US5389808A
Expired / Lapsed
US
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Non-volatile semiconductor memory with increased capacitance between floating and control gates
Assignee: Toshiba Corp
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Filing: 1994-02-18
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Granted: 1995-02-14
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Expires: 2014-02-18
Abstract
Abstract In a semiconductor device, a first gate electrode and isolation layers are formed on a first gate insulation layer on a p-type silicon semiconductor substrate, and a second gate electrode is formed on the first gate electrode with a second gate insulation layer interposed therebetween. The first gate electrode is constituted by a first polycrystalline silicon layer, a second polycrystalline silicon layer and an etching stopper thin film interposed therebetween. The first gate electrode is formed by anisotropic-etching or selectively etching the second polycrystalline silicon layer, so that the etching stopper is maintained.
Inventors
- 👤 Norihisa Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:06
CPC Classifications
H; H10; H10B; H10B41/00; H10B41/30; H10B69/00; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0411; H10D64/00; H10D64/60; H10D64/66; H10D64/661; H10D64/662
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
173 words
A semiconductor device comprising: a semiconductor substrate; first and second impurity regions, formed in the semiconductor substrate and extending in a first direction, which serve as bit lines; a first gate insulation layer formed on a channel region interposed between the first and second impurity regions; a first gate electrode formed on the first gate insulation layer; two isolation layers formed on the first and second impurity regions; a second gate insulation layer formed on the first gate electrode; and a second gate electrode, formed on the second gate insulation layer and extending in a second direction perpendicular to the first direction, which serves as a word line, the first gate electrode comprising: a first conductive layer; two second conductive layers formed above the first conductive layer; and a thin film, formed between the first and second conductive layers, serving as a stopper when the second conductive layers are formed by etching, in which each of the second conductive layers consists of side wall layers formed along opposed sides of adjacent isolation layers.
Claim 2
Dependent Claim
173 words
A semiconductor device comprising: a semiconductor substrate; first and second impurity regions, formed in the semiconductor substrate and extending in a first direction, which serve as bit lines; a first gate insulation layer formed on a channel region interposed between the first and second impurity regions; a first gate electrode formed on the first gate insulation layer; two isolation layers formed on the first and second impurity regions; a second gate insulation layer formed on the first gate electrode; and a second gate electrode, formed on the second gate insulation layer and extending in a second direction perpendicular to the first direction, which serves as a word line, the first gate electrode comprising: a first conductive layer; two second conductive layers formed above the first conductive layer; and a thin film, formed between the first and second conductive layers, serving as a stopper when the second conductive layers are formed by etching, in which each of the second conductive layers consists of side wall layers formed along opposed sides of adjacent isolation layers.
Claim 3
Dependent Claim
28 words
A semiconductor device according to claim 1, wherein the etching stopper thin film is formed of a non-conductive material and caused to be conductive by doping an impurity.
Claim 4
Dependent Claim
21 words
A semiconductor device according to claim 2, wherein the impurity is selected from a group consisting of P, As and Sb.
Claim 5
Dependent Claim
28 words
A semiconductor device according to claim 1, wherein the etching stopper thin film is formed of a non-conductive material and caused to be conductive by ion-implanting an impurity.
Claim 6
Dependent Claim
21 words
A semiconductor device according to claim 4, wherein the impurity is selected from a group consisting of P, As and Sb.
Claim 7
Dependent Claim
19 words
A semiconductor device according to claim 1, wherein the etching stopper thin film is formed of a refractory metal.
Claim 8
Dependent Claim
20 words
A semiconductor device according to claim 1, further comprising a refractory metal silicide layer formed on the second gate electrode.
Claim 9
Dependent Claim
25 words
A semiconductor device according to claim 7, wherein the refractory metal silicide is selected from a group consisting of WSi, MoSi, TiSi, TaSi and NbSi.
Claim 10
Dependent Claim
57 words
A semiconductor device according to claim 1, wherein the following formula (1) is satisfied: (y.sub.1 -2x.sub.1)/2<z.sub.1 ( 1) where x 1 : a maximum thickness of a sidewall, y 1 : a maximum width of the first gate electrode, and z 1 : a thickness of a portion of the second gate electrode above the isolation layer.
Claim 11
Dependent Claim
20 words
A semiconductor device according to claim 9, further comprising a refractory metal silicide layer formed on the second gate electrode.
Claim 12
Dependent Claim
25 words
A semiconductor device according to claim 10, wherein the refractory metal silicide is selected from a group consisting of WSi, MoSi, TiSi, TaSi and NbSi.
Claim 13
Dependent Claim
171 words
A semiconductor device comprising: a semiconductor substrate; first and second impurity regions, formed in the semiconductor substrate and extending in a first direction, which serve as bit lines; a first gate insulation layer formed on a channel region interposed between the first and second impurity regions; a first gate electrode formed on the first gate insulation layer; two isolation layers formed on the first and second impurity regions; a second gate insulation layer formed on the first gate electrode; and a second gate electrode, formed on the second gate insulation layer and extending in a second direction perpendicular to the first direction, which serves as a word line, the first gate electrode comprising: a first conductive layer; a second conductive layer formed above the first conductive layer; and a thin film, formed between the first and second conductive layers, serving as a stopper when the second conductive layers are formed by etching, in which each of the second conductive layers is formed along one of opposed side of adjacent isolation layers.
Claim 14
Dependent Claim
171 words
A semiconductor device comprising: a semiconductor substrate; first and second impurity regions, formed in the semiconductor substrate and extending in a first direction, which serve as bit lines; a first gate insulation layer formed on a channel region interposed between the first and second impurity regions; a first gate electrode formed on the first gate insulation layer; two isolation layers formed on the first and second impurity regions; a second gate insulation layer formed on the first gate electrode; and a second gate electrode, formed on the second gate insulation layer and extending in a second direction perpendicular to the first direction, which serves as a word line, the first gate electrode comprising: a first conductive layer; a second conductive layer formed above the first conductive layer; and a thin film, formed between the first and second conductive layers, serving as a stopper when the second conductive layers are formed by etching, in which each of the second conductive layers is formed along one of opposed side of adjacent isolation layers.
Claim 15
Dependent Claim
28 words
A semiconductor device according to claim 12, wherein the etching stopper thin film is formed of a non-conductive material and caused to be conductive by doping an impurity.
Claim 16
Dependent Claim
21 words
A semiconductor device according to claim 13, wherein the impurity is selected from a group consisting of P, As and Sb.
Claim 17
Dependent Claim
28 words
A semiconductor device according to claim 12, wherein the etching stopper thin film is formed of a non-conductive material and caused to be conductive by ion-implanting an impurity.
Claim 18
Dependent Claim
21 words
A semiconductor device according to claim 15, wherein the impurity is selected from a group consisting of P, As and Sb.
Claim 19
Dependent Claim
19 words
A semiconductor device according to claim 12, wherein the etching stopper thin film is formed of a refractory metal.
Claim 20
Dependent Claim
20 words
A semiconductor device according to claim 12, further comprising a refractory metal silicide layer formed on the second gate electrode.
Claim 21
Dependent Claim
25 words
A semiconductor device according to claim 18, wherein the refractory metal silicide is selected from a group consisting of WSi, MoSi, TiSi, TaSi and NbSi.
Claim 22
Dependent Claim
60 words
A semiconductor device according to claim 12, wherein the following formula (2) is satisfied: y.sub.2 -2z.sub.2 <x.sub.2 ( 2) where x 2 : a minimum width of the first gate electrode, y 2 : a maximum width of the first gate electrode, and z 2 : a thickness of a portion of the second gate electrode above the isolation layer.
Claim 23
Dependent Claim
20 words
A semiconductor device according to claim 20, further comprising a refractory metal silicide layer formed on the second gate electrode.
Claim 24
Dependent Claim
25 words
A semiconductor device according to claim 21, wherein the refractory metal silicide is selected from a group consisting of WSi, MoSi, TiSi, TaSi and NbSi.
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