US5897354A
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US
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Method of forming a non-volatile memory device with ramped tunnel dielectric layer
Assignee: Monterey Research LLC
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Filing: 1996-12-17
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Granted: 1999-04-27
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Expires: 2016-12-17
Abstract
Abstract The invention relates to a method of forming a non-volatile memory device with a ramped tunnel dielectric layer, in which a floating gate material layer is being oxidized such that a tunnel dielectric layer is formed having a thickness at a drain region edge which is greater than a thickness at a source region edge.
Inventors
- 👤 Mark T. Kachelmeier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:41
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0411; H10D30/60; H10D30/68; H10D30/6891; Y; Y10; Y10S; Y10S438/00; Y10S438/981
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
74 words
A method of forming a non-volatile memory device comprising: i) forming a gate mask on a source region edge of a patterned floating gate material layer, leaving a drain region edge of said patterned floating gate material layer exposed; and ii) oxidizing said floating gate material layer such that a tunnel dielectric layer is formed having a thickness at a drain region edge which is greater than a thickness at a source region edge.
Claim 2
Independent Claim
74 words
A method of forming a non-volatile memory device comprising: i) forming a gate mask on a source region edge of a patterned floating gate material layer, leaving a drain region edge of said patterned floating gate material layer exposed; and ii) oxidizing said floating gate material layer such that a tunnel dielectric layer is formed having a thickness at a drain region edge which is greater than a thickness at a source region edge.
Claim 3
Dependent Claim
15 words
The method of claim 1, wherein said gate mask is Si 3 N 4 .
Claim 4
Dependent Claim
40 words
The method of claim 1, wherein said tunnel dielectric layer comprises a material selected from the group consisting of silicon dioxide, silicon oxynitride (SiO x N y ), metal nitrides, V 2 O 5 , tetraethylorthosilicate-based oxides and titanium oxide.
Claim 5
Dependent Claim
16 words
The method of claim 3, wherein said tunnel dielectric layer comprises Si 3 N 4 .
Claim 6
Dependent Claim
34 words
The method of claim 1, wherein said floating gate material layer comprises a material selected from the group consisting of amorphous silicon, polysilicon, WSi x , Al, W, Ti, Zr, Mo and TiW alloy.
Claim 7
Dependent Claim
58 words
The method of claim 1, wherein said tunnel dielectric thickness from said source region edge to said drain region edge does not decrease, such that at any point along a length of a channel, said tunnel dielectric thickness on the drain region side of said point is≧the tunnel dielectric thickness on the source region side of said point.
Claim 8
Dependent Claim
25 words
The method of claim 1, wherein said drain region edge thickness and said source region edge thickness are in a ratio of >1:1 and ≦100:1.
Claim 9
Dependent Claim
10 words
The method of claim 7 wherein said ratio is ≧1.1:1.
Claim 10
Dependent Claim
22 words
The method of claim 1, further comprising forming a control gate comprising an interpoly dielectric layer and a control gate material layer.
Claim 11
Dependent Claim
59 words
The method of claim 1, further comprising forming a control gate comprising an interpoly dielectric layer and a control gate material layer, wherein said interpoly dielectric layer comprises a material selected from the group consisting of silicon dioxide, oxide/nitride/oxide (ONO), silicon oxynitride (SiO x N y ), metal nitrides, V 2 O 5 , tetraethylorthosilicate-based oxides and titanium oxide.
Claim 12
Dependent Claim
16 words
The method of claim 10, wherein said interpoly dielectric layer comprises Si 3 N 4 .
Claim 13
Dependent Claim
51 words
The method of claim 1, further comprising forming a control gate comprising an interpoly dielectric layer and a control gate material layer, wherein said control gate material layer comprises a material selected from the group consisting of amorphous silicon, polysilicon, WSi x , Al, W, Ti, Zr, Mo and TiW alloy.
Claim 14
Dependent Claim
58 words
The method of claim 1, further comprising forming a control gate comprising an interpoly dielectric layer and a control gate material layer, wherein said interpoly dielectric layer has a source region edge and a drain region edge and wherein said interpoly dielectric layer has a thickness at the drain region edge greater than at the source region edge.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-04-26 | 2002-10-26 | 2003-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-04-26 | 2006-10-26 | 2007-04-27 | $3760.00 | Window Closed / Lapsed |
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