein said dopant of a second and opposite conductivity type is antimony.
Claim 11
Dependent Claim
14 words
The method of claim 1 wherein said dopant of first conductivity type is phosphorus.
Claim 12
Dependent Claim
16 words
The method of claim 1 wherein said dopant of first conductivity type is phosphorus or arsenic.
Claim 13
Dependent Claim
19 words
The method of claim 10 wherein said dopant of a second and opposite conductivity type includes gallium or indium.
Claim 14
Dependent Claim
17 words
The method of claim 10 wherein said dopant of a second and opposite conductivity type is indium.
Claim 15
Dependent Claim
32 words
The method of claim 1 wherein the molecular weight of said dopant of a second and opposite conductivity type is at least about 1.5 times as heavy as that of the substrate.
Claim 16
Dependent Claim
20 words
The method of claim 1 wherein said shallow junctions are about 300 to about 1500 angstroms below the substrate surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |