US4612258A
Expired / Lapsed
US
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Method for thermally oxidizing polycide substrates in a dry oxygen environment and semiconductor circuit structures produced thereby
Assignee: Zilog Inc
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Filing: 1984-12-21
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Granted: 1986-09-16
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Expires: 2004-12-21
Abstract
Abstract A method of thermally oxidizing polycide substrates in a dry oxygen environment as well as a MOSFET structure provided by the method are disclosed. The method includes heating a plurality of polycide substrates to temperatures greater than about 800 degrees Centigrade in a dry oxygen environment, and introducing into the environment an amount of a halogenated alkane gas sufficient to induce oxidation.
Inventors
- 👤 Juine-Kai Tsang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:18
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12528; Y10T428/12986; Y10T428/26; Y10T428/261
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
92 words
A method of thermally oxidizing a polycide substrate in a dry oxygen environment, comprising the steps of: emplacing a polycide substrate in a substantially enclosed chamber, said polycide substrate having a metallic silicide layer and an underlying layer of polycrystalline silicon; filling said chamber with oxygen gas; heating said substrate to a temperature of at least 800 degrees Centigrade for a predetermined length of time; and introducing into said chamber an amount of a halogenated hydrocarbon gas sufficient to induce oxidation of said substrate, whereby a silicon dioxide layer is provided thereon.
Claim 2
Independent Claim
92 words
A method of thermally oxidizing a polycide substrate in a dry oxygen environment, comprising the steps of: emplacing a polycide substrate in a substantially enclosed chamber, said polycide substrate having a metallic silicide layer and an underlying layer of polycrystalline silicon; filling said chamber with oxygen gas; heating said substrate to a temperature of at least 800 degrees Centigrade for a predetermined length of time; and introducing into said chamber an amount of a halogenated hydrocarbon gas sufficient to induce oxidation of said substrate, whereby a silicon dioxide layer is provided thereon.
Claim 3
Dependent Claim
15 words
The method of claim 1, wherein said halogenated hydrocarbon gas comprises a halogenated alkane gas.
Claim 4
Dependent Claim
14 words
The method of claim 2, wherein said halogenated alkane gas comprises a chlorinated alkane.
Claim 5
Dependent Claim
12 words
The method of claim 3, wherein said chlorinated alkane gas comprises 1,1,1-trichloroethane.
Claim 6
Dependent Claim
18 words
The method of claim 1, wherein said chamber includes a gas inlet means and a gas outlet means.
Claim 7
Dependent Claim
32 words
The method of claim 5, wherein total gas flow into said inlet means, through said chamber, and out of said outlet means is continuous at approximately 1 to 5 liters per minute.
Claim 8
Dependent Claim
29 words
The method of claim 6, wherein said amount of halogenated hydrocarbon gas ranges from about 1% to about 10% by volume of the total gas flowing through said chamber.
Claim 9
Dependent Claim
25 words
The method of claim 7, wherein said amount ranges from about 6% to about 7% by volume of the total gas flowing through said chamber.
Claim 10
Dependent Claim
19 words
The method of claim 1, wherein said temperature ranges from about 900 degrees Centigrade to about 950 degrees Centigrade.
Claim 11
Dependent Claim
46 words
The method of claim 1, wherein said polycide substrates comprises a single crystal semiconductor layer, an electrically insulating SiO 2 layer overlying said semiconductor layer, a layer of polycrystalline silicon overlying said SiO 2 layer, and a layer of metallic silicide overlying said polycrystalline silicon layer.
Claim 12
Dependent Claim
28 words
The method of claim 10, wherein said metallic silicide is of the formula MSi x , where x is greater than 2 and M is a refractory metal.
Claim 13
Dependent Claim
43 words
The method of claim 10, wherein said metallic silicide is of the formula MSi x , where x ranges from about 2.2 to about 2.6, and M is a metal selected from the group consisting of tantalum, tungsten, titanium, molybdenum and mixtures thereof.
Claim 14
Dependent Claim
71 words
A semiconductor circuit structure, consisting essentially of: a single crystal semiconductor layer; a first electrically insulating SiO 2 layer overlying said semiconductor layer; a layer of doped polycrystalline silicon overlying said SiO 2 layer; a layer of electrically conducting material, said material being a refractory metal silicide, overlying said polycrystalline silicon layer; and a second electrically insulating SiO 2 layer overlying said silicide layer, provided by the method of claim 1.
Claim 15
Dependent Claim
20 words
The structure of claim 13, further comprising a third electrically insulating SiO 2 layer overlying said second SiO 2 layer.
Claim 16
Dependent Claim
43 words
The structure of claim 13, wherein said metal silicide is of the formula MSi x , where x ranges from about 2.2 to about 2.6, and M is a metal selected from the group consisting of tantalum, tungsten, titanium, molybdenum and mixtures thereof.
Claim 17
Dependent Claim
23 words
The structure of claim 13, wherein said doped polysilicon layer and said silicide layer have a combined maximum thickness of about 4500 Angstroms.
Claim 18
Dependent Claim
36 words
The structure of claim 13, wherein said doped polysilicon layer has a thickness ranging from about 1500 to about 2000 Angstroms and said silicide layer has a thickness ranging from about 2500 to about 3000 Angstroms.
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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) | 1989-09-15 | 1990-03-17 | 1990-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-15 | 1994-03-17 | 1994-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-15 | 1998-03-17 | 1998-09-16 | $7700.00 | Window Closed / Lapsed |