US4683645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of fabricating MOS devices having shallow source and drain junctions
Assignee: STMicroelectronics NV
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Filing: 1985-12-24
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Granted: 1987-08-04
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Expires: 2005-12-24
Abstract
Abstract In a metal oxide semiconductor field effect transistor fabrication process, refractory metal is deposited over designated source and drain areas within a silicon substrate. Refractory metal and silicon at the interface is then mixed by ion implantation of a heavy neutral ion species such as germanium. To minimize source/drain junction depth, the source and drain locations can be subjected to bombardment by a lighter ion such as silicon which amorphizes silicon to a predetermined depth under the designated source and drain regions and so substantially confines dopant diffusion to the silicon amorphized region. To render the source and drain of desired conductivity type, an ion implantation of a non-neutral ion is then performed.
Inventors
- 👤 Hussein M. Naguib
- 👤 Iain D. Calder
- 👤 Vu Q. Ho
- 👤 Abdalla A. Naem
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:10
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/202; H10P30/204; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10P30/208; H10P30/21; H10P30/212; H10P30/28; Y; Y10; Y10S; Y10S148/00; Y10S148/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
136 words
A process for the fabrication of an MOS semiconductor device comprising: forming on a silicon substrate regions of field oxide; forming at a region not occupied by field oxide a gate oxide layer; forming a device gate over a region of said gate oxide layer; designating source and drain areas and removing gate oxide at said source and drain areas; depositing a refractory metal on the silicon substrate at said source and drain regions; implanting germanium ions at the source and drain areas to mix silicon and the refractory metal at an interface therebetween; implanting silicon ions at the source and drain areas to cause amorphization of the silicon to a predetermined depth; and implanting dopant ions of a predetermined conductivity type at the source and drain areas whereby to render said areas of said type.
Claim 2
Dependent Claim
136 words
A process for the fabrication of an MOS semiconductor device comprising: forming on a silicon substrate regions of field oxide; forming at a region not occupied by field oxide a gate oxide layer; forming a device gate over a region of said gate oxide layer; designating source and drain areas and removing gate oxide at said source and drain areas; depositing a refractory metal on the silicon substrate at said source and drain regions; implanting germanium ions at the source and drain areas to mix silicon and the refractory metal at an interface therebetween; implanting silicon ions at the source and drain areas to cause amorphization of the silicon to a predetermined depth; and implanting dopant ions of a predetermined conductivity type at the source and drain areas whereby to render said areas of said type.
Claim 3
Dependent Claim
21 words
A process as defined in claim 1 wherein the dopant is boron whereby the source and drain areas are rendered p-type.
Claim 4
Dependent Claim
21 words
A process as defined in claim 1 wherein the dopant is arsenic whereby the source and drain areas are rendered n-type.
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) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |