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US6933516B2
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Forming tapered lower electrode phase-change memories
Assignee: Ovonyx Memory Technology LLC
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Filing: 2004-05-05
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Granted: 2005-08-23
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Expires: 2024-05-05
Abstract
Abstract A phase-change memory may have a tapered lower electrode coated with an insulator. The coated, tapered electrode acts as a mask for a self-aligned trench etch to electrically separate adjacent wordlines. In some embodiments, the tapered lower electrode may be formed over a plurality of doped regions, and isotropic etching may be used to taper the electrode as well as part of the underlying doped regions.
Inventors
- 👤 Daniel Xu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:27
CPC Classifications
H; H10; H10N; H10N70/00; H10N70/20; H10N70/231; H10B; H10B63/00; H10B63/20; H10N70/011; H10N70/801; H10N70/821; H10N70/826; H10N70/841; H10N70/8413; H10N70/8418; H10N70/881; H10N70/882; H10N70/8828; G; G11; G11C; G11C2213/00; G11C2213/50; G11C2213/52; G11C2213/70; G11C2213/72
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
43 words
A phase-change memory cell comprising: a substrate; a plurality of layers of different doping levels in the substrate; a tapered lower electrode for the phase-change memory cell over the substrate; and a trench in said layers, on either side of said tapered electrode.
Claim 2
Dependent Claim
43 words
A phase-change memory cell comprising: a substrate; a plurality of layers of different doping levels in the substrate; a tapered lower electrode for the phase-change memory cell over the substrate; and a trench in said layers, on either side of said tapered electrode.
Claim 3
Dependent Claim
11 words
The memory of claim 1 including an insulator over said electrode.
Claim 4
Dependent Claim
23 words
The memory of claim 1 including a substrate under said tapered electrode, said substrate including a lower portion and a tapered upper portion.
Claim 5
Dependent Claim
13 words
The memory of claim 3 wherein said insulator covers said tapered substrate portion.
Claim 6
Dependent Claim
15 words
The memory of claim 4 wherein said lower substrate portion is free of said insulator.
Claim 7
Dependent Claim
14 words
The memory of claim 2 wherein said trenches are self-aligned to said tapered electrode.
Claim 8
Dependent Claim
11 words
The memory of claim 2 wherein said tapered electrode is conical.
Claim 9
Dependent Claim
28 words
The memory of claim 3 wherein said tapered substrate portion includes a first region of a first conductivity type over a second region of a second conductivity type.
Claim 10
Dependent Claim
25 words
The memory of claim 8 wherein said first type is P type and said first region is sandwiched between said second region and said electrode.
Claim 11
Dependent Claim
14 words
The memory of claim 9 including a buried wordline formed in said upper portion.
References Cited (Backward Citations)
US4085498A
Cited
US4599705A
Cited
US4474623A
Cited
US4845533A
Cited
US6014400A
Cited
US6150253A
Cited
US6407004B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2008-08-22 | 2009-02-21 | 2009-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-08-22 | 2013-02-21 | 2013-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-08-22 | 2017-02-21 | 2017-08-23 | $7700.00 | Window Closed / Lapsed |