US5833745A
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Bi-based ferroelectric composition and thin film, method for forming the thin film, and non-volatile memory
Assignee: Mitsubishi Materials Corp
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Filing: 1996-11-15
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Granted: 1998-11-10
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Expires: 2016-11-15
Abstract
Abstract A composition for forming a film, comprising a solution of metal compounds in an organic solvent, wherein a molar ratio of metals in said solution is (Sr1-nRn):Bi:(TaYNb1-Y)=X:Q:2, R is at least one element selected from the group consisting of La, Ce, Pr, Nd, Eu, Sm, Tb, Gd and Er, and 0<n</=0.1, 0.4</=X<1, 0</=Y</=1 and 1.5</=Q</=3.5, can be used to form a ferroelectric film. This ferroelectric film is useful in a ferroelectric capacitor, particularly a ferroelectric capacitor for a non-volatile memory.
Inventors
- 👤 Tsutomu Atsuki
- 👤 Tadashi Yonezawa
- 👤 Katsumi Ogi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:19
CPC Classifications
H; H10; H10B; H10B53/00; H10B53/30; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10D1/684
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
62 words
A composition for forming a film, comprising a solution of metal compounds in an organic solvent, wherein a molar ratio of metals in said solution is (Sr 1-n R n ):Bi:(Ta y Nb 1-y )=X:Q:2, R is at least one element selected from the group consisting of La, Ce, Pr, Nd, Eu, Sm, Tb, Gd and Er, 0<n≦0.1, 0.4≦X≦1, 0≦Y≦1 and 1.5≦Q≦3.5.
Claim 2
Dependent Claim
62 words
A composition for forming a film, comprising a solution of metal compounds in an organic solvent, wherein a molar ratio of metals in said solution is (Sr 1-n R n ):Bi:(Ta y Nb 1-y )=X:Q:2, R is at least one element selected from the group consisting of La, Ce, Pr, Nd, Eu, Sm, Tb, Gd and Er, 0<n≦0.1, 0.4≦X≦1, 0≦Y≦1 and 1.5≦Q≦3.5.
Claim 3
Dependent Claim
25 words
The composition of claim 1, wherein the metal compounds in said solution are present in a total concentration of 5 to 15 percent by weight.
Claim 4
Dependent Claim
32 words
A method for forming a ferroelectric film, comprising: applying the composition of claim 1 to a substrate, thereby forming a layer; drying and calcining said layer; and crystallizing said layer by burning.
Claim 5
Dependent Claim
16 words
The method of claim 3, wherein the substrate is not heat treated prior to said applying.
Claim 6
Dependent Claim
37 words
The method of claim 3, wherein said calcining is performed at 200° to 400° C. for 1 to 30 minutes, and said burning is performed at 600° C. to 800° C. for 20 minutes to 2 hours.
Claim 7
Dependent Claim
10 words
A ferroelectric film prepared by the process of claim 3.
Claim 8
Dependent Claim
19 words
The ferroelectric film of claim 6, wherein said ferroelectric film has a thickness of 10 nm to 1 μm.
Claim 9
Dependent Claim
80 words
A ferroelectric film comprising: (i) an undercoat layer having a thickness of 5 to 50 nm and comprising Bi 2 (Ta r Nb 1-r ) 2 O 8 , wherein 0≦r≦1; and (ii) a main layer, formed on said under coat layer, comprising ((Sr 1-m A m ) x Bi 1-x )Bi 2 (Ta y Nb 1-Y ) 2 oxide, wherein 0≦m≦0.3, 0.4≦X≦1, 0≦Y≦1 and A is at least one element selected from the group consisting of Pb and Ba.
Claim 10
Dependent Claim
80 words
A ferroelectric film comprising: (i) an undercoat layer having a thickness of 5 to 50 nm and comprising Bi 2 (Ta r Nb 1-r ) 2 O 8 , wherein 0≦r≦1; and (ii) a main layer, formed on said under coat layer, comprising ((Sr 1-m A m ) x Bi 1-x )Bi 2 (Ta y Nb 1-Y ) 2 oxide, wherein 0≦m≦0.3, 0.4≦X≦1, 0≦Y≦1 and A is at least one element selected from the group consisting of Pb and Ba.
Claim 11
Dependent Claim
8 words
The ferroelectric film of claim 8, wherein m=0.
Claim 12
Dependent Claim
39 words
The ferroelectric film of claim 8 further comprising (iii) a top layer, on said main layer, having a thickness of 5 to 50 nm and comprising Bi 2 (Ta r Nb 1-r ) 2 O 8 , wherein 0≦r≦1.
Claim 13
Dependent Claim
39 words
The ferroelectric film of claim 9 further comprising (iii) a top layer, on said main layer, having a thickness of 5 to 50 nm and comprising Bi 2 (Ta r Nb 1-r ) 2 O 8 , wherein 0≦r≦1.
Claim 14
Dependent Claim
19 words
The ferroelectric film of claim 8, wherein said main layer has a thickness of 10 nm to 1 μm.
Claim 15
Dependent Claim
19 words
The ferroelectric film of claim 9, wherein said main layer has a thickness of 10 nm to 1 μm.
Claim 16
Dependent Claim
27 words
A method for forming the ferroelectric film of claim 8, comprising: depositing an undercoat layer on a substrate; and depositing a main layer on said undercoat layer.
Claim 17
Dependent Claim
27 words
A method for forming the ferroelectric film of claim 9, comprising: depositing an undercoat layer on a substrate; and depositing a main layer on said undercoat layer.
Claim 18
Dependent Claim
35 words
A method for forming the ferroelectric film of claim 10, comprising: depositing an undercoat layer on a substrate; depositing a main layer on said undercoat layer; and depositing a top layer on said main layer.
Claim 19
Dependent Claim
35 words
A method for forming the ferroelectric film of claim 11, comprising: depositing an undercoat layer on a substrate; depositing a main layer on said undercoat layer; and depositing a top layer on said main layer.
Claim 20
Dependent Claim
27 words
A method for forming the ferroelectric film of claim 12, comprising: depositing an undercoat layer on a substrate; and depositing a main layer on said undercoat layer.
Claim 21
Dependent Claim
27 words
A method for forming the ferroelectric film of claim 13, comprising: depositing an undercoat layer on a substrate; and depositing a main layer on said undercoat layer.
Claim 22
Dependent Claim
19 words
The method of claim 14, wherein the substrate is not heat treated prior to said depositing said undercoat layer.
Claim 23
Dependent Claim
19 words
The method of claim 15, wherein the substrate is not heat treated prior to said depositing said undercoat layer.
References Cited (Backward Citations)
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