US5393683A
Expired / Lapsed
US
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Method of making semiconductor devices having two-layer gate structure
Assignee: Round Rock Research LLC
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Filing: 1992-05-26
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Granted: 1995-02-28
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Expires: 2012-05-26
Abstract
Abstract The present invention includes a method of forming semiconductor oxide layers and, in particular, gate oxide layers, in MOS semiconductor devices formed on silicon substrates. The method includes the steps of forming a first silicon oxide sublayer on the silicon substrate in an atmosphere including primarily oxygen, and forming a second silicon oxide sublayer over the first sublayer in an atmosphere including primarily nitrous oxide (N 2 O). Preferably, the first and second sublayers represent 80 percent and 20 percent, respectively, of the silicon oxide layer.
Inventors
- 👤 Viju K. Mathews
- 👤 Charles H. Dennison
- 👤 Pierre Fazan
- 👤 Roy Maddox
- 👤 Akram Ditali
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:33
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/01344; H10D64/01346; H10D64/60; H10D64/66; H10D64/68; H10D64/681; H10D64/685; H10D64/693
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
74 words
A method of forming a gate oxide layer on a semiconductor substrate for a MOS semiconductor device, comprising the steps: forming a first gate oxide sublayer on the semiconductor substrate in a first atmosphere including primarily oxygen; and forming a second gate oxide sublayer having a thickness of about 0.95 nm to 3 nm, the second gate oxide sublayer being formed on the first oxide sublayer in a second atmosphere including primarily nitrous oxide.
Claim 2
Independent Claim
74 words
A method of forming a gate oxide layer on a semiconductor substrate for a MOS semiconductor device, comprising the steps: forming a first gate oxide sublayer on the semiconductor substrate in a first atmosphere including primarily oxygen; and forming a second gate oxide sublayer having a thickness of about 0.95 nm to 3 nm, the second gate oxide sublayer being formed on the first oxide sublayer in a second atmosphere including primarily nitrous oxide.
Claim 3
Dependent Claim
21 words
The method of claim 1 in which the first gate oxide sublayer forms a predominant portion of the gate oxide layer.
Claim 4
Dependent Claim
24 words
The method of claim 2 in which the first oxide sublayer forms between about 75 percent and 92 percent of the gate oxide layer.
Claim 5
Dependent Claim
17 words
The method of claim 1 in which the first atmosphere includes substantially pure oxygen or argon-diluted oxygen.
Claim 6
Dependent Claim
19 words
The method of claim 1 in which the gate oxide layer has a thickness greater than about 6.5 nm.
Claim 7
Dependent Claim
21 words
The method of claim 1 in which the semiconductor substrate includes primarily silicon and the gate oxide includes primarily silicon dioxide.
Claim 8
Independent Claim
107 words
A method of forming a composite gate oxide layer on a <100>-oriented lightly doped p-type substrate for a MOS semiconductor device, comprising: providing a first reaction atmosphere containing substantially oxygen; heating the substrate from about a room temp to a first reaction temperature; forming on the substrate a first gate oxide sublayer having a thickness of about 9 nm to 11 nm; heating the substrate from the first reaction temperature to a second reaction temperature; providing a second reaction atmosphere containing substantially nitrous oxide; and forming on the first gate oxide sublayer a second gate oxide sublayer having a thickness of about 0.95 nm to 3 nm.
Claim 9
Independent Claim
107 words
A method of forming a composite gate oxide layer on a <100>-oriented lightly doped p-type substrate for a MOS semiconductor device, comprising: providing a first reaction atmosphere containing substantially oxygen; heating the substrate from about a room temp to a first reaction temperature; forming on the substrate a first gate oxide sublayer having a thickness of about 9 nm to 11 nm; heating the substrate from the first reaction temperature to a second reaction temperature; providing a second reaction atmosphere containing substantially nitrous oxide; and forming on the first gate oxide sublayer a second gate oxide sublayer having a thickness of about 0.95 nm to 3 nm.
Claim 10
Dependent Claim
28 words
The method of claim 7 further including the step of diluting the first reaction atmosphere with Argon such that the first reaction atmosphere contains about 16 percent oxygen.
Claim 11
Dependent Claim
41 words
The method of claim 7 in which the heating from room temperature to the first reaction temperature step is carried out at a rate of about 8° C./minute to about 10° C./minute and the first reaction temperature is about 907° C.
Claim 12
Dependent Claim
30 words
The method of claim 7 in which the first oxide sublayer forming step has a duration of about 25 minutes such that the first sublayer thickness is about 10 nm.
Claim 13
Dependent Claim
22 words
The method of claim 7 in which each forming step is followed by a step of purging the reaction atmosphere with nitrogen.
Claim 14
Dependent Claim
41 words
The method of claim 7 in which the heating from the first reaction temperature to the second reaction temperature step is carried out at a rate of about 10° C./minute and the second reaction temperature is greater than about 1000° C.
Claim 15
Dependent Claim
17 words
The method of claim 9 in which the second reaction atmosphere is about 99.9 percent nitrous oxide.
Claim 16
Dependent Claim
30 words
The method of claim 7 in which the second oxide sublayer forming step has a duration of about 10 minutes such that the first sublayer thickness is about 2.0 nm.
Claim 17
Dependent Claim
38 words
The method of claim 7 in which the second gate oxide forming step is followed by a step of cooling the substrate from to the second reaction temperature to room temperature at a rate of about 3.8° C./minute.
Claim 18
Independent Claim
106 words
A method of forming a gate oxide layer of a selected thickness on a semiconductor substrate for a MOS semiconductor device, comprising the steps: forming a first gate oxide sublayer on the semiconductor substrate in a first atmosphere including primarily oxygen; and forming a second gate oxide sublayer on the first oxide sublayer in a second atmosphere including primarily nitrous oxide, the first gate oxide sublayer having a thickness of between about 75 and 92 percent the selected thickness of the gate oxide layer and the second gate oxide sublayer having a corresponding thickness of between about 25 percent and 8 percent of the selected thickness.
Claim 19
Independent Claim
106 words
A method of forming a gate oxide layer of a selected thickness on a semiconductor substrate for a MOS semiconductor device, comprising the steps: forming a first gate oxide sublayer on the semiconductor substrate in a first atmosphere including primarily oxygen; and forming a second gate oxide sublayer on the first oxide sublayer in a second atmosphere including primarily nitrous oxide, the first gate oxide sublayer having a thickness of between about 75 and 92 percent the selected thickness of the gate oxide layer and the second gate oxide sublayer having a corresponding thickness of between about 25 percent and 8 percent of the selected thickness.
Claim 20
Dependent Claim
17 words
The method of claim 16 in which the first atmosphere includes substantially pure oxygen or argon-diluted oxygen.
Claim 21
Dependent Claim
21 words
The method of claim 16 in which the selected thickness of the gate oxide layer is greater than about 6.5 nm.
Claim 22
Dependent Claim
21 words
The method of claim 16 in which the semiconductor substrate includes primarily silicon and the gate oxide includes primarily silicon dioxide.
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