Patent US5672994A successfully refreshed from Google Patents.
US5672994A
Expired / Lapsed
US
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Antifuse circuit using standard MOSFET devices
Assignee: International Business Machines Corp
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Filing: 1995-12-21
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Granted: 1997-09-30
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Expires: 2015-12-21
Abstract
Abstract A programmable device is formed from a field-effect transistor. Specifically, the present invention generally related to integrated circuit (IC) structures and more particularly, to an improved antifuse structure for use in programming redundant and customizable IC chips. The anti-fuse is NFET made of MOS material and formed at a face of a semiconductor layer having an n-type doped source, and drain region, and a p-type doped channel region separating the source and drain regions. The device is programmed by applying a high voltage to the NFET drain to form a hot spot located along the channel width of the drain and thereby forming a bridge, which now has less resistance than the surrounding channel material, to the NFET source.
Inventors
- 👤 Wai-Ming William Au
- 👤 Edward Joseph Nowak
- 👤 Minh Ho Tong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:47
CPC Classifications
G; G11; G11C; G11C17/00; G11C17/14; G11C17/16; H; H10; H10W; H10W20/00; H10W20/40; H10W20/49; H10W20/491
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
77 words
A method for selectively programming a field-effect transistor (FET) having channel, source, and drain regions formed in a semi-conductor layer with a characteristic source-drain breakdown voltage and resistivity, comprising the steps of: a) selecting the FET to be programmed; and b) applying a programming voltage to the drain region, the programming voltage being greater than or equal to the source-drain breakdown voltage of the transistor and the resistivity of the transistor is reduced to about ten kilo-ohms.
Claim 2
Independent Claim
77 words
A method for selectively programming a field-effect transistor (FET) having channel, source, and drain regions formed in a semi-conductor layer with a characteristic source-drain breakdown voltage and resistivity, comprising the steps of: a) selecting the FET to be programmed; and b) applying a programming voltage to the drain region, the programming voltage being greater than or equal to the source-drain breakdown voltage of the transistor and the resistivity of the transistor is reduced to about ten kilo-ohms.
Claim 3
Dependent Claim
12 words
The method of claim 1, wherein the field-effect transistor is an NFET.
Claim 4
Dependent Claim
26 words
The method of claim 1, wherein during the step of applying a programming voltage a bias voltage is applied to the gate of the field-effect transistor.
Claim 5
Independent Claim
78 words
A method for selectively programming a field-effect transistor (FET) having channel, source, and drain regions formed in a semi-conductor layer with a characteristic source-drain breakdown voltage and resistivity, comprising the steps of: a) selecting the FET to be programmed: and b) applying a programming voltage to the drain region, the programming voltage being greater than or equal to the source-drain breakdown voltage of the transistor and resistivity of the transistor is reduced to about one to ten kilo-ohms.
Claim 6
Independent Claim
78 words
A method for selectively programming a field-effect transistor (FET) having channel, source, and drain regions formed in a semi-conductor layer with a characteristic source-drain breakdown voltage and resistivity, comprising the steps of: a) selecting the FET to be programmed: and b) applying a programming voltage to the drain region, the programming voltage being greater than or equal to the source-drain breakdown voltage of the transistor and resistivity of the transistor is reduced to about one to ten kilo-ohms.
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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) | 2000-09-29 | 2001-03-31 | 2001-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-29 | 2005-03-31 | 2005-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-29 | 2009-03-31 | 2009-09-30 | $7700.00 | Window Closed / Lapsed |