EP0031238A2
Expired / Lapsed
EP
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Semiconductor memory device
Assignee: Fujitsu Ltd
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Filing: 1980-12-16
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Granted: —
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Expires: 2000-12-16
Abstract
Abstract A semiconductor memory device of a one-transistor type is disclosed. This device, which is manufactured by using so-called double-layer technology, comprises a buried-channel type transistor (Qi) having normally-off characteristics and a capacitor (Q 2 ) having normally-on characteristics. In addition, an insulating layer (3a') between two conductive layers (6a, 6b) of the transistor (Q 1 ) and the capacitor (Q 2 ) is relatively thick.
Inventors
- 👤 Masao Taguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 15:37
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/637; G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/404; H10B; H10B12/00; H10B12/30; H10D84/00; H10D84/80; H10D84/82; H10D84/83; H10D84/84
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
194 words
A semiconductor memory device of a one-transistor type, characterised by a semiconductor substrate (1) of a first conductivity type including therein first and second impurity doped regions (7, 5a) of a second conductivity type opposite t Q the first conductivity type, the second'impurity doped region having a higher concentration than the first impurity region; a first insulating layer (3b) disposed partly over the first impurity region; a first conductive layer (6b) disposed on the first insulating layer; a second insulating layer (3a') having a thin portion disposed directly on the first impurity doped region and having a thick portion extended over the first conductive layer; a second conductive layer (6a) disposed on the second insulating layer; a buried-channel type transistor (Q1) having normally-off characteristics comprising a source and a drain formed by the first and second impurity doped regions and a channel formed by the first impurity doped region directly below the second conductive layer which serves as a gate electrode thereof; and a capacitor (Q 2 ) having normally-on characteristics comprising a first electrode formed by the first impurity doped region (7) and a second electrode formed by the first conductive layer (6b).
Claim 2
Dependent Claim
194 words
A semiconductor memory device of a one-transistor type, characterised by a semiconductor substrate (1) of a first conductivity type including therein first and second impurity doped regions (7, 5a) of a second conductivity type opposite t Q the first conductivity type, the second'impurity doped region having a higher concentration than the first impurity region; a first insulating layer (3b) disposed partly over the first impurity region; a first conductive layer (6b) disposed on the first insulating layer; a second insulating layer (3a') having a thin portion disposed directly on the first impurity doped region and having a thick portion extended over the first conductive layer; a second conductive layer (6a) disposed on the second insulating layer; a buried-channel type transistor (Q1) having normally-off characteristics comprising a source and a drain formed by the first and second impurity doped regions and a channel formed by the first impurity doped region directly below the second conductive layer which serves as a gate electrode thereof; and a capacitor (Q 2 ) having normally-on characteristics comprising a first electrode formed by the first impurity doped region (7) and a second electrode formed by the first conductive layer (6b).
Claim 3
Dependent Claim
39 words
A device as claimed in Claim 1, characterised in that the difference in work functions between the second conductive layer (6a) and the semiconductor substrate (1) is larger than that between the first conductive layer (6b) and semiconductor substrate.
Claim 4
Dependent Claim
30 words
A device as claimed in Claim 1 or Claim 2, characterised in that stationary charges are introduced into the second insulating layer (3a') directly below the second conductive layer (6a).
Claim 5
Independent Claim
20 words
A device as claimed in any preceding claim, characterised in that the semiconductor substrate (1) is made of monocrystalline silicon.
Claim 6
Dependent Claim
41 words
A device as claimed in Claim 2, characterised in that the semiconductor substrate (1), the first (6b) and second (6a) conductive layers are made of p-type monocrystalline silicon, n-type impurity doped polycrystalline silicon and p-type impurity strongly doped polycrystalline silicon, respectively.
Claim 7
Dependent Claim
35 words
A device as claimed in Claim 2, characterised in that the semiconductor substrate (1), the first (6b) and second (6a) conductive layers are made ofp-type monocrystalline silicon, n-type impurity doped polycrystalline silicon and metal, respectively.
Claim 8
Dependent Claim
37 words
A device as claimed in Claim 2, characterised in that the semiconductor substrate (1), the first (6b) and second (6a) conductive layers are made of p-type monocrystalline silicon, n-type impurity doped polycrystalline silicon and metal silicide, respectively.
Claim 9
Dependent Claim
15 words
A device as claimed in Claim 6, characterised in that the metal is molybdenum (Mo).
Claim 10
Dependent Claim
15 words
A device as claimed in Claim 6, characterised in that the metal is gold (Au).
Claim 11
Dependent Claim
15 words
A device as claimed in Claim 6, characterised in that the metal is tungsten (W).
Claim 12
Dependent Claim
15 words
A device as claimed in Claim 6, characterised in that the metal is titanium (Ti).
Claim 13
Dependent Claim
23 words
A device as claimed in Claim 3, characterised in that the first (6b) and second (6a) conductive layers are made of polycrystalline silicon.
Claim 14
Dependent Claim
23 words
A device as claimed in Claim 3, characterised in that the first insulating layer (3b) is made of silicon dioxide (Si0 2 ).
Claim 15
Dependent Claim
21 words
A device as claimed in Claim 3, characterised in that the first insulating layer (3b) is made of silicon nitride (Si3N4).
Claim 16
Dependent Claim
25 words
A device as claimed in Claim 3, characterised in that the second insulating layer (3a') is made of alumina ( A1 2 0 3 ).
Claim 17
Dependent Claim
21 words
A device as claimed in Claim 3, characterised in that the second insulating layer (3a') is made of tantalum oxide (Ta205).
Claim 18
Dependent Claim
27 words
A device as claimed in Claim 15, characterised by a third insulating layer (3a'-2) disposed on the second insulating layer (3a'-l) over the first conductive layer (6b).
Claim 19
Dependent Claim
23 words
A device as claimed in Claim 1, characterised in that the first (3b) and second (3a') insulating layers are made of silicon dioxide.
Claim 20
Dependent Claim
54 words
A device as claimed in Claim 1, characterised in that the semiconductor substrate (1) and the first conductive layer (6b) are p-type monocrystalline silicon and polycrystalline silicon into which n-type impurities are strongly doped, respectively, and the second insulating layer (3a') is manufactured by thermally oxidizing the semiconductor substrate and the first conductive layer.
References Cited (Backward Citations)
No citation records indexed.
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