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US5821005A
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Ferroelectrics thin-film coated substrate and manufacture method thereof and nonvolatile memory comprising a ferroelectrics thinfilm coated substrate
Assignee: Sharp Corp
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Filing: 1996-03-08
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Granted: 1998-10-13
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Expires: 2016-03-08
Abstract
Abstract A ferroelectrics thin-film coated substrate is manufactured in a low-temperature process by using a ferroelectrics having a dense and even surface and exhibiting a large residual spontaneous polarization. A ferroelectrics thin-film coated substrate has a structure with a buffer layer, a growth layer allowing a ferroelectrics thin-film to grow, and a ferroelectrics thin-film made of a ferroelectric material having a layered crystalline structure expressed in the chemical formula Bi2 Am-1 Bm O3m+3 (A is selected from Na1+, K1+, Pb2+, Ca2+, Sr2+, Ba2+, Bi3+ and the like, B is selected from Fe3+, Ti4+, Nb5+, Ta5+, W6+ and Mo6+, and m is an integer not less than 1) formed in succession.
Inventors
- 👤 Takeshi Kijima
- 👤 Sakiko Satoh
- 👤 Hironori Matsunaga
- 👤 Masayoshi Koba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:42
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/22; C23C16/30; C23C16/40; C23C16/02; C23C16/0272
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
196 words
A ferroelectric thin-film coated substrate comprising: a buffer layer; a growth layer for allowing a ferroelectrics thin-film to grow, wherein said growth layer comprises a material having a layered crystal structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 3+ , Nb 5+ , Ta 5+ , W 6+ , and Mo 6+ , and m is an integer not less than 1; and a ferroelectrics thin-film made of ferroelectric material having a layered structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 4+ , Nb 5+ , Ta 5+ , W 6+ , and Mo 6+ , and m is an integer not less than 1; these being successively formed on a substrate.
Claim 2
Dependent Claim
196 words
A ferroelectric thin-film coated substrate comprising: a buffer layer; a growth layer for allowing a ferroelectrics thin-film to grow, wherein said growth layer comprises a material having a layered crystal structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 3+ , Nb 5+ , Ta 5+ , W 6+ , and Mo 6+ , and m is an integer not less than 1; and a ferroelectrics thin-film made of ferroelectric material having a layered structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 4+ , Nb 5+ , Ta 5+ , W 6+ , and Mo 6+ , and m is an integer not less than 1; these being successively formed on a substrate.
Claim 3
Dependent Claim
45 words
The ferroelectrics thin-film coated substrate as set forth in claim 1, wherein said growth layer and said ferroelectrics thin-film comprise the same material and said buffer layer comprises at least one of the elements of the material constituting said growth layer and said ferroelectrics thin-film.
Claim 4
Dependent Claim
40 words
The ferroelectrics thin-film coated substrate as set forth in claim 2, wherein said ferroelectrics thin-film, said growth layer and said buffer layer comprise Bi 4 Ti 3 O 12 , Bi 4 Ti 3 O 12 and titanium oxide, respectively.
Claim 5
Dependent Claim
21 words
A capacitor-structured nonvolatile memory comprising the ferroelectrics thin-film coated substrate as set forth in any of claims 1, 2 or 3.
Claim 6
Dependent Claim
21 words
An MFMIS-FET-structured nonvolatile memory comprising the ferroelectrics thin-film coated substrate as set forth in any of claims 1, 2 or 3.
Claim 7
Independent Claim
239 words
A method for manufacturing a ferroelectrics thin-film coated substrate by forming a buffer layer and a ferroelectrics thin-film on a substrate by the MOCVD process, wherein a growth layer for allowing a ferroelectrics thin-film to grow is formed on the buffer layer after forming a buffer layer and further a ferroelectrics thin-film is formed on the growth layer at lower thin-film forming temperatures than that of the growth layer, wherein said growth layer comprises a material having a layered crystal structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 4+ , Nb 5+ , Ta 5+ , W 6+ , and Mo 6+ , and m is an integer not less than 1; and wherein the ferroelectrics thin-film made of ferroelectric material has a layered structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 4+ , Nb 5+ , Ta 5+ , W 6+ , Mo 6+ , and m is an integer not less than 1.
Claim 8
Independent Claim
239 words
A method for manufacturing a ferroelectrics thin-film coated substrate by forming a buffer layer and a ferroelectrics thin-film on a substrate by the MOCVD process, wherein a growth layer for allowing a ferroelectrics thin-film to grow is formed on the buffer layer after forming a buffer layer and further a ferroelectrics thin-film is formed on the growth layer at lower thin-film forming temperatures than that of the growth layer, wherein said growth layer comprises a material having a layered crystal structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 4+ , Nb 5+ , Ta 5+ , W 6+ , and Mo 6+ , and m is an integer not less than 1; and wherein the ferroelectrics thin-film made of ferroelectric material has a layered structure expressed in a chemical formula Bi 2 A m-1 B m O 3m+3 , wherein A is selected from Na 1+ , K 1+ , Pb 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Bi 3+ , B is selected from Fe 3+ , Ti 4+ , Nb 5+ , Ta 5+ , W 6+ , Mo 6+ , and m is an integer not less than 1.
Claim 9
Dependent Claim
77 words
The method for manufacturing a ferroelectrics thin-film coated substrate as set forth in claim 6, wherein a bismuth-based oxide ferroelectrics thin-film having a layered crystal structure is formed as said ferroelectrics thin-film, a bismuth-based oxide ferroelectrics thin-film of the same material as that of said ferroelectrics thin-film is formed as said growth layer, and a thin-film containing the component elements of the material constituting said growth layer and said ferroelectrics thin-film is formed as said buffer layer.
Claim 10
Dependent Claim
75 words
The method for manufacturing a ferroelectrics thin-film coated substrate as set forth in claim 7, wherein, after forming a titanium oxide thin-film as said buffer layer, a Bi 4 Ti 3 O 12 thin-film is formed at thin-film forming temperatures of 400° C. to 650° C. as said growth layer and a Bi 4 Ti 3 O 12 thin-film is formed at thin-film forming temperatures of 300° C. to 400° C. as said ferroelectrics thin-film.
Claim 11
Dependent Claim
40 words
The method for manufacturing a ferroelectrics thin-film coated substrate as set forth in claim 8, wherein, the thin-film forming temperature of Bi 4 Ti 3 O 12 thin-film of said growth layer is set at 400° C. to 470° C.
Claim 12
Independent Claim
73 words
A method for manufacturing a ferroelectrics thin-film coated substrate by forming a buffer layer and a ferroelectrics thin-film on a substrate by the MOCVD process, wherein after forming a buffer layer on a substrate, a growth layer for growing a ferroelectrics thin-film is formed on the buffer layer, a ferroelectrics thin-film is formed on the growth layer at lower thin-film forming temperatures than that of the growth layer, and heat treatment is applied.
Claim 13
Independent Claim
73 words
A method for manufacturing a ferroelectrics thin-film coated substrate by forming a buffer layer and a ferroelectrics thin-film on a substrate by the MOCVD process, wherein after forming a buffer layer on a substrate, a growth layer for growing a ferroelectrics thin-film is formed on the buffer layer, a ferroelectrics thin-film is formed on the growth layer at lower thin-film forming temperatures than that of the growth layer, and heat treatment is applied.
Claim 14
Dependent Claim
85 words
The method for manufacturing a ferroelectrics thin-film coated substrate as set forth in claim 10, wherein after forming a titanium oxide thin-film as said buffer layer, a Bi 4 Ti 3 O 12 thin-film is formed at thin-film forming temperatures of 400° C. to 650° C. as said growth layer, a Bi 4 Ti 3 O 12 thin-film is formed at thin-film forming temperatures of 300° C. to 400° C. as said ferroelectrics thin-film, and heat treatment at 500° C. to 700° C. is applied.
Claim 15
Dependent Claim
40 words
The method for manufacturing a ferroelectrics thin-film coated substrate as set forth in claim 11, wherein, the thin-film forming temperature of Bi 4 Ti 3 O 12 thin-film of said growth layer is set at 400° C. to 470° C.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-10-12 | 2002-04-13 | 2002-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-12 | 2006-04-13 | 2006-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-10-12 | 2010-04-13 | 2010-10-13 | $7700.00 | Window Closed / Lapsed |