US4331968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three layer floating gate memory transistor with erase gate over field oxide region
Assignee: STMicroelectronics lnc USA
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Filing: 1980-03-17
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Granted: 1982-05-25
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Expires: 2000-03-17
Abstract
Abstract A field effect transistor storage device for use in programmable read-only memories of the type employing a floating gate and a control gate overlying and aligned with the floating gate. An erase gate is provided adjacent at least one edge of the floating gate for removing charge stored on the floating gate. A method of electrically erasing the storage device includes holding the control gate at a fixed potential to thereby hold the floating gate at a substantially fixed potential while a relatively low voltage is applied to the erase gate to remove charge stored on the floating gate.
Inventors
- 👤 William M. Gosney, Jr.
- 👤 Vernon G. McKenny
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:18
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/68; H10D30/681; H10D30/684; H10D30/686; G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/10; G11C16/14
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
151 words
A field effect transistor storage device comprising: a semiconductor substrate having a source region, a channel region, and a drain region with a field oxide region surrounding said source, channel, and drain regions; a first dielectric layer over at least said channel region; a floating gate comprising a first polycrystalline silicon layer on said first dielectric layer, and overlying said channel region and a portion of said field oxide region; a second dielectric layer covering the top and edges of said floating gate; a control gate comprising a second polycrystalline silicon layer on said second dielectric layer and overlying said floating gate; a third dielectric layer covering the top and edges of said control gate; and an erase gate comprising a conductive layer adjacent at least one edge of said floating gate which overlies the field oxide region, said erase gate also overlies at least a portion of said control gate.
Claim 2
Dependent Claim
151 words
A field effect transistor storage device comprising: a semiconductor substrate having a source region, a channel region, and a drain region with a field oxide region surrounding said source, channel, and drain regions; a first dielectric layer over at least said channel region; a floating gate comprising a first polycrystalline silicon layer on said first dielectric layer, and overlying said channel region and a portion of said field oxide region; a second dielectric layer covering the top and edges of said floating gate; a control gate comprising a second polycrystalline silicon layer on said second dielectric layer and overlying said floating gate; a third dielectric layer covering the top and edges of said control gate; and an erase gate comprising a conductive layer adjacent at least one edge of said floating gate which overlies the field oxide region, said erase gate also overlies at least a portion of said control gate.
Claim 3
Dependent Claim
62 words
An electrode arrangement according to claim 1 wherein: said erase gate is formed from a third polycrystalline silicon layer deposited on said substrate over said second dielectric layer; and said erase gate is capacitively shielded from said floating gate upper surface by said control gate and said erase gate is electrically isolated from said floating gate edges by said first dielectric layer.
References Cited (Backward Citations)
US3755721A
Cited
US3996657A
Cited
US4115914A
Cited
US4142920A
Cited
US4099196A
Cited
US4203158A
Cited
US4203158B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-24 | 1985-11-23 | 1986-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-24 | 1989-11-23 | 1990-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-24 | 1993-11-23 | 1994-05-25 | $7700.00 | Window Closed / Lapsed |