US6040249A
Expired / Lapsed
US
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Method of improving diffusion barrier properties of gate oxides by applying ions or free radicals of nitrogen in low energy
Assignee: Texas Instruments Inc
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Filing: 1997-08-08
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Granted: 2000-03-21
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Expires: 2017-08-08
Abstract
Abstract A method of providing a MOSFET having improved gate oxide diffusion barrier properties, which comprises providing a partially fabricated MOSFET having an exposed gate oxide surface. During MOSFET fabrication, the surface of the exposed gate oxide is converted to an oxynitride by applying one or both of ions or free radicals of nitrogen to the exposed gate oxide surface. Fabrication of the MOSFET is then completed in standard manner.
Inventors
- 👤 Thomas C. Holloway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:56
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/01344; H10D64/01348; H10D64/60; H10D64/66; H10D64/68; H10D64/693
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
75 words
A method of providing a MOSFET having improved gate oxide diffusion barrier properties, comprising the steps of: (a) providing a partially fabricated MOSFET having an exposed gate oxide surface; (b) converting the surface of said exposed gate oxide to an oxynitride by a very low energy implant of nitrogen into said exposed gate oxide surface wherein said low energy is from about 50 eV to about 1000 eV; and (c) completing fabrication of said MOSFET.
Claim 2
Independent Claim
75 words
A method of providing a MOSFET having improved gate oxide diffusion barrier properties, comprising the steps of: (a) providing a partially fabricated MOSFET having an exposed gate oxide surface; (b) converting the surface of said exposed gate oxide to an oxynitride by a very low energy implant of nitrogen into said exposed gate oxide surface wherein said low energy is from about 50 eV to about 1000 eV; and (c) completing fabrication of said MOSFET.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein said low energy implant is an implant provided by the techniques of reactive ion etching.
Claim 4
Independent Claim
95 words
A method of fabricating a gate oxide for a MOSFET having a diffusion barrier thereon, comprising the steps of: (a) providing a partially fabricated MOSFET semiconductor device having a layer of semiconductor material and an exposed gate oxide on said layer of semiconductor material forming an interface with said semiconductor layer; and (b) subjecting said exposed surface to at least one of free radicals or ions of nitrogen to form an oxynitride region at the exposed surface of said gate oxide by low energy ion implantation of from about 50 eV to about 1000 eV.
Claim 5
Independent Claim
95 words
A method of fabricating a gate oxide for a MOSFET having a diffusion barrier thereon, comprising the steps of: (a) providing a partially fabricated MOSFET semiconductor device having a layer of semiconductor material and an exposed gate oxide on said layer of semiconductor material forming an interface with said semiconductor layer; and (b) subjecting said exposed surface to at least one of free radicals or ions of nitrogen to form an oxynitride region at the exposed surface of said gate oxide by low energy ion implantation of from about 50 eV to about 1000 eV.
Claim 6
Dependent Claim
19 words
The method of claim 3 wherein said oxynitride is spaced from said interface by at least one atomic monolayer.
Claim 7
Dependent Claim
63 words
The method of claim 3 wherein said exposed surface is subjected to free radicals by the step of heating said partially fabricated MOSFET semiconductor device to a temperature in the range of from about 27° C. to about 800° C. and the steps of generating and applying said free radicals to said exposed gate oxide by providing nitrogen gas in a microwave plasma.
Claim 8
Dependent Claim
12 words
The method of claim 5 wherein said temperature is about 650° C.
Claim 9
Dependent Claim
36 words
The method of claim 3 wherein the depth of said oxynitride region is from about one atomic monolayer to about 90 percent of the distance from the exposed surface of the oxynitride layer to said interface.
Claim 10
Dependent Claim
36 words
The method of claim 5 wherein the depth of said oxynitride region is from about one atomic monolayer to about 90 percent of the distance from the exposed surface of the oxynitride layer to said interface.
Claim 11
Dependent Claim
36 words
The method of claim 6 wherein the depth of said oxynitride region is from about one atomic monolayer to about 90 percent of the distance from the exposed surface of the oxynitride layer to said interface.
Claim 12
Dependent Claim
64 words
The method of claim 3 wherein said exposed surface is subjected to ions by the steps of heating said partially fabricated MOSFET semiconductor device to a temperature of about 400° C., providing a parallel plate reactor with RF power capacitively coupled to said heated partially fabricated MOSFET semiconductor device in the presence of N 2 gas and causing said reactor to provide said ions.
Claim 13
Dependent Claim
39 words
The method of claim 10 wherein the pressure of said N 2 gas and RF power are set to obtain about a -300 volt DC bias at said device to provide nitrogen ion bombardment of the exposed oxide layer.
Claim 14
Dependent Claim
33 words
The method of claim 3 wherein said exposed surface is subjected to both of free radicals or ions of nitrogen to form an oxynitride region at the exposed surface of said gate oxide.
Claim 15
Dependent Claim
119 words
The method of claim 12 wherein said exposed surface is subjected to ions by the steps of heating said partially fabricated MOSFET semiconductor device to a temperature of about 400° C., providing a parallel plate reactor with RF power capacitively coupled to said heated partially fabricated MOSFET semiconductor device in the presence of N 2 gas and causing said reactor to provide said ions and said exposed surface is subjected to free radicals by the step of heating said partially fabricated MOSFET semiconductor device to a temperature in the range of from about 27° C. to about 800° C. and generating and applying to said exposed gate oxide said free radicals by providing nitrogen gas in a microwave plasma.
Claim 16
Dependent Claim
19 words
The method of claim 3 wherein said oxynitride is formed by applying free radicals of nitrogen to said 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) | 2003-03-21 | 2003-09-20 | 2004-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-03-21 | 2007-09-20 | 2008-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-03-21 | 2011-09-20 | 2012-03-21 | $7700.00 | Window Closed / Lapsed |