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US6130103A
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Method for fabricating ferroelectric integrated circuits
Assignee: NEC Corp
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Filing: 1998-04-17
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Granted: 2000-10-10
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Expires: 2018-04-17
Abstract
Abstract An integrated circuit is formed that contains a ferroelectric element comprising metal oxide material containing at least two metals. Various methods and structures are applied to minimize the degradation of ferroelectric properties caused by hydrogen during fabrication of the circuit. Oxygen is added to the some elements of the integrated circuit to serve as a getter of hydrogen during fabrication steps. To minimize hydrogen degradation, the ferroelectric compound can be fabricated from a liquid precursor containing one or more of the constituent metals in excess of the amount corresponding to a stoichiometrically balanced concentration. A hydrogen barrier layer, preferably comprising titanium nitride, is formed to cover the top of the ferroelectric element. A hydrogen heat treatment in hydrogen gas is performed on the integrated circuit at a temperature from 200 DEG to 350 DEG C. and for a time period not exceeding 30 minutes to minimize degradation of the ferroelectric properties by hydrogen while restoring other properties of the integrated circuit. An oxygen recovery anneal at 800 DEG C. after high-energy hydrogen steps restores ferroelectric properties.
Inventors
- 👤 Joseph D. Cuchiaro
- 👤 Akira Furuya
- 👤 Carlos A. Paz de Araujo
- 👤 Yoichi Miyasaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:07
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10P; H10P14/00; H10P14/60; H10P14/65; H10P14/6516; G; G11; G11C; G11C11/00; G11C11/21; G11C11/22; H10B; H10B53/00; H10B53/30; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10D64/00; H10D64/01; H10D64/031; H10D64/033; H10P14/6548; H10P14/66; H10P14/662; H10P14/668; H10P14/69; H10P14/692; H10P14/6938; H10P14/6939; H10P14/69393; H10P14/69397; H10P95/00; H10P95/90; H10D1/684; H10P14/63; H10P14/6326; H10P14/6328; H10P14/6334; H10P14/6342; H10P14/69398
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
43 words
A method for fabricating an integrated circuit comprising the steps of: forming an integrated circuit portion including a thin film of metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen for a time period less than 30 minutes.
Claim 2
Independent Claim
43 words
A method for fabricating an integrated circuit comprising the steps of: forming an integrated circuit portion including a thin film of metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen for a time period less than 30 minutes.
Claim 3
Dependent Claim
53 words
A method according to claim 1 and further comprising the step of conducting an oxygen recovery anneal after said step of heating in an atmosphere of hydrogen, said oxygen recovery anneal being performed at a temperature range from 625° C. to 1000° C. for a time period from 20 minutes to 2 hours.
Claim 4
Dependent Claim
37 words
A method according to claim 1 and further comprising the step of forming a hydrogen barrier layer directly over at least a portion of said thin film of ferroelectric metal oxide material before said step of heating.
Claim 5
Dependent Claim
38 words
A method according to claim 1 wherein said ferroelectric metal oxide material comprises an oxide compound containing at least two metals and wherein at least one of said metals is present in said material in an excess amount.
Claim 6
Independent Claim
68 words
A method for fabricating an integrated circuit having a plurality of layers, comprising the steps of: forming an integrated circuit portion including a thin film of ferroelectric metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen at a temperature less than 350° C. for a time period not exceeding 30 minutes, wherein said heating does not result in depositing one of said layers.
Claim 7
Independent Claim
68 words
A method for fabricating an integrated circuit having a plurality of layers, comprising the steps of: forming an integrated circuit portion including a thin film of ferroelectric metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen at a temperature less than 350° C. for a time period not exceeding 30 minutes, wherein said heating does not result in depositing one of said layers.
Claim 8
Dependent Claim
21 words
A method according to claim 5 wherein said step of heating is provided for a time period less than 30 minutes.
Claim 9
Dependent Claim
20 words
A method according to claim 6 wherein said hydrogen comprises from 0.01 to 50 percent in volume of said atmosphere.
Claim 10
Dependent Claim
34 words
A method according to claim 6 and further comprising the step of forming a hydrogen barrier layer directly over at least a portion of said ferroelectric metal oxide material before said step of heating.
Claim 11
Dependent Claim
18 words
A method according to claim 8 wherein said hydrogen barrier layer comprises a nitride of titanium or silicon.
Claim 12
Dependent Claim
38 words
A method according to claim 5 wherein said ferroelectric metal oxide material comprises an oxide compound containing at least two metals and wherein at least one of said metals is present in said material in an excess amount.
Claim 13
Dependent Claim
17 words
A method according to claim 10 wherein said ferroelectric metal oxide material comprises a layered superlattice compound.
Claim 14
Dependent Claim
19 words
A method according to claim 11 wherein said metal present in an excess amount is either niobium or bismuth.
Claim 15
Dependent Claim
16 words
A method according to claim 12 wherein said layered superlattice compound comprises strontium bismuth tantalum niobate.
Claim 16
Dependent Claim
16 words
A method according to claim 13 wherein said metal present in an excess amount is niobium.
Claim 17
Dependent Claim
73 words
A method according to claim 5 wherein said step of forming comprises providing a substrate and a precursor liquid for said ferroelectric metal oxide material, applying said precursor to said substrate and treating it to form said ferroelectric metal oxide material, and further wherein said ferroelectric metal oxide material comprises an oxide compound containing at least two metals and wherein one of said metals is present in said precursor in an excess amount.
Claim 18
Dependent Claim
29 words
A method according to claim 15 wherein said metal present in an excess amount is a metal that does not form volatile compounds that dissipate during said fabrication process.
Claim 19
Dependent Claim
89 words
A method according to claim 5 wherein said step of forming comprises providing a substrate and a precursor liquid for said ferroelectric metal oxide material; applying said precursor to said substrate; and treating said precursor to form said ferroelectric metal oxide material, and further wherein said ferroelectric metal oxide material comprises strontium bismuth tantalum niobate and said precursor contains the chemical elements strontium, bismuth, tantalum and niobium having relative molar proportions corresponding approximately to the stoichiometric formula SrBi 2 .18 Ta 2-x Nb x O 9 , where 0≦×≦2.
Claim 20
Dependent Claim
43 words
A method according to claim 17 wherein said precursor contains an additional amount of bismuth corresponding to between zero percent and 40 percent above the stoichiometric amount represented by the formula SrBi 2 .18 Ta 2-x Nb x O 9 , where 0≦×≦2.
Claim 21
Dependent Claim
38 words
A method according to claim 17, wherein said precursor contains relative molar proportions of the elements strontium, bismuth, tantalum and niobium corresponding approximately to the formula SrBi 2 .18 Ta 1 .44 Nb 0 .56 O 9 .
Claim 22
Dependent Claim
43 words
A method according to claim 19 wherein said precursor contains an additional amount of niobium corresponding to between zero percent and 40 percent above the stoichiometric amount represented by the formula SrB 2 .18 Ta 1 .44 Nb 0 .50 O 9 .
Claim 23
Dependent Claim
53 words
A method according to claim 5 and further comprising the step of performing an oxygen recovery anneal after said step of heating in an atmosphere of hydrogen, said oxygen recovery anneal being performed at a temperature range from 625° C. to 1000° C. for a time period from 20 minutes to 2 hours.
Claim 24
Independent Claim
115 words
A method of fabricating an integrated circuit that includes a thin film of ferroelectric metal oxide material, said method comprising the steps of: forming a portion of said integrated circuit including said thin film of ferroelectric metal oxide material, said metal oxide material comprising a layered superlattice compound having an excess amount of a B-site element; exposing said portion of said integrated circuit to hydrogen; performing an oxygen recovery anneal at a temperature in the range of from 625° C. to 1000° C. for a time period from 20 minutes to 2 hours; and completing said integrated circuit to include said thin film of ferroelectric metal oxide material in a component of said integrated circuit.
Claim 25
Independent Claim
115 words
A method of fabricating an integrated circuit that includes a thin film of ferroelectric metal oxide material, said method comprising the steps of: forming a portion of said integrated circuit including said thin film of ferroelectric metal oxide material, said metal oxide material comprising a layered superlattice compound having an excess amount of a B-site element; exposing said portion of said integrated circuit to hydrogen; performing an oxygen recovery anneal at a temperature in the range of from 625° C. to 1000° C. for a time period from 20 minutes to 2 hours; and completing said integrated circuit to include said thin film of ferroelectric metal oxide material in a component of said integrated circuit.
Claim 26
Dependent Claim
34 words
A method according to claim 22 and further comprising the step of forming a hydrogen barrier layer directly over at least a portion of said ferroelectric metal oxide material before said step of exposing.
Claim 27
Dependent Claim
18 words
A method according to claim 23 wherein said hydrogen barrier layer comprises a nitride of titanium or silicon.
Claim 28
Dependent Claim
16 words
A method according to claim 22 wherein said layered superlattice compound comprises strontium bismuth tantalum niobate.
Claim 29
Dependent Claim
16 words
A method according to claim 25 wherein said metal present in an excess amount is niobium.
Claim 30
Dependent Claim
17 words
A method according to claim 26 wherein said layered superlattice compound comprises an excess amount of bismuth.
Claim 31
Dependent Claim
45 words
A method according to claim 22 wherein said step of forming comprises providing a substrate and a precursor liquid for said ferroelectric metal oxide material, applying said precursor to said substrate, and treating it to form said thin film of said ferroelectric metal oxide material.
Claim 32
Independent Claim
71 words
A method for fabricating an integrated circuit comprising the steps of: forming an integrated circuit portion including a thin film of metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen at a temperature less than 350° C., wherein said heating is provided for a time period less than 30 minutes and the fraction of hydrogen in the hydrogen atmosphere is from 0.01 percent to 50 percent.
Claim 33
Independent Claim
71 words
A method for fabricating an integrated circuit comprising the steps of: forming an integrated circuit portion including a thin film of metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen at a temperature less than 350° C., wherein said heating is provided for a time period less than 30 minutes and the fraction of hydrogen in the hydrogen atmosphere is from 0.01 percent to 50 percent.
Claim 34
Dependent Claim
33 words
A method according to claim 29 and further comprising the step of forming a hydrogen barrier layer directly over at least a portion of said metal oxide material before said step of heating.
Claim 35
Dependent Claim
18 words
A method according to claim 30 wherein said hydrogen barrier layer comprises a nitride of titanium or silicon.
Claim 36
Independent Claim
122 words
A method for fabricating an integrated circuit comprising the steps of: forming an integrated circuit portion including a thin film of metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen at a temperature less than 350° C., wherein said step of forming comprises providing a substrate and a precursor liquid for said metal oxide material; applying said precursor to said substrate; and treating said precursor to form said metal oxide material, and further wherein said metal oxide material comprises strontium bismuth tantalum niobate and said precursor contains the chemical elements strontium, bismuth, tantalum and niobium having relative molar proportions corresponding approximately to the stoichiometric formula SrB 2 .18 Ta 2-x Nb x O 9 , where 0<×<2.
Claim 37
Independent Claim
122 words
A method for fabricating an integrated circuit comprising the steps of: forming an integrated circuit portion including a thin film of metal oxide material; and heating said integrated circuit portion in an atmosphere including hydrogen at a temperature less than 350° C., wherein said step of forming comprises providing a substrate and a precursor liquid for said metal oxide material; applying said precursor to said substrate; and treating said precursor to form said metal oxide material, and further wherein said metal oxide material comprises strontium bismuth tantalum niobate and said precursor contains the chemical elements strontium, bismuth, tantalum and niobium having relative molar proportions corresponding approximately to the stoichiometric formula SrB 2 .18 Ta 2-x Nb x O 9 , where 0<×<2.
Claim 38
Dependent Claim
43 words
A method according to claim 32 wherein said precursor contains an additional amount of bismuth corresponding to between zero percent and 40 percent above the stoichiometric amount represented by the formula SrBi 2 .18 Ta 2-x Nb x O 9 , where 0≦×≦2.
Claim 39
Dependent Claim
38 words
A method according to claim 32 wherein said precursor contains relative molar proportions of the elements strontium, bismuth, tantalum and niobium corresponding approximately to the formula SrBi 2 .18 Ta 1 .44 Nb 0 .56 O 9 .
Claim 40
Dependent Claim
43 words
A method according to claim 34 wherein said precursor contains an additional amount of niobium corresponding to between zero percent and 40 percent above the stoichiometric amount represented by the formula SrBi 2 .18 Ta 1 .44 Nb 0 .56 O 9 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-10-10 | 2004-04-10 | 2004-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-10 | 2008-04-10 | 2008-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-10 | 2012-04-10 | 2012-10-10 | $7700.00 | Window Closed / Lapsed |