WO2022210563A1 - 圧電体膜、圧電体膜の製造方法、圧電素子及び圧電デバイス - Google Patents
圧電体膜、圧電体膜の製造方法、圧電素子及び圧電デバイス Download PDFInfo
- Publication number
- WO2022210563A1 WO2022210563A1 PCT/JP2022/015069 JP2022015069W WO2022210563A1 WO 2022210563 A1 WO2022210563 A1 WO 2022210563A1 JP 2022015069 W JP2022015069 W JP 2022015069W WO 2022210563 A1 WO2022210563 A1 WO 2022210563A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- piezoelectric
- film
- layer
- zno
- piezoelectric film
- Prior art date
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- 239000000463 material Substances 0.000 claims abstract description 131
- 239000013078 crystal Substances 0.000 claims abstract description 124
- 239000000654 additive Substances 0.000 claims abstract description 14
- 230000000996 additive effect Effects 0.000 claims abstract description 14
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 8
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 8
- 229910052793 cadmium Inorganic materials 0.000 claims abstract description 6
- 229910052733 gallium Inorganic materials 0.000 claims abstract description 6
- 239000000758 substrate Substances 0.000 claims description 39
- 229910052984 zinc sulfide Inorganic materials 0.000 claims description 38
- 239000007789 gas Substances 0.000 claims description 37
- 238000004544 sputter deposition Methods 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 26
- 229910052760 oxygen Inorganic materials 0.000 claims description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 20
- 239000001301 oxygen Substances 0.000 claims description 20
- 239000000956 alloy Substances 0.000 claims description 2
- 229910045601 alloy Inorganic materials 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 abstract description 6
- 239000010408 film Substances 0.000 description 201
- 239000010410 layer Substances 0.000 description 196
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 135
- 239000011787 zinc oxide Substances 0.000 description 67
- 238000005259 measurement Methods 0.000 description 22
- 230000000052 comparative effect Effects 0.000 description 13
- 239000010409 thin film Substances 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000011701 zinc Substances 0.000 description 10
- 230000008878 coupling Effects 0.000 description 9
- 238000010168 coupling process Methods 0.000 description 9
- 238000005859 coupling reaction Methods 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- 239000004033 plastic Substances 0.000 description 8
- 229920003023 plastic Polymers 0.000 description 8
- 230000010287 polarization Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 6
- 239000010936 titanium Substances 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 239000012790 adhesive layer Substances 0.000 description 5
- 239000004020 conductor Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000005020 polyethylene terephthalate Substances 0.000 description 5
- 229920000139 polyethylene terephthalate Polymers 0.000 description 5
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 238000001755 magnetron sputter deposition Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 238000005001 rutherford backscattering spectroscopy Methods 0.000 description 4
- SKJCKYVIQGBWTN-UHFFFAOYSA-N (4-hydroxyphenyl) methanesulfonate Chemical compound CS(=O)(=O)OC1=CC=C(O)C=C1 SKJCKYVIQGBWTN-UHFFFAOYSA-N 0.000 description 3
- PFNQVRZLDWYSCW-UHFFFAOYSA-N (fluoren-9-ylideneamino) n-naphthalen-1-ylcarbamate Chemical compound C12=CC=CC=C2C2=CC=CC=C2C1=NOC(=O)NC1=CC=CC2=CC=CC=C12 PFNQVRZLDWYSCW-UHFFFAOYSA-N 0.000 description 3
- 239000004925 Acrylic resin Substances 0.000 description 3
- 229920000178 Acrylic resin Polymers 0.000 description 3
- 229920000877 Melamine resin Polymers 0.000 description 3
- 239000005083 Zinc sulfide Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 229910052814 silicon oxide Inorganic materials 0.000 description 3
- 230000001629 suppression Effects 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- MARUHZGHZWCEQU-UHFFFAOYSA-N 5-phenyl-2h-tetrazole Chemical compound C1=CC=CC=C1C1=NNN=N1 MARUHZGHZWCEQU-UHFFFAOYSA-N 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 description 2
- 229920000089 Cyclic olefin copolymer Polymers 0.000 description 2
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 2
- 239000004640 Melamine resin Substances 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000000560 X-ray reflectometry Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 229920000180 alkyd Polymers 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- -1 for example Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 229920000515 polycarbonate Polymers 0.000 description 2
- 239000004417 polycarbonate Substances 0.000 description 2
- 239000011112 polyethylene naphthalate Substances 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- UHYPYGJEEGLRJD-UHFFFAOYSA-N cadmium(2+);selenium(2-) Chemical compound [Se-2].[Cd+2] UHYPYGJEEGLRJD-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- AJNVQOSZGJRYEI-UHFFFAOYSA-N digallium;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Ga+3].[Ga+3] AJNVQOSZGJRYEI-UHFFFAOYSA-N 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- HRHKULZDDYWVBE-UHFFFAOYSA-N indium;oxozinc;tin Chemical compound [In].[Sn].[Zn]=O HRHKULZDDYWVBE-UHFFFAOYSA-N 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 229920003207 poly(ethylene-2,6-naphthalate) Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 150000003346 selenoethers Chemical class 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000005477 sputtering target Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 1
- 238000000427 thin-film deposition Methods 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- YVTHLONGBIQYBO-UHFFFAOYSA-N zinc indium(3+) oxygen(2-) Chemical compound [O--].[Zn++].[In+3] YVTHLONGBIQYBO-UHFFFAOYSA-N 0.000 description 1
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/85—Piezoelectric or electrostrictive active materials
- H10N30/853—Ceramic compositions
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/453—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/62218—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining ceramic films, e.g. by using temporary supports
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/08—Oxides
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/34—Sputtering
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
- C30B23/02—Epitaxial-layer growth
- C30B23/08—Epitaxial-layer growth by condensing ionised vapours
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
- C30B25/02—Epitaxial-layer growth
- C30B25/06—Epitaxial-layer growth by reactive sputtering
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/16—Oxides
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/01—Manufacture or treatment
- H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
- H10N30/074—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
- H10N30/076—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing by vapour phase deposition
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/01—Manufacture or treatment
- H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
- H10N30/074—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
- H10N30/079—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing using intermediate layers, e.g. for growth control
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
- C04B2235/3206—Magnesium oxides or oxide-forming salts thereof
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3284—Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/46—Gases other than oxygen used as reactant, e.g. nitrogen used to make a nitride phase
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/76—Crystal structural characteristics, e.g. symmetry
- C04B2235/762—Cubic symmetry, e.g. beta-SiC
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/77—Density
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/95—Products characterised by their size, e.g. microceramics
Definitions
- the present invention relates to a piezoelectric film, a method for manufacturing a piezoelectric film, a piezoelectric element, and a piezoelectric device.
- piezoelectric elements with piezoelectric films are widely used in, for example, sensors such as pressure sensors and acceleration sensors, high-frequency filter devices, and piezoelectric devices such as piezoelectric actuators.
- the piezoelectric film When a piezoelectric film is formed by growing crystals on a substrate or the like, by orienting the crystals of the piezoelectric film in the c-axis direction, the piezoelectric film has high piezoelectric characteristics, but the film stress increases. The piezoelectric film becomes easy to bend. Therefore, when the base material on which the piezoelectric film is placed is a low-rigidity base material such as PET, the laminated body in which the piezoelectric film is placed on the base material warps. do. On the other hand, if the substrate is a highly rigid substrate such as a Si substrate or a glass substrate, the piezoelectric film is likely to crack, or the substrate and the piezoelectric layer are likely to separate. have an adverse effect on the piezoelectric characteristics of the piezoelectric element.
- a piezoelectric element for example, a piezoelectric element has been disclosed in which a lower electrode layer, an orientation control layer, a piezoelectric layer and an upper electrode layer are laminated in this order on a substrate (see, for example, Patent Document 1).
- the conventional piezoelectric element has the orientation control layer between the lower electrode layer and the piezoelectric layer, lattice matching between the lower electrode layer and the piezoelectric layer is likely to be lost due to the influence of the orientation control layer. There was a problem of becoming If the lattice matching is disrupted, the crystal orientation of the piezoelectric layer is disturbed, making it difficult to increase the orientation of the piezoelectric layer and degrading the piezoelectric characteristics. Since the piezoelectric element operates on the principle of vibration in the thickness direction of the piezoelectric layer (thickness vibration), in order for the piezoelectric layer to exhibit high piezoelectric characteristics, the piezoelectric layers must have the same crystal orientation. It is required to have a highly oriented crystal orientation.
- the orientation control layer itself has a film stress
- the film stress of the orientation control layer acts on the lower electrode layer positioned below the orientation control layer, causing peeling between the lower electrode layer and the orientation control layer,
- cracking of the lower electrode layer, warping of the substrate, and the like occur, deteriorating the device characteristics of the piezoelectric element.
- An object of one aspect of the present invention is to provide a piezoelectric film capable of exhibiting excellent piezoelectric properties and reducing film stress.
- One aspect of the piezoelectric film according to the present invention comprises, as a main component, a piezoelectric material having a wurtzite crystal structure and an additive element containing Kr, the piezoelectric material comprising Zn, Al, Ga, Cd and One kind of component selected from the group consisting of Si is included as a positive element, and the ratio of the content of the Kr element to the content of the elements contained in the piezoelectric material is 0.01 atm % to 0.05 atm %.
- One aspect of the method for producing a piezoelectric film according to the present invention is the above-described method for producing a piezoelectric film, wherein the base material is formed by a sputtering method using a target containing Zn in a mixed gas atmosphere containing Kr and oxygen.
- the piezoelectric film is formed by sputtering the piezoelectric material while containing Kr thereon.
- electrodes and a piezoelectric layer are provided on a substrate, and the piezoelectric layer is the piezoelectric film described above.
- One aspect of the piezoelectric film according to the present invention can exhibit excellent piezoelectric characteristics and can reduce film stress.
- FIG. 1 is a schematic cross-sectional view showing the configuration of a piezoelectric film according to an embodiment of the present invention
- FIG. 4 is a schematic cross-sectional view showing an example of another configuration of a piezoelectric film
- FIG. It is a figure which shows an example of the relationship between a crystal orientation degree and an electromechanical coupling coefficient.
- 1 is a schematic cross-sectional view showing the configuration of a piezoelectric element provided with a piezoelectric film according to an embodiment of the invention
- FIG. FIG. 4 is a schematic cross-sectional view showing an example of another configuration of the piezoelectric element
- FIG. 4 is a schematic cross-sectional view showing an example of another configuration of the piezoelectric element
- FIG. 4 is a schematic cross-sectional view showing an example of another configuration of the piezoelectric element
- FIG. 4 is a schematic cross-sectional view showing an example of another configuration of the piezoelectric element
- FIG. 4 is a schematic cross-sectional view showing an example of another configuration of the piezoelectric element
- 3 is a diagram showing measurement results of axial ratio c/a of piezoelectric elements of Example 1 and Comparative Example 1.
- FIG. 1 is a schematic cross-sectional view showing the configuration of a piezoelectric film according to this embodiment.
- the piezoelectric film 10 according to the present embodiment contains a piezoelectric material having a wurtzite crystal structure (wurtzite crystal material) as a main component, and is composed of Ar, Kr, Xe, and Rn.
- wurtzite crystal material wurtzite crystal material
- Ar wurtzite crystal material
- Xe Xe
- Rn wurtzite crystal material
- One component selected from the group is included as an additive element.
- the piezoelectric film 10 can be used as a piezoelectric element, for example, by being provided on the substrate 11 .
- the thickness direction (vertical direction) of the piezoelectric film 10 is defined as the Z-axis direction
- the lateral direction (horizontal direction) orthogonal to the thickness direction is defined as the X-axis direction.
- the direction opposite to the substrate 11 side of the Z-axis direction is the +Z-axis direction
- the substrate 11 side is the ⁇ Z-axis direction.
- the +Z-axis direction is referred to as upward or upward
- the ⁇ Z-axis direction is referred to as downward or downward, but this does not represent a universal vertical relationship.
- the main component means that the content of the piezoelectric material is 95 atm% or more, preferably 98 atm% or more, more preferably 99 atm% or more.
- the base material 11 is a substrate on which the piezoelectric film 10 is installed. Any material can be used as the substrate 11, and a plastic substrate, a silicon (Si) substrate, a glass substrate, or the like can be used.
- a plastic base material When a plastic base material is used, it is preferable to use a flexible material that can give flexibility to the piezoelectric element including the piezoelectric film 10 .
- PET polyethylene terephthalate
- PEN polyethylene naphthalate
- PC polycarbonate
- acrylic resin cycloolefin polymer
- PI polyimide
- PET, PEN, PC, acrylic resins, and cycloolefin polymers are colorless and transparent materials, and are suitable when the electrodes used in the piezoelectric element having the piezoelectric film 10 are transparent electrodes.
- the material forming the plastic base material is the above-mentioned material.
- a translucent or opaque plastic material may be used.
- the thickness of the base material 11 is not particularly limited, and can be set to any appropriate thickness depending on the application of the piezoelectric film 10, the material of the base material 11, and the like.
- the thickness of the base material 11 may be 1 ⁇ m to 250 ⁇ m.
- a method for measuring the thickness of the base material 11 is not particularly limited, and any measuring method can be used.
- the piezoelectric film 10 contains a wurtzite crystal material as a main component.
- the wurtzite crystal structure of the piezoelectric material is represented by the general formula AB (A is a positive element and B is a negative element).
- a wurtzite crystal material has a hexagonal unit cell and a polarization vector in a direction parallel to the c-axis.
- the wurtzite crystal material it is preferable to use a material that exhibits piezoelectric properties of a certain value or more and can be crystallized by a low-temperature process of 200°C or less.
- the wurtzite crystal material contains, as a positive element A represented by the general formula AB, one component selected from the group consisting of Zn, Al, Ga, Cd and Si.
- wurtzite crystal materials examples include zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), aluminum nitride (AlN), gallium nitride (GaN), selenide Cadmium (CdSe), cadmium telluride (CdTe), silicon carbide (SiC), and the like can be used.
- ZnO is preferable as the wurtzite crystal material. These may be used individually by 1 type, and may be used together 2 or more types. When two or more wurtzite crystal materials are used in combination, one or more of these components may be included as the main component, and other components may be included as optional components.
- the wurtzite crystal material contains ZnO, preferably consists essentially of ZnO, and more preferably consists of ZnO only. “Substantially” means that, in addition to ZnO, unavoidable impurities that may be unavoidably included during the manufacturing process may be included.
- the respective piezoelectric films may be laminated.
- piezoelectric films 10A and 10B may be laminated on the substrate 11 in this order.
- Wurtzite type crystal materials include, in addition to ZnO, ZnS, ZnSe and ZnTe, alkaline earth metals such as Mg, Ca and Sr, vanadium (V), titanium (Ti), zirconium (Zr) and silica. Metals such as (Si) and lithium (Li) may be included in a predetermined range of proportions. These components may be contained in the form of elements or may be contained in the form of oxides. For example, if the wurtzite crystal material contains Mg in addition to ZnO or the like, the Mg can be contained as MgO. These components can distort the crystal lattice of ZnO by entering the Zn sites of ZnO and the like, so that the piezoelectric properties can be improved.
- the piezoelectric film 10 contains additive elements as described above.
- Ar, Kr, Xe, Rn, etc. can be used as the additive element. These may be used individually by 1 type, and may contain 2 or more types.
- the ratio of the content of the Kr element to the content of the contained element in the piezoelectric material is 0.01 atm% to 0.05 atm%, and 0.01 atm% to 0.04 atm % is preferred, and 0.01 atm % to 0.03 atm % is more preferred. If the content ratio of the Kr element is 0.01 atm % or more, the effect of the addition of the contained element can be exhibited, so that the c-axis orientation of the piezoelectric material can be enhanced and the increase in film stress can be suppressed.
- the content of the Kr element is 0.05 atm % or less, an increase in the oblique component of the sputtered particles reaching the substrate 11 can be suppressed under the sputtering film formation conditions, so that the crystal orientation of the piezoelectric material does not deteriorate. suppressed.
- the contained elements include all elements contained in the piezoelectric material.
- the contained element in the "content ratio of Kr element (Kr element/contained element)" means the total amount of contained elements.
- the contained element when the contained element is ZnO only, it means the content of ZnO only, and when the contained element contains Al 2 O 3 etc. in addition to ZnO, it means the content of ZnO, Al 2 O 3 etc. means total.
- Additive elements such as Kr contained in the piezoelectric film 10 and the contents of the contained elements are measured by, for example, Rutherford Backscattering Spectroscopy (RBS) using Pelletron 3SDH and 5SDH-2 (manufactured by NEC Corporation) as measuring devices.
- RBS Rutherford Backscattering Spectroscopy
- Pelletron 3SDH and 5SDH-2 manufactured by NEC Corporation
- the thickness of the piezoelectric film 10 is preferably 100 nm to 3000 nm, more preferably 200 nm to 2000 nm, even more preferably 300 nm to 1000 nm. If the thickness of the piezoelectric film 10 is 100 nm or more, when the piezoelectric film 10 is applied to a piezoelectric element, the piezoelectric film 10 is sufficiently thick even if an orientation control layer is provided below the piezoelectric film 10. piezoelectric properties, i.e., polarization properties proportional to pressure.
- the thickness of the piezoelectric film 10 is 3000 nm or less, even if the piezoelectric film 10 contains the additive element described above, the occurrence of cracks or the like in the piezoelectric film 10 can be reduced, and leakage paths between electrodes can be suppressed. , the piezoelectric film 10 can stably exhibit piezoelectric characteristics.
- the piezoelectric film 10 contains a wurtzite crystal material as a main component, and when the wurtzite crystal material contains Kr among Ar, Kr, Xe, and Rn as an additive element, the crystal orientation It is preferable that the degree is 5° or less and the film density is 5.1 g/cm 3 or less.
- the wurtzite crystal material may consist essentially of ZnO, or may consist of ZnO only.
- the piezoelectric film 10 is mainly composed of a wurtzite crystal material containing ZnO. , an increase in film stress is suppressed.
- the degree of crystal orientation is preferably 5° or less, more preferably 2.8° or less, and even more preferably 2.5° or less. If the degree of crystal orientation is 5° or less, the c-axis orientation of the piezoelectric material contained in the piezoelectric film 10 is good, and the energy conversion efficiency can be improved, so that the piezoelectric properties of the piezoelectric film 10 can be improved.
- ZnO has a wurtzite crystal structure, and has a higher correlation between the degree of crystal orientation and piezoelectric properties than piezoelectric materials having other crystal structures. Therefore, if the degree of crystal orientation of ZnO is 5° or less, the energy conversion efficiency can be easily increased. Therefore, when the piezoelectric film 10 is applied to a piezoelectric element, the piezoelectric characteristics of the piezoelectric element can be improved.
- the degree of crystal orientation is indicated by the full width at half maximum (FWHM) obtained when the surface of the piezoelectric film 10 is measured by an X-ray rocking curve (XRC) method. That is, the degree of crystal orientation is expressed by the FWHM of the peak waveform of the rocking curve obtained by measuring the reflection from the (0002) plane of the ZnO crystal, which is the main component of the piezoelectric film 10, by the XRC method.
- the FWHM indicates the degree of parallelism in the c-axis direction arrangement of the crystals forming the piezoelectric material.
- the FWHM of the peak waveform of the rocking curve obtained by the XRC method serves as an index of the c-axis orientation of the piezoelectric film 10 . Therefore, it can be evaluated that the smaller the FWHM of the rocking curve, the better the crystal orientation of the piezoelectric film 10 in the c-axis direction.
- FIG. 3 shows an example of the relationship between the degree of crystal orientation and the electromechanical coupling coefficient K.
- FIG. 3 shows the relationship between the degree of crystal orientation of AlN and the electromechanical coupling coefficient K.
- the horizontal axis is the degree of crystal orientation
- the vertical axis is the square value of the electromechanical coupling constant K ( K2 value).
- FIG. 3 shows the relationship between the crystal orientation and the electromechanical coupling coefficient in the case of AlN, the crystal orientation and the electromechanical coupling coefficient of ZnO, ZnO—MgO, etc. are similar to those of AlN. Show relationship.
- the K 2 value on the vertical axis indicates the energy conversion efficiency of electrical energy determined for the piezoelectric film 10 .
- FIG. 3 shows the relationship between the degree of crystal orientation and the electromechanical coupling coefficient in the case of AlN. A similar relationship is shown with the mechanical coupling coefficient. Therefore, in the present embodiment, the crystal orientation is considered to be good when the degree of crystal orientation is 5° or less at which the piezoelectricity begins to saturate while improving the energy conversion efficiency.
- the film density is preferably 5.1 g/cm 3 or less, more preferably 4.96 g/cm 3 or less, even more preferably 4.94 g/cm 3 or less. Note that the lower limit of the film density is determined as appropriate. If the film density is 5.1 g/cm 3 or less, the elements constituting the piezoelectric film 10 can be prevented from becoming dense, and can be in a so-called sparse state. The generation of stress in the piezoelectric film 10 can be suppressed, and an increase in the film stress of the piezoelectric film 10 can be suppressed. Therefore, when the piezoelectric film 10 is applied to a piezoelectric element, deterioration of the piezoelectric characteristics of the piezoelectric element can be prevented.
- the method for measuring the film density is not particularly limited, and for example, X-ray reflectometry (XRR) or the like can be used.
- XRR X-ray reflectometry
- the crystal orientation of the piezoelectric film 10 is the peak intensity of the rocking curve obtained by measuring the reflection from the (0002) plane of the ZnO crystal contained as the piezoelectric material in the piezoelectric film 10 by the X-ray rocking curve method. and FWHM.
- a value obtained by dividing the integrated value of the peak intensity by FWHM can be used as an evaluation value of the degree of crystal orientation.
- the stronger the peak intensity of the rocking curve and the smaller the FWHM the better the c-axis orientation of ZnO. Therefore, the larger the evaluation value obtained by dividing the integrated value of the peak intensity by the FWHM, the better the crystal orientation (that is, the lower the degree of crystal orientation).
- the piezoelectric film 10 contains a wurtzite crystal material as a main component, and when the wurtzite crystal material contains Kr among Ar, Kr, Xe, and Rn as an additive element, the piezoelectric material
- the axial ratio c/a of the crystal structure contained in is preferably 1.59 or less, more preferably 1.585 or less, and even more preferably 1.582 or less.
- a wurtzite crystal material such as ZnO has a hexagonal crystal system, and is randomly oriented along the a-axis in the in-plane direction of the unit cell of the wurtzite crystal material.
- a wurtzite crystal material such as ZnO extends along the a-axis in the in-plane direction. If the axial ratio c/a is within the above preferable range, the piezoelectric material can have a uniform stress distribution in the crystal plane, so that the increase in film stress is suppressed while maintaining the c-axis orientation.
- the lower limit of the axial ratio c/a is not particularly limited, but is preferably 1.560 or more.
- the axial ratio c/a of the crystal structure contained in the piezoelectric material is the ratio (c-axis/a-axis ratio).
- the axial ratio c/a can be controlled by controlling the amount of other elements doped into ZnO, lattice matching with the underlying material, and the temperature and pressure during formation of the piezoelectric material.
- the axial ratio c/a of the crystal structure of the piezoelectric material can be evaluated by an in-plane X-ray diffraction method at room temperature.
- the evaluation method of the film stress of the piezoelectric film 10 is not particularly limited as long as the film stress of the piezoelectric film 10 can be evaluated, and various measurement methods can be used for evaluation.
- the film stress of the piezoelectric film 10 can be evaluated from, for example, the amount of warpage.
- the amount of warpage of the piezoelectric film 10 is measured when the piezoelectric film 10 is placed on the substrate 11 and the installation surface of the piezoelectric film 10 is placed downward, and the installation surface of the piezoelectric film 10 is in contact with the substrate 11.
- the amount of warpage of the piezoelectric film 10 can be obtained by calculating the average value of the heights in the direction perpendicular to the corners of the piezoelectric film 10 and the surface where the piezoelectric film 10 is bent.
- the average height of the four corners of the piezoelectric film 10 and the surface of the piezoelectric film 10 on which the substrate 11 is placed is taken as the average height of the piezoelectric film 10. It is the amount of warpage of the film 10 .
- the amount of warpage is equal to or less than a predetermined value (for example, 10 mm), it can be evaluated that the amount of warpage of the piezoelectric film 10 is good.
- the piezoelectric film 10 is formed by sputtering a piezoelectric material containing ZnO while containing Kr on the substrate 11 by a sputtering method using a target containing Zn such as ZnO in a mixed gas atmosphere containing Kr and oxygen. Film can be formed. As will be described later, in addition to Kr, Ar or the like may be used as the mixed gas atmosphere containing oxygen. It can be said that the piezoelectric film develops compressive stress by entering into the film, which is a factor in increasing the film stress.
- the piezoelectric film 10 When the mixed gas atmosphere contains Kr, Kr atoms enter into the crystal lattice of the piezoelectric material, but are more difficult to enter into the crystal lattice of the wurtzite crystal material than Ar atoms, and compressive stress is applied to the piezoelectric film 10 . You can suppress the expression. Therefore, by forming the piezoelectric film 10 by sputtering in a mixed gas atmosphere containing Kr and oxygen, the piezoelectric film 10 can be formed while suppressing an increase in the film stress.
- the ratio of the flow rate of oxygen to the total flow rate of Kr and oxygen is preferably 5% to 15%, more preferably 7% to 12%. If the ratio of the flow rate of oxygen to the total flow rate of Kr and oxygen is within the above preferable range, when the piezoelectric film 10 is formed by sputtering using a target containing Zn, Kr atoms are urtzites such as ZnO. Even if Kr enters the crystal lattice of the ore-type crystal material, the amount of Kr that enters can be suppressed. Therefore, an increase in the film stress of the piezoelectric film 10 can be suppressed while maintaining the high c-axis orientation of the piezoelectric material.
- the pressure in the mixed gas atmosphere during sputtering is preferably 0.1 Pa to 2.0 Pa, more preferably 0.5 Pa to 1.5 Pa. If the pressure is within the above preferred range, when the piezoelectric film 10 is formed by a sputtering method using a target containing Zn, Kr atoms enter the crystal lattice of the wurtzite crystal material such as ZnO. can reduce the amount of Therefore, an increase in the film stress of the piezoelectric film 10 can be suppressed while maintaining the high c-axis orientation of the piezoelectric material.
- a ZnO sintered compact target can be used as the target.
- a ZnO sintered body target is placed in a sputtering apparatus, and a mixed gas containing Kr and oxygen is supplied into the sputtering apparatus.
- the piezoelectric film 10 is obtained on the substrate 11 while suppressing the amount of Kr entering during the formation of the ZnO film. be able to.
- the wurtzite crystal material is a Mg-added ZnO thin film containing ZnO and MgO at a predetermined mass ratio
- a multi-source sputtering method using a target made of a ZnO sintered body and a target made of a MgO sintered body, or in advance A one-dimensional sputtering method using an alloy target containing ZnO and MgO, such as a ZnO sintered body target to which MgO is added at a predetermined ratio, can be used.
- a multi-source sputtering device When using the multi-source sputtering method, a multi-source sputtering device is used to supply a mixed gas containing Kr and oxygen into the multi-source sputtering device.
- a ZnO sintered body target and a MgO sintered body target are simultaneously and independently sputtered onto the base material 11 to form Mg-added ZnO on the base material 11. It is possible to form a Mg-added ZnO thin film while suppressing the amount of Kr entering during thin film deposition and suppressing the Kr content within a desired range.
- the piezoelectric film 10 composed of the Mg-added ZnO thin film having a Kr content of 0.01 atm % or more is obtained.
- the Mg-added ZnO thin film can be formed so that Kr is contained in a desired ratio.
- the piezoelectric film 10 containing the desired amount of Kr in the Mg-added ZnO thin film is obtained.
- the piezoelectric film 10 is mainly composed of a piezoelectric material having a wurtzite crystal structure, and contains Kr as an additive element.
- the piezoelectric film 10 contains, as a positive element, one kind of component selected from the group consisting of Zn, Al, Ga, Cd and Si in the piezoelectric material, and the content ratio of the Kr element is 0.01 atm % to 0.01 atm %. 05 atm %.
- the piezoelectric film 10 can have enhanced c-axis orientation and high crystal orientation.
- the piezoelectric film 10 can obtain a large displacement in the thickness direction.
- the piezoelectric film 10 can suppress an increase in film stress by suppressing the content ratio of the Kr element contained in the piezoelectric material to the above-mentioned content. Therefore, the piezoelectric film 10 can have a large displacement in the thickness direction and can suppress an increase in film stress, so that excellent piezoelectric characteristics can be exhibited and film stress can be reduced. can be done. Therefore, by using the piezoelectric film 10 in a piezoelectric element, the piezoelectric characteristics of the piezoelectric element can be improved.
- Kr atoms are a rare gas having a larger atomic weight and atomic radius than Ar atoms, they are more difficult to enter than Ar when the piezoelectric film 10 is formed. can be significantly reduced compared to the case of Therefore, even if the piezoelectric film 10 contains Kr atoms, the content thereof is much smaller than that of Ar, so that the film stress of the piezoelectric film 10 can be reduced.
- the recoil component of the Kr atoms is small, and the oblique component of the sputtered particles reaching the substrate 11 can be reduced compared to the Ar atoms, so that the crystal orientation can be improved.
- the piezoelectric element can be excellent without providing an orientation control layer or an intermediate layer for stress relaxation between the lower electrode and the piezoelectric layer. Since it can have piezoelectric properties and low film stress, it can reliably exhibit excellent piezoelectric properties over a long period of time.
- the piezoelectric film 10 has a piezoelectric material containing ZnO, and can have a crystal orientation of 5° or less and a film density of 5.1 g/cm 3 or less. As a result, the piezoelectric film 10 can improve the c-axis orientation of the piezoelectric material, have a high crystal orientation, and can suppress an increase in film stress. Therefore, the piezoelectric film 10 can have a large displacement in the thickness direction and can suppress an increase in film stress, so that excellent piezoelectric characteristics can be exhibited and film stress can be reduced. can be done.
- the piezoelectric film 10 has a piezoelectric material containing ZnO, and the crystal structure contained in the piezoelectric material has an axial ratio c/a of 1.59 or less.
- the piezoelectric material can extend the a-axis length of the unit cell by including an additive element such as Kr.
- the piezoelectric material such as ZnO can have a uniform stress distribution within the crystal plane. , the compressive stress can be reduced. Therefore, the piezoelectric film 10 can further reduce the film stress.
- the piezoelectric film 10 can have a thickness of 100 nm to 3000 nm. As a result, the piezoelectric film 10 can exhibit excellent piezoelectric characteristics and reduce film stress while being made thinner.
- the piezoelectric film 10 has the characteristics described above, it can be suitably used as a piezoelectric layer of a piezoelectric element.
- the piezoelectric element according to this embodiment includes electrodes and a piezoelectric layer on a substrate, and the piezoelectric film 10 according to this embodiment shown in FIG. 1 is used for the piezoelectric layer.
- FIG. 4 is a schematic cross-sectional view showing the configuration of the piezoelectric element.
- the piezoelectric element 20A includes an orientation control layer 22, a first electrode 23, a piezoelectric layer 24, and a second electrode 25 laminated in this order on a substrate 21.
- FIG. The piezoelectric layer 24 is composed of the piezoelectric film 10 according to this embodiment shown in FIG. Note that the piezoelectric element 20A may not include at least one of the orientation control layer 22 and the second electrode 25 depending on the application.
- the base material 21 can be the base material 11 on which the piezoelectric film 10 according to the present embodiment shown in FIG. 1 is installed, so the details of the base material 21 are omitted.
- the arrangement position of the base material 21 is not particularly limited, and it can be arranged in an appropriate position according to the structure of the piezoelectric element 20A, the manufacturing process, etc.
- the base material 21 is It may be arranged between the orientation control layer 22 and the first electrode 23 .
- the orientation control layer 22 can be provided between the substrate 21 and the first electrode 23 .
- the orientation control layer 22 has the function of adjusting the consistency of crystal growth between the substrate 21 and the piezoelectric layer 24 adjacent in the stacking direction, and forming the piezoelectric layer 24 by crystal growth close to epitaxial growth. . Therefore, the piezoelectric layer 24 formed above the first electrode 23 can have good c-axis orientation even if its thickness is, for example, several hundred nm.
- the orientation control layer 22 has excellent surface smoothness and has the function of improving the c-axis orientation of the piezoelectric layer 24 located above.
- the piezoelectric layer 24 contains ZnO
- the c-axis of the piezoelectric layer 24 can be oriented in the vertical direction (stacking direction).
- the orientation control layer 22 has a high gas barrier property, and when a plastic base material is used as the base material 21, the effect of gas generated from the plastic base material during film formation can be reduced.
- the orientation control layer 22 is formed using a thermosetting resin, the orientation control layer 22 is amorphous and highly smooth.
- the alignment control layer 22 is formed using a melamine resin, the alignment control layer 22 has a three-dimensional crosslinked structure, so that the density in the layer can be increased and the barrier properties can be improved.
- the orientation control layer 22 preferably contains an amorphous material.
- the orientation control layer 22 does not necessarily have to be 100% amorphous, and may have non-amorphous regions as long as the c-axis orientation of the piezoelectric layer 24 can be enhanced. If the proportion of the region formed of the amorphous component in the region of the orientation control layer 22 is preferably 90% or more, more preferably 95% or more, a sufficient c-axis orientation control effect can be obtained. .
- the orientation control layer 22 can be formed from an inorganic substance, an organic substance, or a mixture of an inorganic substance and an organic substance.
- Materials used for the inorganic substance, the organic substance, and the mixture are not particularly limited as long as they improve the wettability between the substrate 21 and the first electrode 23 and improve the crystal orientation of the first electrode 23 .
- Inorganic substances include silicon oxide (SiOx), silicon nitride (SiN), aluminum nitride (AlN), aluminum oxide ( Al2O3 ), gallium nitride (GaN) , gallium oxide ( Ga2O3 ); Al2O3 . and SiOx doped ZnO ( aluminum/silicon - added zinc oxide ( hereinafter referred to as " SAZO "));ZnO; ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IZTO (Indium Zinc Tin Oxide), IGZO (Indium Gallium Zinc Oxide) and the like can be used.
- Organic substances include organic substances such as acrylic resins, urethane resins, melamine resins, alkyd resins, and siloxane polymers.
- a thermosetting resin comprising a mixture of a melamine resin, an alkyd resin and an organic silane condensate as the organic material.
- an amorphous film can be formed by a vacuum deposition method, a sputtering method (sputtering method), an ion plating method, a coating method, or the like.
- the orientation control layer 22 may be a single layer or a laminate of two or more layers. When the orientation control layer 22 is formed by laminating two or more layers, an inorganic thin film and an organic thin film may be laminated.
- the thickness of the orientation control layer 22 can be appropriately designed, and is preferably 3 nm to 100 nm, more preferably 10 nm to 50 nm, for example. If the thickness of the orientation control layer 22 is within the above preferable range, the orientation controllability can be exhibited and the thickness of the piezoelectric element can be reduced. Therefore, the crystal orientation of the piezoelectric layer 24 positioned above can be sufficiently improved, and the crystallinity of the piezoelectric layer 24 can be improved.
- the first electrode 23 is provided on the orientation control layer 22 . Any conductive material can be used for the first electrode 23 . When light transmittance is required, a transparent conductive oxide film such as ITO, IZO, IZTO, or IGZO can be used as the material. If transparency is not essential, good conductors such as metals such as Au, Pt, Ag, Ti, Al, Mo, Ru, Cu, and W may be used.
- the oxide conductor film may be an amorphous film.
- an amorphous film it is possible to suppress unevenness on the surface of the first electrode 23 and generation of crystal grain boundaries that cause leakage paths.
- the upper piezoelectric layer 24 can be grown with good crystal orientation without being affected by the crystal orientation of the first electrode 23 .
- the first electrode 23 may be formed in the form of a thin film on part or the entire surface of the orientation control layer 22, or may be provided in parallel in a plurality of stripes.
- the second electrode 25 can be provided on the piezoelectric layer 24 .
- the second electrode 25 can be made of any conductive material. If the piezoelectric element 20A requires optical transparency, it may be made of a transparent oxide conductive film such as ITO, IZO, IZTO, or IGZO. If light transmittance is not essential, metal electrodes of good conductors such as Au, Pt, Ag, Ti, Al, Mo, Ru, Cu, and W may be used.
- the second electrode 25 may be formed in the form of a thin film on a part or the entire surface of the piezoelectric layer 24, or may be provided in parallel in a stripe shape.
- the orientation control layer 22 is formed on the surface of the base material 21 .
- An IZO film or the like can be used as the orientation control layer 22 .
- a method for forming the orientation control layer 22 for example, a sputtering method at room temperature can be used.
- the film formation temperature of the orientation control layer 22 does not have to be room temperature as long as the amorphous structure can be maintained.
- a first electrode 23 is formed above the orientation control layer 22 .
- the first electrode 23 for example, an ITO film, a Ti film, or the like formed by a DC (direct current) or RF (radio frequency) magnetron sputtering method can be used.
- the first electrode 23 may be used as a solid electrode, or the first electrode 23 may be processed into a predetermined pattern by etching or the like.
- a plurality of first electrodes 23 may be arranged in stripes.
- a piezoelectric layer 24 is formed on the first electrode 23 .
- the film is formed by RF magnetron sputtering in a mixed gas atmosphere containing Kr and a small amount of oxygen.
- the ratio of the oxygen flow rate to the total flow rate of Kr and oxygen is preferably 5% to 15%, and the pressure in the mixed gas atmosphere during sputtering is preferably 0.1 Pa to 2.0 Pa.
- the piezoelectric layer 24 containing ZnO and MgO while suppressing the amount of Kr entering the crystal structure of ZnO and MgO, and having a Kr content of 0.01 atm % to 0.05 atm %.
- the piezoelectric layer 24 may be formed by sputtering in a mixed gas atmosphere containing Kr and a small amount of oxygen using an MgZnO target containing Zn with a predetermined proportion of Mg.
- a ZnO target and an MgO target may be simultaneously and independently sputtered in a mixed gas atmosphere containing Kr and a small amount of oxygen using a multi-source sputtering apparatus.
- the piezoelectric layer 24 may be configured by laminating a plurality of layers.
- the film forming temperature of the piezoelectric layer 24 does not have to be room temperature as long as the amorphous structure of the orientation control layer 22 located below the piezoelectric layer 24 is maintained.
- the piezoelectric layer 24 may be deposited at a substrate temperature of 150° C. or less.
- the orientation control layer 22, the first electrode 23, and the piezoelectric layer 24 By using the sputtering method to form the orientation control layer 22, the first electrode 23, and the piezoelectric layer 24, it is possible to form a uniform film with strong adhesion while maintaining the composition ratio of the compound target. Further, the orientation control layer 22, the first electrode 23, and the piezoelectric layer 24 having desired thicknesses can be accurately formed only by controlling the time.
- a second electrode 25 having a predetermined shape is formed on the piezoelectric layer 24 .
- an ITO film having a thickness of 20 nm to 100 nm is formed at room temperature by, for example, a DC or RF magnetron sputtering method.
- the second electrode 25 may be formed on the entire surface of the piezoelectric layer 24, or may be formed in any suitable shape.
- the second electrode 25 has a plurality of stripes extending in a direction orthogonal to the direction in which the stripes of the first electrode 23 extend in plan view. may be formed so as to extend.
- the entire piezoelectric element 20A may be heat-treated at a temperature lower than the melting point or glass transition point of the base material 21 (for example, 130°C). By this heat treatment, the first electrode 23 and the second electrode 25 can be crystallized and have low resistance.
- the heat treatment is not essential, and may not be performed after the piezoelectric element 20A is formed, for example, when the base material 21 is made of a non-heat-resistant material.
- the piezoelectric element 20A includes the piezoelectric layer 24 between the first electrode 23 and the second electrode 25, and the piezoelectric layer 24 exhibits excellent piezoelectric characteristics and can reduce film stress.
- the piezoelectric element 20A can exhibit high piezoelectric efficiency in the thickness direction of the piezoelectric layer 24, and can reliably exhibit excellent piezoelectric characteristics.
- the piezoelectric characteristics of the piezoelectric element 20A can be evaluated by the d33 value.
- the d33 value is a value representing the expansion/contraction mode of the piezoelectric layer 24 in the thickness direction, and is the polarization charge amount [C/N] per unit pressure applied to the piezoelectric layer 24 in the thickness direction. Note that the d33 value is also called a piezoelectric constant. The higher the d33 value, the better the polarization in the thickness direction (c-axis direction) of the piezoelectric layer 24 of the piezoelectric element 20A.
- the d 33 value can be directly measured using a piezoelectric constant measuring device (LPF-02, manufactured by Lead Techno Co., Ltd.) or the like.
- the upper and lower surfaces of the piezoelectric layer 24 are sandwiched between electrodes of a piezoelectric constant measuring device, an indenter is pressed against the surface of the piezoelectric layer 24, a load is applied to the piezoelectric layer 24 at a low frequency, and the amount of charge generated is measured as a piezoelectric value.
- a value obtained by dividing the measured amount of charge by the weight is output as the d33 value.
- the larger the absolute value of the d33 value the better the piezoelectric properties of the piezoelectric layer 24 in the film thickness direction.
- piezoelectric element 20A Since the piezoelectric element 20A has excellent piezoelectric characteristics, it can be suitably used as a piezoelectric device.
- Piezoelectric devices include, for example, force sensors for touch panels, pressure sensors, acceleration sensors, acoustic emission (AE) sensors, and other devices using the piezoelectric effect; speakers, transducers, high-frequency filter devices, and piezoelectric actuators using the inverse piezoelectric effect. , an optical scanner, and the like.
- the piezoelectric element 20A is not limited to the above configuration, and has the first electrode 23 and the piezoelectric layer 24 on the base material 21, and the piezoelectric layer 24 extends in the thickness direction. Other configurations may be used as long as they can exhibit excellent piezoelectric characteristics. An example of another configuration of the piezoelectric element 20A is shown below.
- the piezoelectric element 20B may not have the second electrode 25.
- the piezoelectric element 20C does not have to include the orientation control layer 22.
- the piezoelectric element 20D may include an orientation control layer 22 between the first electrode 23 and the piezoelectric layer 24.
- the piezoelectric element 20E may include an adhesive layer 26 between the piezoelectric layer 24 and the second electrode 25 and a substrate 27 on the upper surface of the second electrode 25.
- the adhesive layer 26 suppresses leak paths caused by cracks and pinholes that occur in the piezoelectric layer 24 . If metal grain boundaries or projections exist at the interface between the first electrode 23 and the piezoelectric layer 24 or at the interface between the piezoelectric layer 24 and the second electrode 25, the first electrode 23, the piezoelectric layer 24 and the second When a crack or the like occurs in one of the electrodes 25, a leak path is formed between the first electrode 23 and the second electrode 25 due to the crack or the like, and the polarization disappears.
- the piezoelectric element 20 ⁇ /b>E has the adhesive layer 26 between the piezoelectric layer 24 and the second electrode 25 , thereby suppressing the formation of leak paths and maintaining good piezoelectric characteristics of the piezoelectric layer 24 .
- a material similar to that of the base material 21 can be used for the base material 27 .
- the orientation control layer 22, the first electrode 23, and the piezoelectric layer 24 are laminated in this order on the substrate 21 to form a first laminate.
- a second laminate is formed by forming the second electrode 25 on the substrate 27 .
- the piezoelectric layer 24 and the second electrode 25 of the second laminate are bonded together via the adhesive layer 26 so that the piezoelectric layer 24 of the first laminate and the second electrode 25 of the second laminate face each other. .
- the piezoelectric element 20E is manufactured.
- the piezoelectric element 20E has a large electromechanical coupling coefficient in the thickness vibration mode and can suppress leak paths between electrodes, so that it can have better piezoelectric characteristics.
- Example 1 (Production of orientation control layer) An amorphous IZO film was formed to a thickness of 50 nm on a substrate (PET, thickness: 50 ⁇ m) using a DC sputtering method in a mixed gas atmosphere of Ar and O 2 . .
- a hexagonal wurtzite was deposited using a DC sputtering method using a sputtering target in which ZnO and MgO were adjusted to a mass ratio of 88 wt%: 12 wt%.
- a Mg-added ZnO thin film having a type structure was formed with a thickness of 30 nm.
- a Mg-added ZnO thin film was formed on the IZO film.
- the total thickness of the orientation control layer was 80 nm.
- a 30 nm-thick Ti film which is a hexagonal metal layer, was formed as a first electrode in a mixed gas atmosphere of Ar and O 2 using a DC magnetron sputtering method.
- the gas pressure was adjusted to 0.7 Pa in a mixed gas atmosphere of Kr and O2 , and the mass ratio of ZnO and MgO was adjusted to 88 wt%: 12 wt% using a DC sputtering method.
- a Mg-added ZnO thin film having a hexagonal wurtzite structure was formed as a piezoelectric layer.
- the thickness of the piezoelectric layer was set to 500 nm.
- a piezoelectric element was produced that had the orientation control layer, the first electrode, and the piezoelectric layer laminated in this order on the substrate.
- the Kr content ratio (Kr element/content element) in the prepared sample was measured using Pelletron 3SDH and 5SDH-2 (manufactured by NEC Corporation) using Rutherford backscattering spectrometry (RBS) under the following measurement conditions and evaluation. Based on the standard, the Kr content contained in the piezoelectric layer was evaluated. In addition, a contained element means ZnO and MgO. The detection lower limit of the Kr content in the piezoelectric layer of the sample was 0.01 atm %.
- film density The film density of the prepared sample was measured by the X-ray reflectance measurement method using an X-ray diffractometer (SmartLab, manufactured by Rigaku Corporation) under the following measurement conditions to determine the film density of the piezoelectric layer.
- (Measurement condition) ⁇ Measuring range: 0.2° to 8.0° ⁇ Measurement interval: 0.01° ⁇ Speed/counting time: 0.5°/min ⁇ Divergence slit: 0.05 mm
- the prepared sample was cut into a 3 cm square, placed on a reference surface with the surface on which the piezoelectric layer was formed facing downward, and the average height in the vertical direction between the reference surface and each of the four corners of the sample was calculated. By calculating, the amount of warpage of the piezoelectric layer was obtained. When the warp amount was 10 mm or less, the film warp was evaluated as good.
- piezoelectric characteristics A piezoelectric element is placed on the stage, the first electrode is pulled out on the stage, and an indenter positioned above the piezoelectric element is applied with a set pressure to generate lattice distortion in the piezoelectric layer. The charge generated by the polarization in the film thickness direction was evaluated. The pressure difference from the initial pressure was varied from 1N to 9N, and the value obtained by dividing the generated charge amount by the applied pressure was calculated and evaluated as piezoelectric characteristics.
- Piezoelectric properties were evaluated by the d33 value.
- the d 33 value of the piezoelectric layer was directly measured using a piezometer PM300 (manufactured by Piezotest).
- the d33 value is a value representing the expansion/contraction mode of the piezoelectric element in the thickness direction, and is the polarization charge amount [C/N] per unit pressure applied in the thickness direction.
- the higher the d33 value the better the polarization in the thickness direction (c-axis direction) of the piezoelectric layer, and the higher the piezoelectric characteristics of the piezoelectric element.
- Table 1 shows the measurement results of the d 33 value, which is the piezoelectric characteristic of the piezoelectric element.
- the obtained piezoelectric layer had a degree of crystal orientation of 2.5° even with a thickness of 500 nm, which is 5° or less at which the energy conversion efficiency of the piezoelectric element can be enhanced. , it can be said that the crystal orientation is good.
- the film density was 4.94 g/cm 3 , which was 5.1 g/cm 3 or less at which the film stress of the piezoelectric layer increases, so it can be said that the film density is good.
- the axial ratio c/a was 1.582, which was 1.590 or less, the lattice constant of the crystal of the main component constituting the piezoelectric layer was such that the length of the a-axis was greater than the length of the c-axis. It can be said that the axial ratio c/a is good because the stress of the crystal plane is easily made uniform in the direction parallel to the base material.
- the piezoelectric characteristic d 33 value indicating the piezoelectricity of the piezoelectric material was 12.7 pC/N. Further, since the amount of warpage of the piezoelectric layer was 4.5 mm, it can be said that the warpage of the piezoelectric layer is kept low. Therefore, it was confirmed that suppression of the film stress of the piezoelectric layer and good crystal orientation are compatible.
- Example 2 A piezoelectric element was produced in the same manner as in Example 1, except that the thickness of the piezoelectric layer was changed to 1000 nm. Content ratio of Kr element in the piezoelectric layer, thickness, degree of crystal orientation, film density, axial ratio c/a and amount of warpage of the piezoelectric layer, and measurement results of piezoelectric characteristics ( d33 value) of the piezoelectric element are shown in Table 1.
- the obtained piezoelectric layer had a FWHM of 2.4° even when the thickness was 1000 nm, which was 5° or less at which the energy conversion efficiency of the piezoelectric element was improved. It can be said that the properties are good.
- the piezoelectric characteristic d 33 value indicating the piezoelectricity of the piezoelectric material was 11.2 pC/N. Further, since the amount of warping of the piezoelectric layer was 6.1 mm, it can be said that the warping of the piezoelectric layer is kept low. Therefore, it was confirmed that even with a piezoelectric element having a piezoelectric layer of 1000 nm, both suppression of film stress in the piezoelectric layer and good crystal orientation are achieved.
- Example 3 A piezoelectric element was fabricated in the same manner as in Example 1, except that the film-forming gas pressure of the piezoelectric layer was changed from 0.7 Pa to 1.6 Pa. Content ratio of Kr element in the piezoelectric layer, thickness, degree of crystal orientation, film density, axial ratio c/a and amount of warpage of the piezoelectric layer, and measurement results of piezoelectric characteristics ( d33 value) of the piezoelectric element are shown in Table 1.
- the resulting piezoelectric layer had a FWHM of 3.6° even when the film-forming gas pressure was 1.6 Pa. Therefore, it can be said that the degree of crystal orientation is good.
- the piezoelectric characteristic d 33 value indicating the piezoelectricity of the piezoelectric material was 9.2 pC/N. Further, since the amount of warpage of the piezoelectric layer was 3.8 mm, it can be said that the warpage of the piezoelectric layer is kept low. Therefore, it was confirmed that even with a piezoelectric layer formed at a film-forming gas pressure of 1.6 Pa, both suppression of film stress and good crystal orientation were achieved.
- Example 1 A piezoelectric element was produced in the same manner as in Example 1, except that the production of the piezoelectric layer was changed as follows. (Production of piezoelectric layer) On the first electrode, the gas pressure was adjusted to 0.2 Pa in a mixed gas atmosphere of Ar and O2 , and the mass ratio of ZnO and MgO was 88 wt%: 12 wt% using a DC sputtering method. An adjusted Mg-added ZnO thin film having a hexagonal wurtzite structure was deposited as a piezoelectric layer.
- FIG. 9 shows the measurement results of the axial ratio c/a.
- the obtained piezoelectric layer had a FWHM of 2.5° even when the thickness was 500 nm, which was 5° or less at which the energy conversion efficiency of the piezoelectric element was improved. It was confirmed that the crystal orientation of the piezoelectric layer was good.
- the lattice constant of the crystal of the main component constituting the piezoelectric layer is such that the length of the a-axis is longer than the length of the c-axis. It was confirmed that the axial ratio c/a was unsatisfactory because it was formed rather short and it was difficult to uniformize the stress of the crystal plane in the direction parallel to the base material.
- the piezoelectric characteristic d 33 value indicating the piezoelectricity of the piezoelectric material was 11.8 pC/N.
- the amount of warpage of the piezoelectric layer when the sample was placed on a reference surface with the surface on which the piezoelectric layer was formed facing downward, the sample became cylindrical and the film stress was extremely large, making it impossible to measure. and
- the piezoelectric characteristic d 33 value indicating the piezoelectricity of the piezoelectric material was 10.5 pC/N.
- the amount of warpage of the piezoelectric layer when the sample was placed on a reference surface with the surface on which the piezoelectric layer was formed facing downward, the sample became cylindrical and the film stress was extremely large, making it impossible to measure. did.
- Comparative Example 3 A piezoelectric element was fabricated in the same manner as in Comparative Example 1, except that the gas pressure was changed from 0.2 Pa to 3.0 Pa when fabricating the piezoelectric layer.
- the lattice constant of the crystal of the main component constituting the piezoelectric layer is such that the length of the a-axis is longer than the length of the c-axis. It was confirmed that the axial ratio c/a was unsatisfactory because it was formed rather short and it was difficult to uniformize the stress of the crystal plane in the direction parallel to the base material.
- the piezoelectric characteristic d 33 value indicating the piezoelectricity of the piezoelectric material was 6.5 pC/N.
- the amount of warpage of the piezoelectric layer was 22.4 mm, exceeding 10 mm, so it was confirmed that the film stress was large and defective.
- Example 4 A piezoelectric element was fabricated in the same manner as in Example 1, except that the gas pressure was changed from 0.7 Pa to 0.2 Pa when fabricating the piezoelectric layer.
- the piezoelectric characteristic d 33 value indicating the piezoelectricity of the piezoelectric material was 12.1 pC/N.
- the Kr content in the piezoelectric layer is less than the detection limit of 0.01 atm %, the amount of warpage of the piezoelectric layer is large and cannot be suppressed.
- the reason for this is as follows. In general, when the gas pressure is low, the amount of Ar atoms present is small, so the amount of Ar atoms taken into the piezoelectric layer is small, and the film density tends to be high, resulting in a strong compressive stress. Similarly, in the case of Kr gas, in the region where the gas pressure is low, the amount of incorporated sputtering gas atoms is small, and the film density tends to be high.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Metallurgy (AREA)
- Crystallography & Structural Chemistry (AREA)
- Structural Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Mechanical Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Physical Vapour Deposition (AREA)
Abstract
Description
本発明の実施形態に係る圧電体膜について説明する。図1は、本実施形態に係る圧電体膜の構成を示す概略断面図である。図1に示すように、本実施形態に係る圧電体膜10は、ウルツ鉱型の結晶構造を有する圧電材料(ウルツ鉱型結晶材料)を主成分として含み、Ar、Kr、Xe及びRnからなる群より選択される一種の成分を添加元素として含む。圧電体膜10は、例えば、基材11上に設けられることで、圧電素子に使用できる。
本実施形態に係る圧電体を備えた圧電素子について説明する。本実施形態に係る圧電素子は、基板上に、電極及び圧電体層を備え、圧電体層に、図1に示す本実施形態に係る圧電体膜10が用いられる。
なお、本実施形態においては、圧電素子20Aは、上記構成に限定されず、基材21の上に、第1の電極23と、圧電体層24を有し、圧電体層24が厚さ方向に優れた圧電特性を発揮することができれば、他の構成でもよい。圧電素子20Aの他の構成の一例を以下に示す。
[実施例1]
(配向制御層の作製)
基材(PET、厚さ:50μm)上に、ArとO2の混合ガス雰囲気中で、DCスパッタリング法を用いて、非晶質であるIZO膜を厚さが50nmとなるように成膜した。その上に、ArとO2の混合ガス雰囲気中で、DCスパッタリング法を用いて、ZnOとMgOとが質量比で88wt%:12wt%に調整されたスパッタリングターゲットにて、六方晶系のウルツ鉱型構造を有するMg添加ZnO薄膜を30nmの厚さで形成した。これにより、IZO膜の上に、Mg添加ZnO薄膜を形成した。配向制御層の全体の厚さは、80nmとした。
配向制御層の上に、ArとO2の混合ガス雰囲気中で、DCマグネトロンスパッタ法を用いて、六方晶系金属層である、厚さ30nmのTi膜を第1の電極として成膜した。
第1の電極の上に、KrとO2の混合ガス雰囲気中でガス圧を0.7Paに調整し、DCスパッタリング法を用いて、ZnOとMgOとが質量比で88wt%:12wt%に調整された、六方晶系のウルツ鉱型構造を有するMg添加ZnO薄膜を圧電体層として成膜した。圧電体層の厚さは、500nmとした。
準備したサンプル内のKrの含有割合(Kr元素/含有元素)を、ラザフォード後方散乱分析法(RBS)を用いて、Pelletron 3SDH及び5SDH-2(NEC社製)を使用し、下記測定条件及び評価基準に基づいて、圧電層内に含まれるKr含有量を評価した。なお、含有元素とは、ZnOとMgOとをいう。サンプルの圧電体層中のKr含有量の検出下限値は、0.01atm%であった。
((測定条件))
・入射イオン:4He++
・入射エネルギー:2300keV
・入射角:0deg
・散乱角:140deg
・試料電流:10nA
・ビーム径:2mmφ
・面内回転:無
・照射量:80μC
準備したサンプルの表面を、X線回折装置(SmartLab、リガク社製)を用いて、XRC法により、下記の測定条件で、サンプルに含まれる主成分の結晶の(0002)面からの反射を測定したときに得られるロッキングカーブの、ピーク波形の半値全幅(FWHM)を求め、圧電体層の結晶配向度とした。
((測定条件))
・測定モード:ωスキャン
・スキャン範囲:0°~34.2°
・ステップ幅:0.1°
・スピード/計数時間:4°/min
・入射スリット:1.0mm
・入射&受光ソーラースリット:5°
・長手制限スリット:10mm
・受光光学素子:PSA Open
準備したサンプルの膜密度を、X線回折装置(SmartLab、リガク社製)を用いて、X線反射率測定法により、下記の測定条件で測定し、圧電体層の膜密度を求めた。
((測定条件))
・測定範囲:0.2°~8.0°
・測定間隔:0.01°
・スピード/計数時間:0.5°/min
・発散スリット:0.05mm
準備したサンプルをX線回折装置(SmartLab、リガク社製)を用いて、下記の測定条件及び解析条件の下、2θχ/φスキャンによるインプレーンX線回折法により結晶格子のa軸長及びc軸長を解析し、結晶格子の軸比c/aを求めた。軸比c/aが1.590以下の場合は「良好」であると評価し、軸比c/aが1.590を超える場合は、「不良」であると評価した。軸比c/aの測定結果を図9に示す。
((測定条件))
・スキャン軸:2θχ/φスキャン
・入射角:0.3°
・スキャン範囲:5°~110°
・ステップ:0.1°
・スキャンスピード:2.0°/min
(解析方法)
X線回折装置のSmartLab解析ソフト(SmartLab StudioII)を用いて得られた回折ピークを用いてフィッティングを行い、結晶構造データベースCODを用いてZnO(データベース番号1011258)で解析を行い、a軸長及びc軸長を算出した。
準備したサンプルを3cm四方に切り出し、圧電体層が形成された面を下側にして基準となる面に静置し、その基準面とサンプルの各四隅との垂直方向における高さの平均値を算出することで、圧電体層の反り量を求めた。反り量が10mm以下である場合、フィルム反りは良好であると評価した。
作製した圧電素子の圧電特性を評価した。
ステージ上に圧電素子を設置して第1の電極をステージ上に引き出し、圧電素子の上部に位置する圧子を設定圧力で印加することで圧電層内に格子歪みを生じさせ、その格子歪みに由来する膜厚方向の分極による発生電荷を評価した。初期圧力との圧力差を1N~9Nまで変化させ、発生電荷量を印加圧力で除した値を算出し、圧電特性として評価した。
実施例1において、圧電体層の厚さを1000nmに変更したこと以外は、実施例1と同様にして圧電素子を作製した。圧電体層内のKr元素の含有割合と、圧電体層の、厚さ、結晶配向度、膜密度、軸比c/a及び反り量と、圧電素子の圧電特性(d33値)の測定結果を表1に示す。
実施例1において、圧電体層の成膜ガス圧を0.7Paから1.6Paに変更したこと以外は、実施例1と同様にして圧電素子を作製した。圧電体層内のKr元素の含有割合と、圧電体層の、厚さ、結晶配向度、膜密度、軸比c/a及び反り量と、圧電素子の圧電特性(d33値)の測定結果を表1に示す。
実施例1において、圧電層の作製を以下のように変更したこと以外は、実施例1と同様にして圧電素子を作製した。
(圧電体層の作製)
第1の電極の上に、ArとO2の混合ガス雰囲気中で、ガス圧を0.2Paに調整し、DCスパッタリング法を用いて、ZnOとMgOとが質量比で88wt%:12wt%に調整された、六方晶系のウルツ鉱型構造を有するMg添加ZnO薄膜を圧電体層として成膜した。
比較例1において、圧電体層の作製時において、ガス圧を0.2Paから0.7Paに変更したこと以外は、比較例1と同様にして圧電素子を作製した。
比較例1において、圧電体層の作製時において、ガス圧を0.2Paから3.0Paに変更したこと以外は、比較例1と同様にして圧電素子を作製した。
実施例1において、圧電体層の作製時において、ガス圧を0.7Paから0.2Paに変更したこと以外は、実施例1と同様にして圧電素子を作製した。
11、21、27 基材
20A、20B、20C、20D、20E 圧電素子
22 配向制御層
23 第1の電極
24 圧電体層
25 第2の電極
26 粘着層
Claims (8)
- ウルツ鉱型の結晶構造を有する圧電材料を主成分として備え、
Krを含む添加元素を有し、
前記圧電材料は、Zn、Al、Ga、Cd及びSiからなる群より選択される一種の成分を陽性元素として含み、
前記圧電材料中の含有元素の含有量に対するKr元素の含有量の割合が、0.01atm%~0.05atm%である圧電体膜。 - 前記圧電材料は、ZnOを含み、
結晶配向度が5°以下であり、膜密度が5.1g/cm3以下である請求項1に記載の圧電体膜。 - 前記圧電材料は、ZnOを含み、
前記圧電材料に含まれる前記結晶構造の軸比c/aが、1.59以下である請求項1又は2記載の圧電体膜。 - 前記圧電体膜の厚さが、100nm~3000nmである請求項1~3の何れか一項に記載の圧電体膜。
- 請求項1~4の何れか一項に記載の圧電体膜の製造方法であって、
Krと酸素を含む混合ガス雰囲気において、Znを含むターゲットを用いたスパッタリング法により、基材上にKrを含みつつ前記圧電材料をスパッタリングすることにより前記圧電体膜を成膜する圧電体膜の製造方法。 - 前記スパッタリング法が、ZnOからなるターゲットとMgOからなるターゲットを用いた多元スパッタリング法、又はZnO及びMgOの合金からなるターゲットを用いた一次元スパッタリング法である請求項5に記載の圧電体膜の製造方法。
- 基材の上に、電極及び圧電体層を備え、
前記圧電体層が、請求項1~4の何れか一項に記載の圧電体膜である圧電素子。 - 請求項7に記載の圧電素子を備える圧電デバイス。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202280022562.9A CN117016059A (zh) | 2021-03-30 | 2022-03-28 | 压电体膜、压电体膜的制造方法、压电组件和压电器件 |
JP2023511277A JPWO2022210563A1 (ja) | 2021-03-30 | 2022-03-28 | |
US18/283,607 US20240172564A1 (en) | 2021-03-30 | 2022-03-28 | Piezoelectric film, method of producing piezoelectric film, piezoelectric element, and piezoelectric device |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2021056823 | 2021-03-30 | ||
JP2021-056823 | 2021-03-30 | ||
JP2021-158022 | 2021-09-28 | ||
JP2021158022 | 2021-09-28 | ||
JP2022046696 | 2022-03-23 | ||
JP2022-046696 | 2022-03-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2022210563A1 true WO2022210563A1 (ja) | 2022-10-06 |
Family
ID=83459231
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2022/015069 WO2022210563A1 (ja) | 2021-03-30 | 2022-03-28 | 圧電体膜、圧電体膜の製造方法、圧電素子及び圧電デバイス |
Country Status (4)
Country | Link |
---|---|
US (1) | US20240172564A1 (ja) |
JP (1) | JPWO2022210563A1 (ja) |
TW (1) | TW202306929A (ja) |
WO (1) | WO2022210563A1 (ja) |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004101842A1 (ja) * | 2003-05-15 | 2004-11-25 | National Institute Of Advanced Industrial Science And Technology | ウルツ鉱型薄膜、ウルツ鉱型結晶層を含む積層体、および、これらの製造方法 |
JP2005351664A (ja) * | 2004-06-08 | 2005-12-22 | National Institute Of Advanced Industrial & Technology | ケーブル状圧電センサ |
JP2013004707A (ja) * | 2011-06-16 | 2013-01-07 | Hitachi Cable Ltd | 圧電膜素子及び圧電膜デバイス |
WO2020049880A1 (ja) * | 2018-09-03 | 2020-03-12 | 日東電工株式会社 | 透明導電性圧電フィルムの製造方法および製造装置 |
WO2020066930A1 (ja) * | 2018-09-28 | 2020-04-02 | 日東電工株式会社 | 圧電デバイス、及び圧電デバイスの製造方法 |
WO2020067330A1 (ja) * | 2018-09-28 | 2020-04-02 | 日東電工株式会社 | 圧電デバイス、及び圧電デバイスの製造方法 |
JP2020088281A (ja) * | 2018-11-29 | 2020-06-04 | Tdk株式会社 | 圧電薄膜素子 |
-
2022
- 2022-03-28 WO PCT/JP2022/015069 patent/WO2022210563A1/ja active Application Filing
- 2022-03-28 JP JP2023511277A patent/JPWO2022210563A1/ja active Pending
- 2022-03-28 US US18/283,607 patent/US20240172564A1/en active Pending
- 2022-03-29 TW TW111111828A patent/TW202306929A/zh unknown
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004101842A1 (ja) * | 2003-05-15 | 2004-11-25 | National Institute Of Advanced Industrial Science And Technology | ウルツ鉱型薄膜、ウルツ鉱型結晶層を含む積層体、および、これらの製造方法 |
JP2005351664A (ja) * | 2004-06-08 | 2005-12-22 | National Institute Of Advanced Industrial & Technology | ケーブル状圧電センサ |
JP2013004707A (ja) * | 2011-06-16 | 2013-01-07 | Hitachi Cable Ltd | 圧電膜素子及び圧電膜デバイス |
WO2020049880A1 (ja) * | 2018-09-03 | 2020-03-12 | 日東電工株式会社 | 透明導電性圧電フィルムの製造方法および製造装置 |
WO2020066930A1 (ja) * | 2018-09-28 | 2020-04-02 | 日東電工株式会社 | 圧電デバイス、及び圧電デバイスの製造方法 |
WO2020067330A1 (ja) * | 2018-09-28 | 2020-04-02 | 日東電工株式会社 | 圧電デバイス、及び圧電デバイスの製造方法 |
JP2020088281A (ja) * | 2018-11-29 | 2020-06-04 | Tdk株式会社 | 圧電薄膜素子 |
Non-Patent Citations (1)
Title |
---|
YING MINJU, SAEEDI AHMAD M. A., YUAN MIAOMIAO, ZHANG XIA, LIAO BIN, ZHANG XU, MEI ZENGXIA, DU XIAOLONG, HEALD STEVE M., FOX A. MAR: "Extremely large d 0 magnetism in krypton implanted polar ZnO films", JOURNAL OF MATERIALS CHEMISTRY C, ROYAL SOCIETY OF CHEMISTRY, GB, vol. 7, no. 5, 31 January 2019 (2019-01-31), GB , pages 1138 - 1145, XP055972965, ISSN: 2050-7526, DOI: 10.1039/C8TC05929B * |
Also Published As
Publication number | Publication date |
---|---|
TW202306929A (zh) | 2023-02-16 |
US20240172564A1 (en) | 2024-05-23 |
JPWO2022210563A1 (ja) | 2022-10-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN111244263B (zh) | 压电薄膜元件 | |
TWI765013B (zh) | 壓電裝置、以及壓電裝置的製造方法 | |
CN112740429B (zh) | 压电器件及压电器件的制造方法 | |
JP7315424B2 (ja) | 圧電デバイス、及び圧電デバイスの製造方法 | |
JP2011181764A (ja) | 圧電体素子及びその製造方法 | |
JP7077287B2 (ja) | 圧電デバイス、及び圧電デバイスの製造方法 | |
WO2022210182A1 (ja) | 圧電体膜の製造方法、圧電素子の製造方法及び圧電デバイスの製造方法 | |
WO2022210563A1 (ja) | 圧電体膜、圧電体膜の製造方法、圧電素子及び圧電デバイス | |
WO2022163722A1 (ja) | 圧電素子、及びこれを用いたセンサ及びアクチュエータ | |
CN117016059A (zh) | 压电体膜、压电体膜的制造方法、压电组件和压电器件 | |
WO2022210438A1 (ja) | 圧電素子の製造方法及び圧電デバイスの製造方法 | |
WO2023171728A1 (ja) | センサデバイス | |
WO2024070712A1 (ja) | 圧電素子及び電子機器 | |
WO2024070711A1 (ja) | 圧電素子及び電子機器 | |
TW202423274A (zh) | 壓電元件及電子設備 | |
TW202431775A (zh) | 壓電元件和電子設備 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 22780774 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2023511277 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 202280022562.9 Country of ref document: CN |
|
WWE | Wipo information: entry into national phase |
Ref document number: 18283607 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 22780774 Country of ref document: EP Kind code of ref document: A1 |