US5392237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor memory device with EEPROM in trench with polysilicon/metal contacting to source and drain in virtual ground type array
Assignee: Rohm Co Ltd
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Filing: 1993-07-27
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Granted: 1995-02-21
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Expires: 2013-07-27
Abstract
Abstract Provided is a semiconductor memory device wherein nonvolatile memory elements are arranged in a matrix configuration, each of the memory elements having a field effect transistor including a floating gate, an interlayer insulating film and a control gate electrode which are stacked on an insulating film covering a semiconductor substrate, and a source region and a drain region which are respectively formed in the semiconductor substrate on both sides of the gate electrode, the floating gate, interlayer insulating film and control gate electrode being formed in a recess provided in the semiconductor substrate. The semiconductor device of such a structure is reduced in size and highly integrated with its high-performance characteristics maintained.
Inventors
- 👤 Kunio Iida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:50
CPC Classifications
H; H10; H10B; H10B69/00; G; G11; G11C; G11C16/00; G11C16/02; G11C16/04; G11C16/0408; G11C16/0416
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
122 words
A semiconductor memory device comprising: a plurality of nonvolatile memory elements arranged in a matrix configuration, each of the memory elements having a field effect transistor including a floating gate, an interlayer insulating film and a control gate electrode which are sequentially stacked on an insulating film covering a semiconductor substrate; a plurality of pairs of source and drain regions respectively formed in the semiconductor substrate on both sides of the gate electrode; polysilicon lines formed on the substrate, said polysilicon lines electrically connect the source regions; and polysilicon electrodes formed on the drain regions upon which metal lines are connected, wherein the floating gate, interlayer insulating film and control gate electrode being formed in a recess provided in the semiconductor substrate.
Claim 2
Dependent Claim
122 words
A semiconductor memory device comprising: a plurality of nonvolatile memory elements arranged in a matrix configuration, each of the memory elements having a field effect transistor including a floating gate, an interlayer insulating film and a control gate electrode which are sequentially stacked on an insulating film covering a semiconductor substrate; a plurality of pairs of source and drain regions respectively formed in the semiconductor substrate on both sides of the gate electrode; polysilicon lines formed on the substrate, said polysilicon lines electrically connect the source regions; and polysilicon electrodes formed on the drain regions upon which metal lines are connected, wherein the floating gate, interlayer insulating film and control gate electrode being formed in a recess provided in the semiconductor substrate.
Claim 3
Dependent Claim
77 words
The semiconductor memory device of claim 1, further comprising a plurality of three-layered polysilicon structures, each having a first polysilicon film forming a source line, from one of the polysilicon lines, arranged vertically or transversely, a second polysilicon film forming said floating gate of each of said memory elements, and a third polysilicon film forming a word line through which the control gate electrodes of the memory elements arranged vertically or transversely are connected with one another.
Claim 4
Dependent Claim
23 words
The semiconductor memory device of claim 2, wherein said first and/or third polysilicon films are of a three-layered structure of doped polysilicon-tungsten silicide-polysilicon.
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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) | 1998-02-20 | 1998-08-22 | 1999-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-20 | 2002-08-22 | 2003-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-20 | 2006-08-22 | 2007-02-21 | $7700.00 | Window Closed / Lapsed |