US5923046A
Expired / Lapsed
US
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Quantum dot memory cell
Assignee: Toshiba Corp
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Filing: 1997-09-03
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Granted: 1999-07-13
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Expires: 2017-09-03
Abstract
Abstract A channel layer and a spacer layer form a heterojunction therebetween. A V-shaped groove is formed in the spacer layer. The sharp bottom of the V-shaped is located above the heterojunction interface. On the bottom of the V-shaped groove a plurality of quantum dots are formed in a line and discretely. A gate electrode is formed above the quantum dots. A source electrode is connected to the heterojunction interface to form an ohmic contact therebetween. A drain electrode is connected to the heterojunction interface to form an ohmic contact therebetween. The quantum dots are arranged between the source and drain electrodes.
Inventors
- 👤 Tsutomu Tezuka
- 👤 Atsushi Kurobe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:37
CPC Classifications
B; B82; B82Y; B82Y10/00; H; H10; H10D; H10D30/00; H10D30/40; H10D30/402; H10D30/60; H10D30/68; H10D30/681; H10D30/683; G; G11; G11C; G11C2216/00; G11C2216/02; G11C2216/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
A memory cell comprising: a channel layer of a first semiconductor; a spacer layer formed on the channel layer, the spacer layer comprising of a second semiconductor that is dissimilar to the first semiconductor-to form a heterojunction interface therebetween; a V-shaped groove formed in the spacer layer, the bottom of the V-shaped groove being located above the heterojunction interface between the channel layer and the spacer layer; a gate oxide formed in the V-shaped groove; a plurality of quantum dots buried in the gate oxide; a gate electrode formed on the gate oxide; a source electrode connected to the heterojunction interface to form an ohmic contact therebetween; and a drain electrode connected to the heterojunction interface to form an ohmic contact therebetween, the drain electrode being spaced away from the source electrode so that the quantum dots are arranged therebetween.
Claim 2
Dependent Claim
140 words
A memory cell comprising: a channel layer of a first semiconductor; a spacer layer formed on the channel layer, the spacer layer comprising of a second semiconductor that is dissimilar to the first semiconductor-to form a heterojunction interface therebetween; a V-shaped groove formed in the spacer layer, the bottom of the V-shaped groove being located above the heterojunction interface between the channel layer and the spacer layer; a gate oxide formed in the V-shaped groove; a plurality of quantum dots buried in the gate oxide; a gate electrode formed on the gate oxide; a source electrode connected to the heterojunction interface to form an ohmic contact therebetween; and a drain electrode connected to the heterojunction interface to form an ohmic contact therebetween, the drain electrode being spaced away from the source electrode so that the quantum dots are arranged therebetween.
Claim 3
Dependent Claim
35 words
The memory cell according to claim 1, wherein the first semiconductor is n-type SiGe, the second semiconductor is n-type silicon, the gate oxide is silicon oxide, and the quantum dots are made of silicon (Si).
Claim 4
Dependent Claim
17 words
The memory cell according to claim 2, wherein the gate electrode is made of n + -poly-Si.
Claim 5
Dependent Claim
41 words
The memory cell according to claim 1, wherein the first semiconductor is strained p-type Si formed on relaxed p-type SiGe, the second semiconductor is relaxed p-type SiGe, the gate oxide is silicon oxide, and the quantum dots are made of silicon.
Claim 6
Dependent Claim
17 words
The memory cell according to claim 4, wherein the gate electrode is made of n + -poly-Si.
References Cited (Backward Citations)
US5362973A
Cited
US5600163A
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JPH07326730A
Cited
US5679962A
Cited
US5670790A
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US5714766A
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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) | 2002-07-12 | 2003-01-11 | 2003-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-07-12 | 2007-01-11 | 2007-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-07-12 | 2011-01-11 | 2011-07-13 | $7700.00 | Window Closed / Lapsed |