US5646058A
Expired / Lapsed
US
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Method for fabricating a self-aligned double-gate MOSFET by selective lateral epitaxy
Assignee: International Business Machines Corp
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Filing: 1996-08-01
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Granted: 1997-07-08
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Expires: 2016-08-01
Abstract
Abstract A novel method of fabricating a double-gate MOSFET structure is disclosed. The method utilizes selective lateral epitaxial growth of silicon into a thin gap formed between two sacrificial dielectric films for accurate thickness control. The sacrificial films are then replaced by a gate material (e.g., polysilicon) such that top and bottom gates are self-aligned to each other and to the channel region. Also disclosed is a self-aligned double-gate MOSFET constructed in accordance with the foregoing method.
Inventors
- 👤 Yuan Taur
- 👤 Hon-Sum Philip Wong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:51
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0321; H10D30/0323; H10D30/60; H10D30/67; H10D30/6729; H10D30/673; H10D30/6733; H10D30/6734
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
201 words
A method for fabricating a double-gate MOSFET, comprising the steps of: providing a silicon substrate; forming an oxide layer on the silicon substrate; forming a sacrificial dielectric film on the oxide layer; forming a spacer film on the sacrificial dielectric film; forming a sacrificial dielectric layer on the spacer film; patterning the sacrificial dielectric layer, the spacer film and the sacrificial dielectric film to form a channel therein; etching the spacer film to form a gap between the sacrificial dielectric layer and the sacrificial dielectric film; etching a slot in the oxide layer to expose the silicon substrate; growing epitaxial silicon in the slot, the channel and the gap, such that the silicon emerges from the gap at its ends; doping exposed regions of the epitaxial silicon; oxidizing the exposed silicon regions; stripping the patterned sacrificial dielectric film and the patterned sacrificial dielectric layer; forming oxide layers of about 100 Å or less on the epitaxial silicon in the regions from which the sacrificial dielectric film was removed; depositing polysilicon to form a top gate in the region formerly occupied by the patterned sacrificial dielectric layer, and a bottom gate in the region formerly occupied by the patterned sacrificial dielectric film.
Claim 2
Independent Claim
201 words
A method for fabricating a double-gate MOSFET, comprising the steps of: providing a silicon substrate; forming an oxide layer on the silicon substrate; forming a sacrificial dielectric film on the oxide layer; forming a spacer film on the sacrificial dielectric film; forming a sacrificial dielectric layer on the spacer film; patterning the sacrificial dielectric layer, the spacer film and the sacrificial dielectric film to form a channel therein; etching the spacer film to form a gap between the sacrificial dielectric layer and the sacrificial dielectric film; etching a slot in the oxide layer to expose the silicon substrate; growing epitaxial silicon in the slot, the channel and the gap, such that the silicon emerges from the gap at its ends; doping exposed regions of the epitaxial silicon; oxidizing the exposed silicon regions; stripping the patterned sacrificial dielectric film and the patterned sacrificial dielectric layer; forming oxide layers of about 100 Å or less on the epitaxial silicon in the regions from which the sacrificial dielectric film was removed; depositing polysilicon to form a top gate in the region formerly occupied by the patterned sacrificial dielectric layer, and a bottom gate in the region formerly occupied by the patterned sacrificial dielectric film.
Claim 3
Dependent Claim
14 words
The method of claim 1, wherein the sacrificial dielectric film is a nitride film.
Claim 4
Dependent Claim
14 words
The method of claim 1, wherein the sacrificial dielectric layer is a nitride layer.
Claim 5
Dependent Claim
13 words
The method of claim 1, wherein the spacer film is an oxide film.
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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) | 2000-07-07 | 2001-01-06 | 2001-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-07 | 2005-01-06 | 2005-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-07 | 2009-01-06 | 2009-07-08 | $7700.00 | Window Closed / Lapsed |