US5908312A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor device fabrication
Assignee: Nokia of America Corp
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Filing: 1997-05-28
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Granted: 1999-06-01
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Expires: 2017-05-28
Abstract
Abstract A method of preventing diffusion penetration of the dopant used to dope polysilicon gate material in a MOSFET is disclosed. Atomic nitrogen is introduced into the substrate prior to gate oxide growth. The nitrogen later diffuses upward into the gate oxide and blocks subsequent ion implanted gate dopants from penetrating to the substrate. Low dosages of atomic nitrogen implantation, while not significantly affecting gate oxide growth rate, produce significant improvements in the damage immunity of thin gate oxides.
Inventors
- 👤 Kin Ping Cheung
- 👤 Steven James Hillenius
- 👤 Chun-Ting Liu
- 👤 Yi Ma
- 👤 Pradip Kumar Roy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:18
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/0134; H10D64/01344; H10D64/01348; H10D64/60; H10D64/66; H10D64/68; H10D64/693; H10P; H10P30/00; H10P30/20; H10P30/202; H10P30/204; H10P30/208; H10P30/225
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
62 words
A method of semiconductor integrated circuit fabrication comprising: embedding atomic nitrogen into a substrate such that said atomic nitrogen extends to a top surface of said substrate; forming a dielectric layer upon said substrate after said embedding step; forming a material layer upon said dielectric layer; exposing said material layer to a dopant species; patterning said material layer to form a gate.
Claim 2
Independent Claim
62 words
A method of semiconductor integrated circuit fabrication comprising: embedding atomic nitrogen into a substrate such that said atomic nitrogen extends to a top surface of said substrate; forming a dielectric layer upon said substrate after said embedding step; forming a material layer upon said dielectric layer; exposing said material layer to a dopant species; patterning said material layer to form a gate.
Claim 3
Dependent Claim
13 words
The method of claim 1 in which said embedding step includes ion implantation.
Claim 4
Dependent Claim
40 words
The method of claim 2 in which said embedding step includes ion implantation which is performed at an energy between 5 KeV and 50 KeV and at a dose between 10 13 /cm 2 and 5×10 14 /cm 2 .
Claim 5
Dependent Claim
12 words
The method of claim 1 in which said material layer is polysilicon.
Claim 6
Dependent Claim
12 words
The method of claim 1 in which said dopant species is boron.
Claim 7
Dependent Claim
14 words
The method of claim 1 in which said dielectric is thermally grown silicon dioxide.
Claim 8
Dependent Claim
26 words
The method of claim 6 in which said dielectric is formed by exposing said substrate to oxygen at a temperature between 700° C. and 1000° C.
Claim 9
Dependent Claim
19 words
The method of claim 1 in which the thickness of said dielectric is between 10 Å and 200 Å.
Claim 10
Dependent Claim
18 words
The method of claim 1 in which the thickness of said material layer is between 500Å and 3000Å.
Claim 11
Dependent Claim
22 words
The method of claim 1 in which said dielectric is formed by exposing said substrate to an atmosphere of N 2 O.
Claim 12
Dependent Claim
18 words
The method of claim 10 in which said exposure occurs at a temperature between 800 and 900° C.
Claim 13
Dependent Claim
22 words
The method of claim 3 in which the dose is about 1×10 14 /cm 2 to about 5×10 14 /cm 2 .
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) | 2002-05-31 | 2002-11-30 | 2003-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-31 | 2006-11-30 | 2007-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-31 | 2010-11-30 | 2011-06-01 | $7700.00 | Window Closed / Lapsed |