US4428066A
Expired / Lapsed
US
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Semiconductor read only memory
Assignee: Toshiba Corp
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Filing: 1981-04-22
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Granted: 1984-01-24
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Expires: 2001-04-22
Abstract
Abstract A semiconductor fused programmable read only memory having a fuse resistor formed on an insulator film of the surface of a substrate. An island region having a conductivity opposite to that of the surrounding region is formed below the fuse resistor for avoiding excess current flow through the substrate.
Inventors
- 👤 Kazuo Kihara
- 👤 Masashi Ikeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:07
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/49; H10W20/493; G; G11; G11C; G11C17/00; G11C17/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
95 words
A semiconductor fused read only memory (ROM) comprising: a substrate of a first conductivity type; an insulator film formed on a surface of said substrate; a plurality of doped regions cooperating with said substrate to form semiconductor elements; a fuse resistor formed on said insulator film and connected in circuit with said semiconductor elements to form said memory; an island region of a second conductivity type opposite to said first conductivity type, formed within said substrate and extending below all of said fuse resistor, said island region being defined by PN junctions from said substrate.
Claim 2
Dependent Claim
95 words
A semiconductor fused read only memory (ROM) comprising: a substrate of a first conductivity type; an insulator film formed on a surface of said substrate; a plurality of doped regions cooperating with said substrate to form semiconductor elements; a fuse resistor formed on said insulator film and connected in circuit with said semiconductor elements to form said memory; an island region of a second conductivity type opposite to said first conductivity type, formed within said substrate and extending below all of said fuse resistor, said island region being defined by PN junctions from said substrate.
Claim 3
Dependent Claim
17 words
A semiconductor fused ROM according to claim 1, wherein said fuse resistor is made of polycrystalline silicon.
Claim 4
Dependent Claim
16 words
A semiconductor fused ROM according to claim 1, wherein said fuse resistor is made of aluminum.
Claim 5
Dependent Claim
16 words
A semiconductor fused ROM according to claim 1, wherein said fuse resistor is made of nichrome.
Claim 6
Dependent Claim
16 words
A semiconductor fused ROM according to claim 1, wherein said fuse resistor is made of molybdenum.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-23 | 1987-07-25 | 1988-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-23 | 1991-07-25 | 1992-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-23 | 1995-07-25 | 1996-01-24 | $7700.00 | Window Closed / Lapsed |