EP0025311A2
Expired / Lapsed
EP
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Non-volatile semiconductor memory device
Assignee: Fujitsu Ltd
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Filing: 1980-08-27
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Granted: —
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Expires: 2000-08-27
Abstract
Abstract A non-volatile semiconductor memory device comprises a substrate (1) a source region (3) and a drain region (4); a channel region (5) between the source and drain regions; first and second insulating layers (6, 8) over the channel region; and a floating-gate (7) or traps (7') between the first and second insulating layers. In the first insulating layer the gap of an energy band thereof increases from the region ofthesubs- I trate to the region of the floating-gate or the traps.
Inventors
- 👤 Shinpei Hijiya
- 👤 Takashi Ito
- 👤 Takao Nozaki
- 👤 Hajime Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 07:08
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/68; H10D30/681; H10D30/684; H10D30/686
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
79 words
A non-volatile semiconductor memory device, characterised by a substrate (1) of a first conductivity type; a first insulating layer (6) disposed on the substrate; a second insulating layer (8) disposed over the first insulating layer; and means (7, 7') for storing charges disposed between the first and second insulating layers; and in that the gap of an energy band of the first insulating layer decreases from the region of the charge storing means to the region of the substrate.
Claim 2
Dependent Claim
79 words
A non-volatile semiconductor memory device, characterised by a substrate (1) of a first conductivity type; a first insulating layer (6) disposed on the substrate; a second insulating layer (8) disposed over the first insulating layer; and means (7, 7') for storing charges disposed between the first and second insulating layers; and in that the gap of an energy band of the first insulating layer decreases from the region of the charge storing means to the region of the substrate.
Claim 3
Dependent Claim
17 words
A device according to Claim 1, characterised in that the charge storing means comprises a floating-gate (7).
Claim 4
Dependent Claim
46 words
A device according to Claim 1, characterised in that the materials of the first and second insulating layers (6, 8) are different from each other; and in that the charge storing means comprises traps (7') formed at the interface of the first and second insulating layers.
Claim 5
Dependent Claim
19 words
A device according to Claim 1, characterised in that the first insulating layer (6) comprises thermally oxidized silicon nitride.
Claim 6
Dependent Claim
39 words
A device according to Claim 1, characterised in that the first insulating layer (6) comprises a third insulating layer of silicon nitride on the substrate (1) and a fourth insulating layer of silicon dioxide on the third insulating layer.
Claim 7
Dependent Claim
20 words
A device according to Claim 4 or Claim 5, characterised in that the silicon nitride is thermally grown silicon nitride.
Claim 8
Dependent Claim
21 words
A device according to Claim 4 or Claim 5, characterised in that the silicon nitride is manufactured by chemical vapor deposition.
Claim 9
Independent Claim
19 words
A device according to any preceding claim, characterised in that the second insulating layer (8) is of silicon dioxide.
Claim 10
Independent Claim
20 words
A device according to any preceding claim, characterised by a control gate (9) disposed on the second insulating layer (8).
Claim 11
Dependent Claim
64 words
A device according to Claim 2 or Claim 3, characterised by a source region (3) and a drain region (4) of a second conductivity type,opposite to the first conductivity type,formed in the substrate (1) apart from each other; and a channel region (5) disposed between the source and drain regions in the substrate, the first insulating layer (6) being disposed on the channel region.
Claim 12
Dependent Claim
66 words
A device according to Claim 10, characterised in that a writing operation is performed by causing avalanche breakdown in the vicinity of the drain region (4) and injecting hot carriers of a first type into the floating-gate (7); and in that an erasing operation is performed by causing avalanche breakdown and injecting hot carriers of a second type opposite to said first type into the floating-gate.
Claim 13
Dependent Claim
61 words
A device according to Claim 10, characterised in that a writing operation is performed by tunneling carriers of a first type from the substrate (1) through the first insulating layer (6) to the floating-gate (7); and in that an erasing operation is performed by tunneling carriers of said first type from the floating-gate through the first insulating layer to the substrate.
Claim 14
Dependent Claim
61 words
A device according to Claim 10, characterised in that a writing operation is performed by tunneling carriers of a first type from the substrate (1) through the first insulating layer (6) to the traps (7'); and in that an erasing operation is performed by tunneling carriers of the first type from the traps through the first insulating layer to the substrate.
References Cited (Backward Citations)
No citation records indexed.
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