EP0282022A2
Expired / Lapsed
EP
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Semiconductor memory device
Assignee: Toshiba Corp
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Filing: 1988-03-09
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Granted: —
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Expires: 2008-03-09
Abstract
Abstract Disclosed is a semiconductor memory device containing a number of memory cells each having a floating gate (13), an erase gate (15), and a control gate (17). In a data erasure mode, electrons are discharged from the floating gate (13) into the erase gate electrode (15). In the semiconductor memory device, an insulating film interlaid between the erase gate (15) and the control gate (17) has a three-layered structure consisting of a silicon oxide film (16A), a silicon nitride film (16B), and a silicon oxide film (16C).
Inventors
- 👤 Shinichi C/O Patent Division Tanaka
- 👤 Masayuki C/O Patent Division Hori
- 👤 Noriyoshi C/O Patent Division Tozawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 04:47
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0135; H10D30/00; H10D30/60; H10D30/68; H10D30/681; H10D30/684; H10D30/685
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
100 words
A semiconductor memory device, characterized by a semiconductor substrate (10) of a first conductivity type; a floating gate (13) layered on a first insulating film (12) which is also layered on said substrate; an erase gate (15) partially overlapping with said floating gate (13), with a second insulating film (14) interlaid therebetween; and a control gate (17) layered above said floating gate (13) and said erase gate (15), with a third insulating film (14, 16) of a three-layered structure consisting of a first oxide film, a nitride film, and a second oxide film, said third insulating film being interlaid therebetween.
Claim 2
Dependent Claim
100 words
A semiconductor memory device, characterized by a semiconductor substrate (10) of a first conductivity type; a floating gate (13) layered on a first insulating film (12) which is also layered on said substrate; an erase gate (15) partially overlapping with said floating gate (13), with a second insulating film (14) interlaid therebetween; and a control gate (17) layered above said floating gate (13) and said erase gate (15), with a third insulating film (14, 16) of a three-layered structure consisting of a first oxide film, a nitride film, and a second oxide film, said third insulating film being interlaid therebetween.
Claim 3
Dependent Claim
44 words
A semiconductor memory device according to claim 1, characterized in that said semiconductor substrate (10) is a silicon substrate, and said third insulating film has a three-layered structure consisting of a first silicon oxide film, a nitride film, and a second silicon oxide film.
Claim 4
Dependent Claim
42 words
A semiconductor memory device according to claim 2, characterized in that said first silicon oxide film is more than 400 Angstroms in thickness, said nitride film is more than 150 angstroms, and said second silicon oxide film is more than 50 Angstroms.
Claim 5
Dependent Claim
32 words
A semiconductor memory device according to claim 1, characterized in that said floating gate (13), said erase gate (15), and said control gate (17) are made of polysilicon, and contain an impurity.
Claim 6
Dependent Claim
28 words
A semiconductor memory device according to claim 4, characterized in that an impurity concentration of said floating gate (13) is lower than that of said erase gate (15).
Claim 7
Dependent Claim
46 words
A semiconductor memory device according to claim 4, characterized in that impurity concentrations contained in said erase gate (15) and said control gate (17) are approximately equal to its solution limit, and impurity concentration contained in said floating gate (13) is less than the solution limit.
Claim 8
Dependent Claim
44 words
A semiconductor memory device according to claim 6, characterized in that an impurity concentration of said erase gate (15) and said control gate is 6 × 10²⁰/cm³ or more, and an impurity concentration of said floating gate (13) is less than 6 × 10²⁰/cm³.
References Cited (Backward Citations)
No citation records indexed.
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