JP2019004139A - Laminate board with piezoelectric film, element with piezoelectric film, and method for manufacturing laminate board with piezoelectric film - Google Patents
Laminate board with piezoelectric film, element with piezoelectric film, and method for manufacturing laminate board with piezoelectric film Download PDFInfo
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- 239000003513 alkali Substances 0.000 claims description 6
- 229910000484 niobium oxide Inorganic materials 0.000 claims description 6
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 claims description 6
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- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 7
- 238000011156 evaluation Methods 0.000 description 7
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- 238000007740 vapor deposition Methods 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
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- 239000010949 copper Substances 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
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- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
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- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 2
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- 238000004549 pulsed laser deposition Methods 0.000 description 2
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- 238000012360 testing method Methods 0.000 description 2
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- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241000877463 Lanio Species 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910004121 SrRuO Inorganic materials 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
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- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
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- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
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- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
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- 239000011591 potassium Substances 0.000 description 1
- UKDIAJWKFXFVFG-UHFFFAOYSA-N potassium;oxido(dioxo)niobium Chemical compound [K+].[O-][Nb](=O)=O UKDIAJWKFXFVFG-UHFFFAOYSA-N 0.000 description 1
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- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Description
本発明は、圧電膜を有する積層基板、圧電膜を有する素子および圧電膜を有する積層基板の製造方法に関する。 The present invention relates to a multilayer substrate having a piezoelectric film, an element having a piezoelectric film, and a method for manufacturing a multilayer substrate having a piezoelectric film.
圧電体は、センサやアクチュエータ等の機能性電子部品（デバイス）に広く利用されている。圧電体の材料としては、例えばニオブ酸カリウムナトリウム（ＫＮＮ）が用いられている（例えば特許文献１，２参照）。近年、デバイスに用いられた際、絶縁破壊に至るまでの時間がより長い、すなわち寿命をより長くした圧電体が強く求められるようになっている。 Piezoelectric bodies are widely used for functional electronic components (devices) such as sensors and actuators. As a piezoelectric material, for example, potassium sodium niobate (KNN) is used (see, for example, Patent Documents 1 and 2). In recent years, there has been a strong demand for a piezoelectric material that has a longer time to breakdown, that is, a longer life when used in a device.
本発明の目的は、デバイスに用いられた際、絶縁破壊に至るまでの時間をより長くした圧電膜を有する積層基板およびその関連技術を提供することにある。 An object of the present invention is to provide a laminated substrate having a piezoelectric film having a longer time until dielectric breakdown when used in a device, and a related technique.
本発明の一態様によれば、
基板と、前記基板上に製膜された第１電極膜と、前記第１電極膜上に製膜された圧電膜と、を備える、圧電膜を有する積層基板であって、
前記圧電膜上には、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜が形成されている、圧電膜を有する積層基板およびその関連技術が提供される。
According to one aspect of the invention,
A laminated substrate having a piezoelectric film, comprising: a substrate; a first electrode film formed on the substrate; and a piezoelectric film formed on the first electrode film,
On the piezoelectric film, there is provided a laminated substrate having a piezoelectric film in which an oxide film made of an oxide represented by a composition formula RuO x or IrO x is formed, and a related technique.
本発明によれば、デバイスに用いられた際、絶縁破壊に至るまでの時間を長くした圧電膜を有する積層基板およびその関連技術を提供することが可能となる。 ADVANTAGE OF THE INVENTION According to this invention, when it uses for a device, it becomes possible to provide the laminated substrate which has a piezoelectric film which extended time until dielectric breakdown, and its related technique.
＜本発明の一実施形態＞
以下、本発明の一実施形態について図面を参照しながら説明する。
<One Embodiment of the Present Invention>
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
（１）積層基板の構成
図１に示すように、本実施形態にかかる積層基板１０は、基板１と、基板１上に製膜された第１電極膜としての下部電極膜２と、下部電極膜２上に製膜された圧電膜（圧電薄膜）３と、圧電膜３上に密着層を介して製膜された第２電極膜としての上部電極膜４と、を備えた積層体として構成されている。
(1) Configuration of Laminated Substrate As shown in FIG. 1, a laminated substrate 10 according to this embodiment includes a substrate 1, a lower electrode film 2 as a first electrode film formed on the substrate 1, and a lower electrode. A laminate comprising a piezoelectric film (piezoelectric thin film) 3 formed on the film 2 and an upper electrode film 4 as a second electrode film formed on the piezoelectric film 3 via an adhesion layer. Has been.
基板１としては、熱酸化膜やＣＶＤ（Chemical Vapor Deposition）酸化膜等の表面酸化膜（ＳｉＯ２膜）１ｂが形成された単結晶シリコン（Ｓｉ）基板１ａ、すなわち、表面酸化膜を有するＳｉ基板を好適に用いることができる。また、基板１としては、図２に示すように、その表面にＳｉＯ２以外の絶縁性材料により形成された絶縁膜１ｄを有するＳｉ基板１ａを用いることもできる。また、基板１としては、表面にＳｉ（１００）面やＳｉ（１１１）面等が露出したＳｉ基板１ａ、すなわち、表面酸化膜１ｂや絶縁膜１ｄを有さないＳｉ基板を用いることもできる。また、基板１としては、ＳＯＩ（Silicon On Insulator）基板、石英ガラス（ＳｉＯ２）基板、ガリウム砒素（ＧａＡｓ）基板、サファイア（Ａｌ２Ｏ３）基板、ステンレス等の金属材料により形成された金属基板を用いることもできる。単結晶Ｓｉ基板１ａの厚さは例えば３００〜１０００μｍ、表面酸化膜１ｂの厚さは例えば５〜３０００ｎｍとすることができる。 Si substrate as the substrate 1, having a thermal oxide film or a CVD (Chemical Vapor Deposition) surface oxide film single crystal silicon (SiO 2 film) 1b is formed such as an oxide film (Si) substrate 1a, i.e., the surface oxide film Can be suitably used. As the substrate 1, as shown in FIG. 2, a Si substrate 1a having an insulating film 1d formed of an insulating material other than SiO 2 on its surface can be used. Further, as the substrate 1, it is also possible to use a Si substrate 1a having an exposed Si (100) surface or Si (111) surface, that is, a Si substrate having no surface oxide film 1b or insulating film 1d. Further, as the substrate 1, an SOI (Silicon On Insulator) substrate, a quartz glass (SiO 2 ) substrate, a gallium arsenide (GaAs) substrate, a sapphire (Al 2 O 3 ) substrate, a metal substrate formed of a metal material such as stainless steel. Can also be used. The thickness of the single crystal Si substrate 1a can be set to 300 to 1000 μm, for example, and the thickness of the surface oxide film 1b can be set to 5 to 3000 nm, for example.
下部電極膜２は、例えば、白金（Ｐｔ）を用いて製膜することができる。下部電極膜２は、単結晶膜や多結晶膜（以下、これらをＰｔ膜とも称する）となる。Ｐｔ膜を構成する結晶は、基板１の表面に対して（１１１）面方位に優先配向していることが好ましい。すなわち、Ｐｔ膜の表面（圧電膜３の下地となる面）は、主にＰｔ（１１１）面により構成されていることが好ましい。Ｐｔ膜は、スパッタリング法、蒸着法等の手法を用いて製膜することができる。下部電極膜２は、Ｐｔ以外に、金（Ａｕ）やルテニウム（Ｒｕ）やイリジウム（Ｉｒ）等の各種金属、これらを主成分とする合金、ルテニウム酸ストロンチウム（ＳｒＲｕＯ３）やニッケル酸ランタン（ＬａＮｉＯ３）等の金属酸化物等を用いて製膜することもできる。なお、基板１と下部電極膜２との間には、これらの密着性を高めるため、例えば、チタン（Ｔｉ）、タンタル（Ｔａ）、酸化チタン（ＴｉＯ２）、ニッケル（Ｎｉ）等を主成分とする密着層６が設けられている。密着層６は、スパッタリング法、蒸着法等の手法を用いて製膜することができる。下部電極膜２の厚さは例えば１００〜４００ｎｍ、密着層６の厚さは例えば１〜２００ｎｍとすることができる。 The lower electrode film 2 can be formed using, for example, platinum (Pt). The lower electrode film 2 is a single crystal film or a polycrystalline film (hereinafter also referred to as a Pt film). The crystals constituting the Pt film are preferably preferentially oriented in the (111) plane orientation with respect to the surface of the substrate 1. That is, it is preferable that the surface of the Pt film (the surface serving as the base of the piezoelectric film 3) is mainly composed of the Pt (111) surface. The Pt film can be formed using a technique such as sputtering or vapor deposition. In addition to Pt, the lower electrode film 2 is made of various metals such as gold (Au), ruthenium (Ru) and iridium (Ir), alloys based on these metals, strontium ruthenate (SrRuO 3 ) and lanthanum nickelate (LaNiO). It is also possible to form a film using a metal oxide such as 3 ). In order to improve the adhesion between the substrate 1 and the lower electrode film 2, for example, titanium (Ti), tantalum (Ta), titanium oxide (TiO 2 ), nickel (Ni), or the like is used as a main component. The adhesion layer 6 is provided. The adhesion layer 6 can be formed using a technique such as sputtering or vapor deposition. The thickness of the lower electrode film 2 can be set to 100 to 400 nm, for example, and the thickness of the adhesion layer 6 can be set to 1 to 200 nm, for example.
圧電膜３は、例えば、カリウム（Ｋ）、ナトリウム（Ｎａ）、ニオブ（Ｎｂ）を含み、組成式（Ｋ１−ｙＮａｙ）ＮｂＯ３で表されるアルカリニオブ酸化物、すなわち、ニオブ酸カリウムナトリウム（ＫＮＮ）を用いて製膜することができる。上述の組成式中の係数ｙ［＝Ｎａ／（Ｋ＋Ｎａ）］は、０＜ｙ＜１、好ましくは０.４≦ｙ≦０.７の範囲内の大きさとする。圧電膜３は、ＫＮＮの多結晶膜（以下、ＫＮＮ膜３とも称する）となる。ＫＮＮの結晶構造は、ペロブスカイト構造となる。 The piezoelectric film 3 includes, for example, potassium (K), sodium (Na), niobium (Nb), and an alkali niobium oxide represented by a composition formula (K 1-y Na y ) NbO 3 , that is, potassium niobate. A film can be formed using sodium (KNN). The coefficient y [= Na / (K + Na)] in the above composition formula is 0 <y <1, preferably 0.4 ≦ y ≦ 0.7. The piezoelectric film 3 is a KNN polycrystalline film (hereinafter also referred to as a KNN film 3). The crystal structure of KNN is a perovskite structure.
ＫＮＮ膜３を構成する結晶は、基板１の表面に対して（００１）面方位に優先配向していることが好ましい。すなわち、ＫＮＮ膜３の表面（後述のＲｕＯｘ膜７ａの下地となる面）は、主にＫＮＮ（００１）面により構成されていることが好ましい。基板１の表面に対して（１１１）面方位に優先配向させたＰｔ膜（下部電極膜２）上にＫＮＮ膜３を直接製膜することで、ＫＮＮ膜３を構成する結晶を、基板１の表面に対して（００１）面方位に優先配向させることが容易となる。例えば、ＫＮＮ膜３を構成する結晶群のうち８０％以上の結晶を基板１の表面に対して（００１）面方位に配向させ、ＫＮＮ膜３の表面のうち８０％以上の領域をＫＮＮ（００１）面とすることが可能となる。 The crystals constituting the KNN film 3 are preferably preferentially oriented in the (001) plane orientation with respect to the surface of the substrate 1. That is, it is preferable that the surface of the KNN film 3 (the surface serving as the base of the RuO x film 7a described later) is mainly composed of the KNN (001) plane. By directly forming the KNN film 3 on the Pt film (lower electrode film 2) preferentially oriented in the (111) plane direction with respect to the surface of the substrate 1, the crystals constituting the KNN film 3 can be obtained. It becomes easy to preferentially orient the (001) plane orientation with respect to the surface. For example, 80% or more of the crystals constituting the KNN film 3 are oriented in the (001) plane orientation with respect to the surface of the substrate 1, and 80% or more of the surface of the KNN film 3 is aligned with KNN (001 ) Surface.
ＫＮＮ膜３は、スパッタリング法、ＰＬＤ（Pulsed Laser Deposition）法、ゾルゲル法等の手法を用いて製膜することができる。ＫＮＮ膜３の厚さは例えば０．５〜５μｍとすることができる。ＫＮＮ膜３の組成比は、例えば、スパッタリング製膜時に用いるターゲット材の組成を制御することで調整可能である。ターゲット材は、例えば、Ｋ２ＣＯ３粉末、Ｎａ２ＣＯ３粉末、Ｎｂ２Ｏ５粉末等を混合させて焼成すること等により作製することができる。この場合、ターゲット材の組成は、Ｋ２ＣＯ３粉末、Ｎａ２ＣＯ３粉末、Ｎｂ２Ｏ５粉末等の混合比率を調整することで制御することができる。 The KNN film 3 can be formed using a technique such as sputtering, PLD (Pulsed Laser Deposition), or sol-gel. The thickness of the KNN film 3 can be set to 0.5 to 5 μm, for example. The composition ratio of the KNN film 3 can be adjusted, for example, by controlling the composition of the target material used during sputtering film formation. The target material can be produced, for example, by mixing and baking K 2 CO 3 powder, Na 2 CO 3 powder, Nb 2 O 5 powder, or the like. In this case, the composition of the target material can be controlled by adjusting the mixing ratio of K 2 CO 3 powder, Na 2 CO 3 powder, Nb 2 O 5 powder, and the like.
ＫＮＮ膜３は、銅（Ｃｕ）、マンガン（Ｍｎ）、リチウム（Ｌｉ）、Ｔａ、アンチモン（Ｓｂ）等のＫ、Ｎａ、Ｎｂ以外の元素を、５ａｔ％以下の範囲内で含んでいてもよい。 The KNN film 3 may contain elements other than K, Na, Nb, such as copper (Cu), manganese (Mn), lithium (Li), Ta, and antimony (Sb) within a range of 5 at% or less. .
上部電極膜４は、例えば、Ｐｔ、Ａｕ、アルミニウム（Ａｌ）、Ｃｕ等の各種金属やこれらの合金を用いて製膜することができる。上部電極膜４は、スパッタリング法、蒸着法、メッキ法、金属ペースト法等の手法を用いて製膜することができる。上部電極膜４は、下部電極膜２のようにＫＮＮ膜３の結晶構造に大きな影響を与えるものではない。そのため、上部電極膜４の材料、結晶構造、製膜手法は特に限定されない。上部電極膜４の厚さは例えば１００〜５０００ｎｍとすることができる。 The upper electrode film 4 can be formed using, for example, various metals such as Pt, Au, aluminum (Al), Cu, and alloys thereof. The upper electrode film 4 can be formed using a technique such as sputtering, vapor deposition, plating, or metal paste. The upper electrode film 4 does not significantly affect the crystal structure of the KNN film 3 unlike the lower electrode film 2. Therefore, the material, crystal structure, and film forming method of the upper electrode film 4 are not particularly limited. The thickness of the upper electrode film 4 can be set to, for example, 100 to 5000 nm.
ＫＮＮ膜３と上部電極膜４との間、すなわちＫＮＮ膜３上には、これらの間の密着性を高める密着層として、組成式ＲｕＯｘで表される酸化物からなる膜（酸化膜）７ａ（以下、ＲｕＯｘ膜７ａとも称する）が製膜されている。また、この密着層として、図３に示すように、組成式ＩｒＯｘで表される酸化物からなる膜７ｂ（以下、ＩｒＯｘ膜７ｂとも称する）が製膜されていてもよい。 Between the KNN film 3 and the upper electrode film 4, that is, on the KNN film 3, a film (oxide film) 7 a made of an oxide represented by the composition formula RuO x is used as an adhesion layer for improving the adhesion between them. (Hereinafter also referred to as RuO x film 7a) is formed. Further, as this adhesion layer, as shown in FIG. 3, a film 7b made of an oxide represented by the composition formula IrO x (hereinafter also referred to as an IrO x film 7b) may be formed.
ＲｕＯｘ膜７ａは、スパッタリング法、化学気相成長（ＣＶＤ）法、蒸着法等の手法を用いて製膜することができる。ＲｕＯｘ膜７ａは、下部電極膜２のようにＫＮＮ膜３の結晶構造に大きな影響を与えるものではない。そのため、ＲｕＯｘ膜７ａの結晶構造、製膜手法は特に限定されない。ＲｕＯｘ膜７ａの組成比、すなわち上述の組成式中の係数ｘの値は、スパッタリング製膜時の雰囲気ガス、例えばアルゴン（Ａｒ）ガスと酸素（Ｏ２）ガスとの混合ガス（Ａｒ／Ｏ２混合ガス）中におけるＯ２ガス比率を制御すること等により調整可能である。上述のＯ２ガス比率が高くなるほど、係数ｘの値が大きくなり、Ｏ２ガス比率が小さくなるほど、係数ｘの値が小さくなる傾向がある。また、スパッタリング製膜時に用いるターゲット材として、係数ｘが０＜ｘ＜２の範囲内であるＲｕＯｘ膜７ａを製膜する際は、ルテニウム（Ｒｕ）の金属材料により形成されたターゲット材を用いることが好ましく、係数ｘが２≦ｘ、好ましくは２＜ｘの範囲内であるＲｕＯｘ膜７ａを製膜する際は、ＲｕＯ２粉末を焼成すること等により作製したターゲット材を用いることが好ましい。ＲｕＯｘ膜７ａの厚さは例えば２〜３０ｎｍ、好ましくは５〜３０ｎｍとすることができる。これらの点については、ＩｒＯｘ膜７ｂについても同様のことが言える。なお、係数ｘが０＜ｘ＜２の範囲内であるＩｒＯｘ膜７ｂを製膜する際は、イリジウム（Ｉｒ）の金属材料により形成されたターゲット材を用いることが好ましく、係数ｘが２≦ｘ、好ましくは２＜ｘの範囲内であるＩｒＯｘ膜７ｂを製膜する際は、ＩｒＯ２粉末を焼成すること等により作製したターゲット材を用いることが好ましい。 The RuO x film 7a can be formed using a technique such as sputtering, chemical vapor deposition (CVD), or vapor deposition. The RuO x film 7 a does not significantly affect the crystal structure of the KNN film 3 unlike the lower electrode film 2. Therefore, the crystal structure of the RuO x film 7a and the film forming method are not particularly limited. The composition ratio of the RuO x film 7a, that is, the value of the coefficient x in the above-described composition formula is the atmospheric gas during sputtering film formation, for example, a mixed gas (Ar / O) of argon (Ar) gas and oxygen (O 2 ) gas. It can be adjusted by controlling the O 2 gas ratio in the ( 2 mixed gas). As O 2 gas ratio described above is high, the value of coefficient x increases, the more O 2 gas ratio is reduced, tends to the value of the coefficient x is reduced. Further, as a target material used during sputtering film formation, when forming the RuO x film 7a having a coefficient x in the range of 0 <x <2, a target material formed of a ruthenium (Ru) metal material is used. It is preferable that when forming the RuO x film 7a having a coefficient x in the range of 2 ≦ x, preferably 2 <x, it is preferable to use a target material prepared by firing RuO 2 powder or the like. . The thickness of the RuO x film 7a can be set to, for example, 2 to 30 nm, preferably 5 to 30 nm. The same applies to the IrO x film 7b. When forming the IrO x film 7b in which the coefficient x is in the range of 0 <x <2, it is preferable to use a target material formed of a metal material of iridium (Ir), and the coefficient x is 2 ≦ When forming the IrO x film 7b in the range of x, preferably 2 <x, it is preferable to use a target material produced by firing IrO 2 powder or the like.
（２）圧電膜デバイスの構成
図４に、本実施形態における圧電膜を有するデバイス３０（以下、圧電膜デバイス３０とも称する）の概略構成図を示す。圧電膜デバイス３０は、上述の積層基板１０を所定の形状に成形して得られる圧電膜を有する素子２０（以下、圧電膜素子２０とも称する）と、圧電膜素子２０に接続される電圧検出手段１１ａまたは電圧印加手段１１ｂと、を少なくとも備えて構成される。
(2) Configuration of Piezoelectric Film Device FIG. 4 shows a schematic configuration diagram of a device 30 having a piezoelectric film in the present embodiment (hereinafter also referred to as a piezoelectric film device 30). The piezoelectric film device 30 includes an element 20 having a piezoelectric film (hereinafter, also referred to as a piezoelectric film element 20) obtained by molding the above-described laminated substrate 10 into a predetermined shape, and a voltage detection unit connected to the piezoelectric film element 20. 11a or voltage application means 11b.
電圧検出手段１１ａを、圧電膜素子２０の下部電極膜２と上部電極膜４との間に接続することで、圧電膜デバイス３０をセンサとして機能させることができる。ＫＮＮ膜３が何らかの物理量の変化に伴って変形すると、その変形によって下部電極膜２と上部電極膜４との間に電圧が発生する。この電圧を電圧検出手段１１ａによって検出することで、ＫＮＮ膜３に印加された物理量の大きさを測定することができる。この場合、圧電膜デバイス３０の用途としては、例えば、角速度センサ、超音波センサ、圧カセンサ、加速度センサ等が挙げられる。 By connecting the voltage detection means 11a between the lower electrode film 2 and the upper electrode film 4 of the piezoelectric film element 20, the piezoelectric film device 30 can function as a sensor. When the KNN film 3 is deformed with any change in physical quantity, a voltage is generated between the lower electrode film 2 and the upper electrode film 4 due to the deformation. By detecting this voltage by the voltage detection means 11a, the magnitude of the physical quantity applied to the KNN film 3 can be measured. In this case, examples of the application of the piezoelectric film device 30 include an angular velocity sensor, an ultrasonic sensor, a pressure sensor, and an acceleration sensor.
電圧印加手段１１ｂを、圧電膜素子２０の下部電極膜２と上部電極膜４との間に接続することで、圧電膜デバイス３０をアクチュエータとして機能させることができる。電圧印加手段１１ｂにより下部電極膜２と上部電極膜４との間に電圧を印加することで、ＫＮＮ膜３を変形させることができる。この変形動作により、圧電膜デバイス３０に接続された各種部材を作動させることができる。この場合、圧電膜デバイス３０の用途としては、例えば、インクジェットプリンタ用のヘッド、スキャナー用のＭＥＭＳミラー、超音波発生装置用の振動子等が挙げられる。 By connecting the voltage applying means 11b between the lower electrode film 2 and the upper electrode film 4 of the piezoelectric film element 20, the piezoelectric film device 30 can function as an actuator. The KNN film 3 can be deformed by applying a voltage between the lower electrode film 2 and the upper electrode film 4 by the voltage applying means 11b. With this deformation operation, various members connected to the piezoelectric film device 30 can be operated. In this case, the application of the piezoelectric film device 30 includes, for example, a head for an ink jet printer, a MEMS mirror for a scanner, a vibrator for an ultrasonic generator, and the like.
（３）積層基板、圧電膜素子、圧電膜デバイスの製造方法
続いて、上述の積層基板１０の製造方法について説明する。まず、基板１のいずれかの主面上に下部電極膜２を製膜する。なお、いずれかの主面上に下部電極膜２が予め製膜された基板１を用意してもよい。続いて、下部電極膜２上に、例えばスパッタリング法を用いてＫＮＮ膜３を製膜した後、ＫＮＮ膜３（ＫＮＮ膜３を有する積層体）に対して、所定温度（例えば５００℃）の条件下で所定時間（例えば２時間）、アニール（熱処理）を行う。その後、ＫＮＮ膜３上に、例えばスパッタリング法を用いてＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂを製膜し、ＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂ上に上部電極膜４を製膜することで、積層基板１０が得られる。
(3) Manufacturing Method of Multilayer Substrate, Piezoelectric Film Element, and Piezoelectric Film Device Next, a manufacturing method of the above-described multilayer substrate 10 will be described. First, the lower electrode film 2 is formed on any main surface of the substrate 1. In addition, you may prepare the board | substrate 1 by which the lower electrode film 2 was formed into a film beforehand on either main surface. Subsequently, after the KNN film 3 is formed on the lower electrode film 2 by using, for example, a sputtering method, a condition of a predetermined temperature (for example, 500 ° C.) is applied to the KNN film 3 (laminated body having the KNN film 3). Below, annealing (heat treatment) is performed for a predetermined time (for example, 2 hours). Thereafter, a RuO x film 7a or an IrO x film 7b is formed on the KNN film 3 by using, for example, a sputtering method, and an upper electrode film 4 is formed on the RuO x film 7a or the IrO x film 7b. The laminated substrate 10 is obtained.
ＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂおよび上部電極膜４の製膜後に積層基板１０に対してアニールを行ってもよい。 The laminated substrate 10 may be annealed after the RuO x film 7a or the IrO x film 7b and the upper electrode film 4 are formed.
上述の積層基板１０に対して行うアニール条件としては、
アニール温度（積層基板１０の温度）：６００℃以上、好ましくは６００℃以上８００℃以下、より好ましくは７００℃
アニール時間：０．５〜１２時間、好ましくは１〜６時間、より好ましくは２〜３時間
アニール雰囲気：大気または酸素雰囲気
が例示される。ただし、このアニールは行わなくてもよい。
As the annealing conditions for the laminated substrate 10 described above,
Annealing temperature (temperature of laminated substrate 10): 600 ° C. or higher, preferably 600 ° C. or higher and 800 ° C. or lower, more preferably 700 ° C.
Annealing time: 0.5 to 12 hours, preferably 1 to 6 hours, more preferably 2 to 3 hours Annealing atmosphere: air or oxygen atmosphere is exemplified. However, this annealing need not be performed.
そして、この積層基板１０を所定の形状に成形することで、圧電膜素子２０が得られ、圧電膜素子２０に電圧検出手段１１ａまたは電圧印加手段１１ｂを接続することで、圧電膜デバイス３０が得られる。 A piezoelectric film element 20 is obtained by forming the laminated substrate 10 into a predetermined shape, and the piezoelectric film device 30 is obtained by connecting the voltage detection means 11a or the voltage application means 11b to the piezoelectric film element 20. It is done.
（４）本実施形態により得られる効果
本実施形態によれば、以下に示す１つまたは複数の効果が得られる。
(4) Effects Obtained by the Present Embodiment According to the present embodiment, one or more effects shown below can be obtained.
（ａ）ＫＮＮ膜３と上部電極膜４との間に、ＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂを設けることで、本実施形態にかかる積層基板１０を用いて作製した圧電膜デバイス３０において、ＫＮＮ膜３が絶縁破壊に至るまでの時間を長くすること、すなわちＫＮＮ膜３の寿命を長くすることが可能となる。例えば、積層基板１０の温度が２００℃となるように加熱した状態で、下部電極膜２と上部電極膜４との間に−３００ｋＶ／ｃｍの電界（−６０Ｖの電圧）を印加する高加速寿命試験（Ｈｉｇｈｌｙ Ａｃｃｅｌｅｒａｔｅｄ Ｌｉｆｅ Ｔｅｓｔ、略称：ＨＡＬＴ）を行った際、電界印加開始からＫＮＮ膜３が絶縁破壊に至るまでの時間を３３００秒以上とすることが可能となる。なお、本実施形態では、ＫＮＮ膜３に流れるリーク電流密度が３０ｍＡ／ｃｍ２を超えた時点でＫＮＮ膜３が絶縁破壊に至ったとみなしている。 (A) By providing the RuO x film 7 a or the IrO x film 7 b between the KNN film 3 and the upper electrode film 4, in the piezoelectric film device 30 manufactured using the multilayer substrate 10 according to the present embodiment, the KNN It is possible to increase the time until the dielectric breakdown of the film 3, that is, increase the life of the KNN film 3. For example, a high accelerated lifetime in which an electric field of −300 kV / cm (−60 V voltage) is applied between the lower electrode film 2 and the upper electrode film 4 in a state where the temperature of the laminated substrate 10 is heated to 200 ° C. When a test (High Accelerated Life Test, abbreviated as HALT) is performed, the time from the start of electric field application to the dielectric breakdown of the KNN film 3 can be 3300 seconds or more. In the present embodiment, it is considered that the KNN film 3 has reached dielectric breakdown when the density of the leakage current flowing through the KNN film 3 exceeds 30 mA / cm 2 .
特に、ＲｕＯｘ膜７ａを形成することで、ＩｒＯｘ膜７ｂを形成する場合よりも、ＫＮＮ膜３の寿命をさらに長くすることが可能となる。例えば、上述のＨＡＬＴによるＫＮＮ膜３の寿命を７６００秒以上とすることが可能となる。 In particular, the lifetime of the KNN film 3 can be further increased by forming the RuO x film 7a as compared with the case of forming the IrO x film 7b. For example, the lifetime of the KNN film 3 by HALT described above can be made 7600 seconds or longer.
ここで、上述の本実施形態の手法に対し、ＫＮＮ膜と上部電極膜との間に、チタン（Ｔｉ）からなる膜（Ｔｉ膜）や組成式ＴｉＯｘで表される酸化物からなる膜（ＴｉＯｘ膜）を設ける手法も考えられる。しかしながら、この手法により得られた積層基板を加工して作製した圧電膜デバイスでは、本実施形態にかかる圧電膜デバイス３０よりも、上述のＨＡＬＴによるＫＮＮ膜の寿命が短くなる。これは、何らかの要因によりＴｉがＫＮＮ膜中に拡散（移動）し、このＴｉがＫＮＮ膜の寿命に悪影響を及ぼしているものと考えられる。 Here, in contrast to the method of the present embodiment described above, a film (Ti film) made of titanium (Ti) or a film made of an oxide represented by the composition formula TiO x (between the KNN film and the upper electrode film ( A method of providing a (TiO x film) is also conceivable. However, in the piezoelectric film device manufactured by processing the multilayer substrate obtained by this method, the lifetime of the above-described HALT KNN film is shorter than that of the piezoelectric film device 30 according to the present embodiment. This is considered to be because Ti is diffused (moved) into the KNN film for some reason, and this Ti has an adverse effect on the lifetime of the KNN film.
（ｂ）本実施形態にかかる積層基板１０を用いて作製した圧電膜デバイス３０は、従来の圧電膜デバイスよりも、良好な強誘電性を有する。例えば、ＫＮＮ膜３に電界を印加した際の飽和分極量（Ｐｍａｘ−）の絶対値が２３μＣ／ｃｍ２以上（｜Ｐｍａｘ−｜≧２３μＣ／ｃｍ２）であり、残留分極量（Ｐｒ−）の絶対値が１４μＣ／ｃｍ２以上（｜Ｐｒ−｜≧１４μＣ／ｃｍ２）である。なお、飽和分極量とは電界を印加し続けても分極量が増加しなくなったときの分極量であり、残留分極量とは、飽和分極量に達した後、印加電界をゼロに戻したときの分極量である。 (B) The piezoelectric film device 30 manufactured using the multilayer substrate 10 according to the present embodiment has better ferroelectricity than the conventional piezoelectric film device. For example, the absolute value of the saturation polarization amount (P max− ) when an electric field is applied to the KNN film 3 is 23 μC / cm 2 or more (| P max− | ≧ 23 μC / cm 2 ), and the residual polarization amount (P r The absolute value of − ) is 14 μC / cm 2 or more (| P r− | ≧ 14 μC / cm 2 ). The saturation polarization amount is the polarization amount when the polarization amount does not increase even if the electric field is continuously applied, and the residual polarization amount is when the applied electric field is returned to zero after reaching the saturation polarization amount. Is the amount of polarization.
（ｃ）ＫＮＮ膜３と上部電極膜４との間に、ＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂを設けることで、ＫＮＮ膜３の強誘電性を高めることが可能となる。これに対し、Ｔｉ膜やＴｉＯｘ膜を有する積層基板を加工して作製した上述の従来の圧電膜デバイスは、本実施形態にかかる圧電膜デバイス３０よりも強誘電性が低くなることを、本願発明者は確認している。 (C) By providing the RuO x film 7a or the IrO x film 7b between the KNN film 3 and the upper electrode film 4, the ferroelectricity of the KNN film 3 can be enhanced. In contrast, the above-described conventional piezoelectric film device manufactured by processing a laminated substrate having a Ti film or a TiO x film has lower ferroelectricity than the piezoelectric film device 30 according to the present embodiment. The inventor has confirmed.
（ｄ）ＲｕＯｘ膜７ａの厚さを２〜３０ｎｍ、好ましくは５〜３０ｎｍとすることで、上述の寿命向上効果、強誘電性向上効果を得ることができるとともに、圧電膜デバイス３０の性能の低下を抑制することが可能となる。なお、ＩｒＯｘ膜７ｂについても同様のことが言える。 (D) By setting the thickness of the RuO x film 7a to 2 to 30 nm, preferably 5 to 30 nm, the above-described lifetime improvement effect and ferroelectricity improvement effect can be obtained, and the performance of the piezoelectric film device 30 can be improved. It is possible to suppress the decrease. The same applies to the IrO x film 7b.
ＲｕＯｘ膜７ａの厚さが２ｎｍ未満であると、ＲｕＯｘ膜７ａの面内膜厚が不均一となったり、不連続な膜となったりすることがある。このため、上述の寿命向上効果や強誘電性向上効果が充分に得られないことがある。ＲｕＯｘ膜７ａの厚さを２ｎｍ以上とすることで、これらの課題を解決でき、上述の寿命向上効果、強誘電性向上効果を得ることができる。ＲｕＯｘ膜７ａの厚さを５ｎｍ以上とすることで、上述の課題を確実に解決でき、上述の寿命向上効果、強誘電性向上効果を確実に得ることができる。 When the thickness of the RuO x film 7a is less than 2 nm, the in-plane film thickness of the RuO x film 7a may be non-uniform or a discontinuous film. For this reason, the above-mentioned lifetime improvement effect and ferroelectricity improvement effect may not be sufficiently obtained. By setting the thickness of the RuO x film 7a to 2 nm or more, these problems can be solved, and the above-mentioned lifetime improvement effect and ferroelectricity improvement effect can be obtained. By setting the thickness of the RuO x film 7a to 5 nm or more, the above-mentioned problems can be solved reliably, and the above-mentioned lifetime improvement effect and ferroelectricity improvement effect can be surely obtained.
ＲｕＯｘ膜７ａの厚さが３０ｎｍを超えると、上述のＨＡＬＴによるＫＮＮ膜３の寿命が３３００秒未満となることがある。また、ＲｕＯｘ膜７ａの厚さが厚くなると、ＲｕＯｘ膜７ａ自体が有する膜応力が大きくなり、ＲｕＯｘ膜７ａが剥がれやすくなる。さらに、ＲｕやＩｒは硬い金属材料であることから、ＲｕやＩｒを含むＲｕＯｘ膜７ａやＩｒＯｘ膜７ｂは硬い膜となる。このような硬いＲｕＯｘ膜７ａの厚さが厚くなると、ＫＮＮ膜３を含む振動部が振動（共振）しにくくなり、積層基板１０がセンサに適用された際に感度の低下を招いたり、アクチュエータに適用された際に消費電力の増加を招いたりすることもある。これらの理由から、ＲｕＯｘ膜７ａの厚さは３０ｎｍ以下とすることが好ましい。 When the thickness of the RuO x film 7a exceeds 30 nm, the lifetime of the KNN film 3 by the above-described HALT may be less than 3300 seconds. If the thickness of the RuO x film 7a is increased, the film stress of the RuO x film 7a itself is increased, it becomes easily peeled off RuO x film 7a. Further, since Ru and Ir are hard metal materials, the RuO x film 7a and the IrO x film 7b containing Ru and Ir are hard films. When the thickness of the hard RuO x film 7a is increased, the vibration part including the KNN film 3 is less likely to vibrate (resonate), which may cause a decrease in sensitivity when the multilayer substrate 10 is applied to a sensor, In some cases, it may cause an increase in power consumption. For these reasons, the thickness of the RuO x film 7a is preferably 30 nm or less.
（ｅ）ＲｕＯｘ膜７ａとして、組成式ＲｕＯｘ（０＜ｘ＜２）で表される膜を設けることが、ＲｕＯｘ膜７ａの製膜レートの低下を抑制できる点で、好ましい。 As (e) RuO x film 7a, it is provided with a film represented by the composition formula RuO x (0 <x <2 ), in that it can suppress a decrease in deposition rate of RuO x film 7a, preferred.
上述のように、ＲｕＯｘ膜７ａのスパッタリング製膜時の雰囲気ガス（Ａｒ／Ｏ２混合ガス）中におけるＯ２ガス比率が高くなるほど、係数ｘの値が大きくなり、Ｏ２ガス比率が小さくなるほど、係数ｘの値が小さくなる傾向がある。しかしながら、スパッタリングターゲット材からのＲｕ原子の叩き出しはＡｒガス（イオン化したＡｒ原子（Ａｒ＋））により行われる。このため、上述のＯ２ガス比率が高くなると、すなわちＡｒガス比率が低くなると、ターゲットから叩き出されるＲｕ原子の量（単位時間あたりの量）が少なくなることから、ＲｕＯｘ膜７ａの製膜レートが低下する。Ｏ２ガス比率を例えば５０％以下とすることで、実用的な製膜レートを得ることができ、この場合、係数ｘの値は２未満となる。 As described above, the higher the O 2 gas ratio in the atmospheric gas (Ar / O 2 mixed gas) during the sputtering deposition of the RuO x film 7a, the larger the value of the coefficient x and the smaller the O 2 gas ratio. The value of the coefficient x tends to be small. However, Ru atoms are sputtered from the sputtering target material by Ar gas (ionized Ar atoms (Ar + )). For this reason, when the above-mentioned O 2 gas ratio is high, that is, when the Ar gas ratio is low, the amount of Ru atoms knocked out from the target (amount per unit time) decreases, so that the RuO x film 7a is formed. The rate drops. A practical film forming rate can be obtained by setting the O 2 gas ratio to, for example, 50% or less. In this case, the value of the coefficient x is less than 2.
（ｆ）ＲｕＯｘ膜７ａとして、組成式ＲｕＯｘ（２＜ｘ）で表される膜を設けることが、ＫＮＮ膜３の寿命を確実に長くすることができる点で、好ましい。 (F) It is preferable to provide a film represented by the composition formula RuO x (2 <x) as the RuO x film 7a in that the lifetime of the KNN film 3 can be reliably increased.
組成式ＲｕＯｘ（２＜ｘ）で表される膜を設けることで、ＲｕＯｘ膜７ａからＫＮＮ膜３中へと拡散する酸素（Ｏ）の量を増やすことができる。これにより、ＫＮＮ膜３が絶縁破壊に至る一因であるＫＮＮ膜３中の酸素欠陥を、ＲｕＯｘ膜７ａから拡散した酸素により埋めることができる。その結果、ＫＮＮ膜３の寿命を確実に延ばすことが可能となる。なお、ここでいう「酸素欠陥」とは、例えばＫＮＮ膜３を製膜した後にアニールを行うことでＫＮＮ膜３を構成する結晶内に生じた酸素が抜けた箇所を意味する。 By providing the film represented by the composition formula RuO x (2 <x), the amount of oxygen (O) diffused from the RuO x film 7a into the KNN film 3 can be increased. As a result, oxygen defects in the KNN film 3 that contribute to the dielectric breakdown of the KNN film 3 can be filled with oxygen diffused from the RuO x film 7a. As a result, the lifetime of the KNN film 3 can be reliably extended. Here, the “oxygen defect” means, for example, a portion where oxygen generated in the crystal constituting the KNN film 3 is removed by annealing after the KNN film 3 is formed.
（ｇ）ＲｕＯｘ膜７ａおよび上部電極膜４の製膜後に、６００℃以上の温度条件下で積層基板１０をアニールするか、あるいは、ＲｕＯｘ膜７ａおよび上部電極膜４の製膜後に、積層基板１０のアニールを不実施とすることで、ＫＮＮ膜３の寿命を確実に長くすることが可能となる。なお、アニールを行っても、ＫＮＮ膜３の強誘電性には影響を及ぼさないことを、本願発明者は確認済みである。 (G) After the RuO x film 7a and the upper electrode film 4 are formed, the laminated substrate 10 is annealed under a temperature condition of 600 ° C. or higher, or after the RuO x film 7a and the upper electrode film 4 are formed, By not performing the annealing of the substrate 10, the lifetime of the KNN film 3 can be reliably increased. The inventor of the present application has confirmed that the annealing does not affect the ferroelectricity of the KNN film 3.
これに対し、ＲｕＯｘ膜および上部電極膜の製膜後に６００℃未満（例えば５００℃）の温度条件下で積層基板をアニールする手法も考えられる。しかしながら、積層基板を６００℃未満の温度条件下でアニールすると、ＲｕＯｘ膜および上部電極膜の製膜後に積層基板のアニールを不実施とした場合や、６００℃以上の温度条件下で積層基板をアニールした場合よりも、ＫＮＮ膜の寿命が短くなる。 On the other hand, a method of annealing the laminated substrate under a temperature condition of less than 600 ° C. (for example, 500 ° C.) after forming the RuO x film and the upper electrode film is also conceivable. However, if the laminated substrate is annealed under a temperature condition of less than 600 ° C., annealing of the laminated substrate is not performed after the RuO x film and the upper electrode film are formed, or the laminated substrate is annealed under a temperature condition of 600 ° C. or higher. The lifetime of the KNN film is shorter than when annealing.
（５）変形例
本実施形態は上述の態様に限定されず、例えば以下のように変形することもできる。
(5) Modification This embodiment is not limited to the above-described aspect, and can be modified as follows, for example.
（変形例１）
例えば、基板１と下部電極膜２との間に、ＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂを設けてもよい。すなわち、密着層６として、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる膜を形成してもよい。また例えば、下部電極膜２とＫＮＮ膜３との間に、ＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂを設けてもよい。なお、これらの場合、ＫＮＮ膜３と上部電極膜４との間に、ＲｕＯｘ膜７ａまたはＩｒＯｘ膜７ｂを設けてもよく、設けなくてもよい。これらによっても、上述の実施形態と同様の効果を得ることができる。
(Modification 1)
For example, a RuO x film 7 a or an IrO x film 7 b may be provided between the substrate 1 and the lower electrode film 2. That is, a film made of an oxide represented by the composition formula RuO x or IrO x may be formed as the adhesion layer 6. For example, a RuO x film 7 a or an IrO x film 7 b may be provided between the lower electrode film 2 and the KNN film 3. In these cases, the RuO x film 7 a or the IrO x film 7 b may or may not be provided between the KNN film 3 and the upper electrode film 4. Also by these, the same effect as the above-mentioned embodiment can be acquired.
（変形例２）
上述の積層基板１０を圧電膜素子２０に成形する際、積層基板１０（圧電膜素子２０）を用いて作製した圧電膜デバイス３０をセンサやアクチュエータ等の所望の用途に適用することができる限り、積層基板１０から基板１を除去してもよい。
(Modification 2)
When the above-described multilayer substrate 10 is formed into the piezoelectric film element 20, as long as the piezoelectric film device 30 manufactured using the multilayer substrate 10 (piezoelectric film element 20) can be applied to a desired application such as a sensor or an actuator, The substrate 1 may be removed from the laminated substrate 10.
＜他の実施形態＞
以上、本発明の実施形態を具体的に説明した。但し、本発明は上述の実施形態に限定されるものではなく、その要旨を逸脱しない範囲で種々変更可能である。
<Other embodiments>
The embodiment of the present invention has been specifically described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.
以下、上述の実施形態の効果を裏付ける実験結果について説明する。 Hereinafter, experimental results supporting the effects of the above-described embodiment will be described.
基板として、表面が（１００）面方位、厚さ６１０μｍ、直径６インチ、表面に熱酸化膜（厚さ２００ｎｍ）が形成されたＳｉ基板を用意した。そして、この基板の熱酸化膜上に、第１密着層としてのＴｉ膜（厚さ２ｎｍ）、下部電極膜としてのＰｔ膜（基板の表面に対して（１１１）面方位に優先配向、厚さ２００ｎｍ）、圧電膜としてのＫＮＮ膜（基板の表面に対して（００１）面方位に優先配向、厚さ２μｍ）、第２密着層としてのＲｕＯｘ膜、ＩｒＯｘ膜、ＴｉＯｘ膜（厚さ２ｎｍ）またはＴｉ膜（厚さ２ｎｍ）のいずれかの膜、上部電極膜としてのＰｔ膜（厚さ１００ｎｍ）を順に製膜することで積層基板を作製した。ＲｕＯｘ膜、ＩｒＯｘ膜の厚さは、２．５〜３０ｎｍの範囲内で変化させた。また、ＫＮＮ膜の製膜後であって第２密着層の製膜前に、ＫＮＮ膜を有する積層体を５００℃の条件下で２時間アニールした。また、上部電極膜の製膜後の積層基板のアニールは、不実施とするか、５００℃の温度条件下で２時間、６００℃の温度条件下で２時間、７００℃の温度条件下で２時間の各条件で行った。 As a substrate, a Si substrate having a (100) plane orientation, a thickness of 610 μm, a diameter of 6 inches, and a thermal oxide film (thickness: 200 nm) formed on the surface was prepared. Then, a Ti film (thickness 2 nm) as a first adhesion layer and a Pt film as a lower electrode film (preferential orientation and thickness in the (111) plane direction with respect to the surface of the substrate) on the thermal oxide film of the substrate 200 nm), KNN film as a piezoelectric film (preferential orientation in the (001) plane orientation with respect to the surface of the substrate, thickness 2 μm), RuO x film, IrO x film, TiO x film (thickness as the second adhesion layer) 2 nm) or a Ti film (thickness 2 nm) and a Pt film (thickness 100 nm) as an upper electrode film were formed in this order to produce a laminated substrate. The thicknesses of the RuO x film and the IrO x film were changed within the range of 2.5 to 30 nm. In addition, the laminate having the KNN film was annealed at 500 ° C. for 2 hours after the KNN film was formed and before the second adhesion layer was formed. Also, annealing of the laminated substrate after the formation of the upper electrode film is not performed, or 2 hours under the temperature condition of 500 ° C., 2 hours under the temperature condition of 600 ° C., and 2 under the temperature condition of 700 ° C. Performed at each condition of time.
Ｔｉ膜、Ｐｔ膜、ＫＮＮ膜、ＲｕＯｘ膜、ＩｒＯｘ膜、ＴｉＯｘ膜の製膜は、いずれも、ＲＦマグネトロンスパッタリング法により行った。 The Ti film, Pt film, KNN film, RuO x film, IrO x film, and TiO x film were all formed by RF magnetron sputtering.
Ｔｉ膜、Ｐｔ膜を製膜する際の処理条件は、それぞれ、下記の通りとした。
基板温度：３００℃
放電パワー：１２００Ｗ
導入ガス：Ａｒガス
Ａｒ雰囲気の圧力：０．３Ｐａ
製膜時間：５分
The processing conditions for forming the Ti film and the Pt film were as follows.
Substrate temperature: 300 ° C
Discharge power: 1200W
Introduced gas: Ar gas Ar atmosphere pressure: 0.3 Pa
Film formation time: 5 minutes
ＫＮＮ膜を製膜する際の処理条件は、下記の通りとした。
基板温度：６００℃
放電パワー：２２００Ｗ
導入ガス：Ａｒ／Ｏ２混合ガス
Ａｒ／Ｏ２混合ガス雰囲気の圧力：０．３Ｐａ
Ａｒガスの分圧／Ｏ２ガスの分圧：２５／１
製膜速度：１μｍ／ｈｒ
The processing conditions for forming the KNN film were as follows.
Substrate temperature: 600 ° C
Discharge power: 2200W
Introduced gas: Ar / O 2 mixed gas Ar / O 2 mixed gas pressure: 0.3 Pa
Ar gas partial pressure / O 2 gas partial pressure: 25/1
Film forming speed: 1 μm / hr
ＲｕＯｘ膜、ＩｒＯｘ膜、ＴｉＯｘ膜を製膜する際の処理条件は、それぞれ、下記の通りとした。
基板温度：室温（２５℃）
放電パワー：３００Ｗ
導入ガス：Ａｒ／Ｏ２混合ガス
Ａｒ＋Ｏ２混合雰囲気の圧力：０．３Ｐａ
Ａｒガスの分圧／Ｏ２ガスの分圧：１／１
製膜速度：０．１μｍ／ｈｒ
The processing conditions for forming the RuO x film, IrO x film, and TiO x film were as follows.
Substrate temperature: Room temperature (25 ° C)
Discharge power: 300W
Introduced gas: Ar / O 2 mixed gas Ar + O 2 mixed atmosphere pressure: 0.3 Pa
Ar gas partial pressure / O 2 gas partial pressure: 1/1
Film forming speed: 0.1 μm / hr
そして、積層基板が有するＫＮＮ膜の寿命、強誘電性をそれぞれ評価した。表１および表２は、ＫＮＮ膜の寿命に関する評価結果を示しており、図５（ａ）〜（ｆ）、図６（ａ）（ｂ）は、それぞれ、ＫＮＮ膜の強誘電性に関する評価結果を示す図であり、電圧−分極量のヒステリシスカーブ、および印加電圧に対する圧電変位特性をそれぞれ示している。 Then, the lifetime and ferroelectricity of the KNN film included in the multilayer substrate were evaluated. Tables 1 and 2 show the evaluation results regarding the lifetime of the KNN film. FIGS. 5A to 5F and 6A and 6B show the evaluation results regarding the ferroelectricity of the KNN film, respectively. FIG. 4 shows a hysteresis curve of voltage-polarization amount and a piezoelectric displacement characteristic with respect to an applied voltage.
（寿命に関する評価）
寿命に関する評価は、上述の実施形態に記載の条件のＨＡＬＴにより、ＫＮＮ膜が絶縁破壊するまでの時間（ｓｅｃ）を測定することで行った。表１、表２中の数値は、１サンプルにつき０．５ｍｍφ内の７箇所で測定した寿命の値の平均値である。また、表１、表２中、「アニールなし」とは上部電極膜の製膜後のアニールを不実施としたことを示し、「６００℃アニール」とは、上部電極膜の製膜後に積層基板を６００℃の温度条件下で２時間アニールしたことを示す。表２中の「５００℃アニール」、「７００℃アニール」の表記も「６００℃アニール」と同様の意味である。
(Evaluation of life)
Evaluation of the lifetime was performed by measuring the time (sec) until the KNN film breaks down by HALT under the conditions described in the above embodiment. The numerical values in Tables 1 and 2 are average values of lifetime values measured at 7 points within 0.5 mmφ per sample. In Tables 1 and 2, “No annealing” indicates that the annealing after the upper electrode film is not formed, and “600 ° C. annealing” indicates the laminated substrate after the upper electrode film is formed. Is annealed at 600 ° C. for 2 hours. In Table 2, “500 ° C. annealing” and “700 ° C. annealing” have the same meaning as “600 ° C. annealing”.
表１に示すように、ＫＮＮ膜と上部電極膜との間に、ＲｕＯｘ膜またはＩｒＯｘ膜を設けた積層基板では、ＫＮＮ膜の寿命が３３００秒以上となることが確認できた。これに対し、ＫＮＮ膜と上部電極膜との間にＴｉＯｘ膜を設けた積層基板では、ＫＮＮ膜の寿命が３３００秒未満となることが確認できた。 As shown in Table 1, it was confirmed that the lifetime of the KNN film was 3300 seconds or longer in the laminated substrate in which the RuO x film or the IrO x film was provided between the KNN film and the upper electrode film. On the other hand, it was confirmed that the lifetime of the KNN film was less than 3300 seconds in the laminated substrate in which the TiO x film was provided between the KNN film and the upper electrode film.
表１、表２に示すように、ＲｕＯｘ膜の膜厚とＩｒＯｘ膜の膜厚とが同じ場合、ＲｕＯｘ膜を設けた積層基板の方が、ＩｒＯｘ膜を設けた積層基板よりも、ＫＮＮ膜の寿命が長くなることが確認できた。 As shown in Tables 1 and 2, when the film thickness of the RuO x film and the film thickness of the IrO x film are the same, the laminated substrate provided with the RuO x film is more than the laminated substrate provided with the IrO x film. It was confirmed that the life of the KNN film was prolonged.
表２に示すように、上部電極膜の製膜後のアニールを不実施とした積層基板では、ＫＮＮ膜の寿命が３３００秒以上となることが確認できた。また、上部電極膜の製膜後に６００℃アニール、７００℃アニールを行った積層基板では、ＫＮＮ膜の寿命が３３００秒以上となることが確認できた。これに対し、上部電極膜の製膜後に５００℃アニールを行った積層基板では、ＫＮＮ膜の寿命が３３００秒未満となることが確認できた。 As shown in Table 2, it was confirmed that the life of the KNN film was 3300 seconds or longer in the laminated substrate in which the annealing after the formation of the upper electrode film was not performed. In addition, it was confirmed that the lifetime of the KNN film was 3300 seconds or longer in the multilayer substrate that was annealed at 600 ° C. and 700 ° C. after the upper electrode film was formed. On the other hand, it was confirmed that the lifetime of the KNN film was less than 3300 seconds in the laminated substrate that was annealed at 500 ° C. after the formation of the upper electrode film.
すなわち、ＫＮＮ膜と上部電極膜との間に、ＲｕＯｘ膜またはＩｒＯｘ膜を設けることで、ＴｉＯｘ膜を設ける場合よりも、ＫＮＮ膜の寿命を長くすることができることを確認できた。また、ＲｕＯｘ膜を設けることで、ＩｒＯｘ膜を設ける場合よりも、ＫＮＮ膜の寿命をさらに長くすることができることを確認できた。さらにまた、上部電極膜の製膜後にアニールを行わないか、６００℃以上の温度条件下でアニールを行うことで、ＫＮＮ膜の寿命を確実に長くすることができることを確認できた。 That is, it was confirmed that by providing a RuO x film or an IrO x film between the KNN film and the upper electrode film, the lifetime of the KNN film can be extended as compared with the case of providing a TiO x film. Further, it was confirmed that the lifetime of the KNN film can be further increased by providing the RuO x film as compared with the case of providing the IrO x film. Furthermore, it was confirmed that the lifetime of the KNN film can be reliably increased by performing annealing after the upper electrode film is formed or by performing annealing under a temperature condition of 600 ° C. or higher.
（強誘電性に関する評価）
強誘電性の評価は、ＫＮＮ膜に対して、±１００ｋＶ／ｃｍの電界を１ｋＨｚの周波数で印加して、電圧と分極量との関係を示すヒステリシスカーブを得た。
(Evaluation of ferroelectricity)
The ferroelectricity was evaluated by applying an electric field of ± 100 kV / cm to the KNN film at a frequency of 1 kHz to obtain a hysteresis curve indicating the relationship between the voltage and the polarization amount.
図５（ａ）〜（ｅ）に示すように、ＫＮＮ膜と上部電極膜との間に、ＲｕＯｘ膜またはＩｒＯｘ膜を設けた積層基板では、｜Ｐｍａｘ−｜≧２３μＣ／ｃｍ２であり、｜Ｐｒ−｜≧１４μＣ／ｃｍ２であることを確認できた。これに対し、図５（ｆ）に示すように、ＫＮＮ膜と上部電極膜との間にＴｉ膜を設けた積層基板では、｜Ｐｍａｘ−｜が１７．６μＣ／ｃｍ２であり、｜Ｐｒ−｜が１０．４μＣ／ｃｍ２であることを確認できた。なお、図５（ａ）〜（ｅ）に示す積層基板では、上部電極膜の製膜後にアニールを行っておらず、図５（ｆ）に示す積層基板では５００℃の温度条件下で２時間アニールを行っている。 As shown in FIGS. 5A to 5E, in the laminated substrate in which the RuO x film or the IrO x film is provided between the KNN film and the upper electrode film, | P max− | ≧ 23 μC / cm 2 Yes, it was confirmed that | P r− | ≧ 14 μC / cm 2 . On the other hand, as shown in FIG. 5F, in the laminated substrate in which the Ti film is provided between the KNN film and the upper electrode film, | P max− | is 17.6 μC / cm 2 , and | P It was confirmed that r− | was 10.4 μC / cm 2 . In the multilayer substrate shown in FIGS. 5A to 5E, annealing is not performed after the upper electrode film is formed, and in the multilayer substrate shown in FIG. 5F, the temperature is 500 ° C. for 2 hours. Annealing is performed.
図５（ａ）に示すように、第２密着層として厚さが１０ｎｍのＲｕＯｘ膜を設け、上部電極膜の製膜後にアニールを不実施とした積層基板では、｜Ｐｍａｘ−｜が２３．８μＣ／ｃｍ２であり、｜Ｐｒ−｜が１５．７μＣ／ｃｍ２であった。また、図６（ａ）に示すように、第２密着層として厚さが１０ｎｍのＲｕＯｘ膜を設け、上部電極膜の製膜後に７００℃の温度条件下で２時間アニールを行った積層基板では、｜Ｐｍａｘ−｜が２３．８μＣ／ｃｍ２であり、｜Ｐｒ−｜が１７．９μＣ／ｃｍ２であった。また、図５（ｄ）に示すように、第２密着層として厚さが２０ｎｍのＩｒＯｘ膜を設け、上部電極膜の製膜後にアニールを不実施とした積層基板では、｜Ｐｍａｘ−｜が２４．２μＣ／ｃｍ２であり、｜Ｐｒ−｜が１４．５μＣ／ｃｍ２であった。また、図６（ｂ）に示すように、第２密着層として厚さが２０ｎｍのＩｒＯｘ膜を設け、上部電極膜の製膜後に５００℃の温度条件下で２時間アニールを行った積層基板では、｜Ｐｍａｘ−｜が２４．０μＣ／ｃｍ２であり、｜Ｐｒ−｜が１４．８μＣ／ｃｍ２であった。 As shown in FIG. 5A, in a laminated substrate in which a RuO x film having a thickness of 10 nm is provided as the second adhesion layer and annealing is not performed after the upper electrode film is formed, | P max− | 0.8 μC / cm 2 and | P r− | was 15.7 μC / cm 2 . Further, as shown in FIG. 6A, a laminated substrate in which a RuO x film having a thickness of 10 nm is provided as the second adhesion layer and annealed for 2 hours at 700 ° C. after forming the upper electrode film. in, | P max- | is 23.8μC / cm 2, | P r- | was 17.9μC / cm 2. Further, as shown in FIG. 5D, in a laminated substrate in which an IrO x film having a thickness of 20 nm is provided as the second adhesion layer and annealing is not performed after the upper electrode film is formed, | P max− | Was 24.2 μC / cm 2 and | P r− | was 14.5 μC / cm 2 . Further, as shown in FIG. 6B, a laminated substrate in which an IrO x film having a thickness of 20 nm is provided as the second adhesion layer and annealed for 2 hours at 500 ° C. after the formation of the upper electrode film. Then, | P max− | was 24.0 μC / cm 2 , and | P r− | was 14.8 μC / cm 2 .
すなわち、図５（ａ）と図６（ａ）との比較、図５（ｄ）と図６（ｂ）との比較から、第２密着層としてＲｕＯｘ膜またはＩｒＯｘ膜のいずれの膜を設けた場合であっても、上部電極膜の製膜後にアニールを行った積層基板の｜Ｐｍａｘ−｜、｜Ｐｒ−｜の値は、上部電極膜の製膜後のアニールを不実施とした積層基板の｜Ｐｍａｘ−｜、｜Ｐｒ−｜の値と、殆ど変わらないことを確認できた。すなわち、いずれの場合も、上部電極膜の製膜後に積層基板に対して行うアニールは、ＫＮＮ膜の強誘電性には影響を及ぼさないことを確認できた。 That is, from the comparison between FIG. 5A and FIG. 6A and the comparison between FIG. 5D and FIG. 6B, the RuO x film or the IrO x film is used as the second adhesion layer. Even if it is provided, the values of | P max− | and | P r− | of the laminated substrate annealed after forming the upper electrode film indicate that the annealing after forming the upper electrode film is not performed. It was confirmed that the values of | P max− | and | P r− | That is, in any case, it was confirmed that annealing performed on the laminated substrate after forming the upper electrode film did not affect the ferroelectricity of the KNN film.
＜本発明の好ましい態様＞
以下、本発明の好ましい態様について付記する。
<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.
（付記１）
本発明の一態様によれば、
基板と、前記基板上に製膜された第１電極膜と、前記第１電極膜上に製膜された圧電膜と、を備える、圧電膜を有する積層基板であって、
前記圧電膜上には、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜が形成されている。
(Appendix 1)
According to one aspect of the invention,
A laminated substrate having a piezoelectric film, comprising: a substrate; a first electrode film formed on the substrate; and a piezoelectric film formed on the first electrode film,
An oxide film made of an oxide represented by the composition formula RuO x or IrO x is formed on the piezoelectric film.
（付記２）
付記１の基板であって、好ましくは、
前記基板と前記第１電極膜との間、または前記第１電極膜と前記圧電膜との間の少なくともいずれかには、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜が形成されている。
(Appendix 2)
The substrate of appendix 1, preferably,
Between at least one of the substrate and the first electrode film, or between the first electrode film and the piezoelectric film, an oxide film made of an oxide represented by a composition formula RuO x or IrO x is provided. Is formed.
（付記３）
付記１または２の基板であって、好ましくは、
前記酸化膜は、組成式ＲｕＯｘで表される酸化物からなる膜である。
(Appendix 3)
Supplementary note 1 or 2 substrate, preferably,
The oxide film is a film made of an oxide represented by a composition formula RuO x .
（付記４）
付記１〜３のいずれかの基板であって、好ましくは、
前記酸化膜は、組成式ＲｕＯｘ（０＜ｘ＜２）で表される酸化物からなる膜である。
(Appendix 4)
The substrate according to any one of appendices 1 to 3, preferably,
The oxide film is a film made of an oxide represented by a composition formula RuO x (0 <x <2).
（付記５）
付記１〜３のいずれかの基板であって、好ましくは、
前記酸化膜は、組成式ＲｕＯｘ（２＜ｘ）で表される酸化物からなる膜である。
(Appendix 5)
The substrate according to any one of appendices 1 to 3, preferably,
The oxide film is a film made of an oxide represented by a composition formula RuO x (2 <x).
（付記６）
付記１〜５のいずれかの基板であって、好ましくは、
前記酸化膜の厚さは、２ｎｍ以上３０ｎｍ以下、好ましくは５ｎｍ以上３０ｎｍ以下である。
(Appendix 6)
The substrate according to any one of appendices 1 to 5, preferably,
The oxide film has a thickness of 2 nm to 30 nm, preferably 5 nm to 30 nm.
（付記７）
付記１〜６のいずれかの基板であって、好ましくは、
前記圧電膜は、組成式（Ｋ１−ｙＮａｙ）ＮｂＯ３（０＜ｙ＜１）で表されるペロブスカイト構造のアルカリニオブ酸化物からなる膜である。
(Appendix 7)
The substrate according to any one of appendices 1 to 6, preferably,
The piezoelectric film is a film made of an alkali niobium oxide having a perovskite structure represented by a composition formula (K 1-y Na y ) NbO 3 (0 <y <1).
（付記８）
付記１〜７のいずれかの基板であって、好ましくは、
前記圧電膜は、
飽和分極量（Ｐｍａｘ−）の絶対値が２３μＣ／ｃｍ２以上であり、
残留分極量（Ｐｒ−）の絶対値が１４μＣ／ｃｍ２以上である。
(Appendix 8)
The substrate according to any one of appendices 1 to 7, preferably,
The piezoelectric film is
The absolute value of the saturation polarization amount (P max− ) is 23 μC / cm 2 or more,
The absolute value of the remanent polarization (P r− ) is 14 μC / cm 2 or more.
（付記９）
付記１〜８のいずれかの基板であって、好ましくは、
前記酸化膜は、アニール（熱処理）が行われていない。
(Appendix 9)
The substrate according to any one of appendices 1 to 8, preferably,
The oxide film is not annealed (heat treatment).
（付記１０）
付記１〜８のいずれかの基板であって、好ましくは、
前記酸化膜は、６００℃以上８００℃以下の温度条件下でアニールが行われている。
(Appendix 10)
The substrate according to any one of appendices 1 to 8, preferably,
The oxide film is annealed under a temperature condition of 600 ° C. or higher and 800 ° C. or lower.
（付記１１）
本発明の他の態様によれば、
基板と、前記基板上に製膜された第１電極膜と、前記第１電極膜上に製膜された圧電膜と、を備える、圧電膜を有する積層基板であって、
前記圧電膜は、組成式（Ｋ１−ｙＮａｙ）ＮｂＯ３（０＜ｙ＜１）で表されるペロブスカイト構造のアルカリニオブ酸化物からなる膜であり、
前記圧電膜上に第２電極膜を製膜し、前記積層基板の温度が２００℃となるように加熱した状態で、前記第１電極膜と前記第２電極膜との間に−３００ｋＶ／ｃｍの電界（−６０Ｖの電圧）を印加した際、電界印加開始から前記圧電膜に流れるリーク電流密度が３０ｍＡ／ｃｍ２を超えるまでの時間が３３００秒以上である、圧電膜を有する積層基板が提供される。
(Appendix 11)
According to another aspect of the invention,
A laminated substrate having a piezoelectric film, comprising: a substrate; a first electrode film formed on the substrate; and a piezoelectric film formed on the first electrode film,
The piezoelectric film is a film made of an alkali niobium oxide having a perovskite structure represented by a composition formula (K 1-y Na y ) NbO 3 (0 <y <1),
A second electrode film is formed on the piezoelectric film, and in a state where the temperature of the laminated substrate is heated to 200 ° C., −300 kV / cm between the first electrode film and the second electrode film. A multilayer substrate having a piezoelectric film is provided in which the time from when the electric field is applied (−60 V voltage) until the leakage current density flowing through the piezoelectric film exceeds 30 mA / cm 2 is 3300 seconds or more. Is done.
（付記１２）
付記１１の基板であって、好ましくは、
前記圧電膜上には、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜が形成されている。
(Appendix 12)
The substrate of appendix 11, preferably,
An oxide film made of an oxide represented by the composition formula RuO x or IrO x is formed on the piezoelectric film.
（付記１３）
本発明のさらに他の態様によれば、
基板と、前記基板上に製膜された第１電極膜と、前記第１電極膜上に製膜された圧電膜と、前記圧電膜上に製膜された第２電極膜と、を備え、
前記圧電膜と前記第２電極膜との間には、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜が設けられている圧電膜を有する素子、または、圧電膜を有するデバイスが提供される。
(Appendix 13)
According to yet another aspect of the invention,
A substrate, a first electrode film formed on the substrate, a piezoelectric film formed on the first electrode film, and a second electrode film formed on the piezoelectric film,
An element having a piezoelectric film in which an oxide film made of an oxide represented by a composition formula RuO x or IrO x is provided between the piezoelectric film and the second electrode film, or a device having a piezoelectric film Is provided.
（付記１４）
本発明のさらに他の態様によれば、
基板上に電極膜を製膜する工程と、
前記電極膜上に圧電膜を製膜する工程と、
前記圧電膜上に組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜を製膜する工程と、を備える、圧電膜を有する積層基板の製造方法が提供される。
(Appendix 14)
According to yet another aspect of the invention,
Forming an electrode film on a substrate;
Forming a piezoelectric film on the electrode film;
There is provided a method of manufacturing a multilayer substrate having a piezoelectric film, comprising: forming an oxide film made of an oxide represented by a composition formula RuO x or IrO x on the piezoelectric film.
（付記１５）
付記１４の方法であって、好ましくは、
前記酸化膜を製膜する工程を行った後、前記積層基板をアニールする工程を有しない。
(Appendix 15)
The method of appendix 14, preferably,
After the step of forming the oxide film, there is no step of annealing the laminated substrate.
（付記１６）
付記１４の方法であって、好ましくは、
前記酸化膜を製膜する工程を行った後、６００℃以上、好ましくは６００℃以上８００℃以下の温度条件下で前記積層基板をアニールする工程をさらに有する。
(Appendix 16)
The method of appendix 14, preferably,
After the step of forming the oxide film, the method further includes a step of annealing the laminated substrate under a temperature condition of 600 ° C. or higher, preferably 600 ° C. or higher and 800 ° C. or lower.
１ 基板
３ 圧電膜
７ａ ＲｕＯｘ膜
７ｂ ＩｒＯｘ膜
１０ 積層基板
DESCRIPTION OF SYMBOLS 1 Substrate 3 Piezoelectric film 7a RuO x film 7b IrO x film 10 Multilayer substrate
Claims (9)
前記圧電膜は、組成式（Ｋ１−ｙＮａｙ）ＮｂＯ３（０＜ｙ＜１）で表されるペロブスカイト構造のアルカリニオブ酸化物からなる膜であり、
前記圧電膜上には、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜が設けられており、
前記酸化膜上に第２電極膜を製膜し、前記積層基板の温度が２００℃となるように加熱した状態で、前記第１電極膜と前記第２電極膜との間に−３００ｋＶ／ｃｍの電界を印加した際、電界印加開始から前記圧電膜に流れるリーク電流密度が３０ｍＡ／ｃｍ２を超えるまでの時間が３３００秒以上である、圧電膜を有する積層基板。 A laminated substrate having a piezoelectric film, comprising: a substrate; a first electrode film formed on the substrate; and a piezoelectric film formed on the first electrode film,
The piezoelectric film is a film made of an alkali niobium oxide having a perovskite structure represented by a composition formula (K 1-y Na y ) NbO 3 (0 <y <1),
On the piezoelectric film, an oxide film made of an oxide represented by a composition formula RuO x or IrO x is provided,
A second electrode film is formed on the oxide film, and is heated so that the temperature of the laminated substrate is 200 ° C., and −300 kV / cm between the first electrode film and the second electrode film. A multilayer substrate having a piezoelectric film, wherein the time from when the electric field is applied until the density of leakage current flowing through the piezoelectric film exceeds 30 mA / cm 2 is 3300 seconds or more.
前記圧電膜は、組成式（Ｋ１−ｙＮａｙ）ＮｂＯ３（０＜ｙ＜１）で表されるペロブスカイト構造のアルカリニオブ酸化物からなる膜であり、
前記圧電膜と前記第２電極膜との間には、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜が設けられており、
前記積層基板の温度が２００℃となるように加熱した状態で、前記第１電極膜と前記第２電極膜との間に−３００ｋＶ／ｃｍの電界を印加した際、電界印加開始から前記圧電膜に流れるリーク電流密度が３０ｍＡ／ｃｍ２を超えるまでの時間が３３００秒以上である、圧電膜を有する素子。 A laminate having a substrate, a first electrode film formed on the substrate, a piezoelectric film formed on the first electrode film, and a second electrode film formed on the piezoelectric film Equipped with a substrate,
The piezoelectric film is a film made of an alkali niobium oxide having a perovskite structure represented by a composition formula (K 1-y Na y ) NbO 3 (0 <y <1),
Between the piezoelectric film and the second electrode film, an oxide film made of an oxide represented by a composition formula RuO x or IrO x is provided,
When an electric field of −300 kV / cm is applied between the first electrode film and the second electrode film in a state where the temperature of the multilayer substrate is heated to 200 ° C., the piezoelectric film A device having a piezoelectric film, in which a time until a leakage current density flowing in the substrate exceeds 30 mA / cm 2 is 3300 seconds or more.
前記第１電極膜上に、組成式（Ｋ１−ｙＮａｙ）ＮｂＯ３（０＜ｙ＜１）で表されるペロブスカイト構造のアルカリニオブ酸化物からなる圧電膜を製膜する工程と、
前記圧電膜上に、組成式ＲｕＯｘまたはＩｒＯｘで表される酸化物からなる酸化膜を製膜する工程と、
を行うことで、前記酸化膜上に第２電極膜を製膜し、前記基板と前記第１電極膜と前記圧電膜と前記酸化膜と前記第２電極膜とを有する積層基板の温度が２００℃となるように加熱した状態で、前記第１電極膜と前記第２電極膜との間に−３００ｋＶ／ｃｍの電界を印加した際、電界印加開始から前記圧電膜に流れるリーク電流密度が３０ｍＡ／ｃｍ２を超えるまでの時間を３３００秒以上とする、圧電膜を有する積層基板の製造方法。 Forming a first electrode film on the substrate;
Forming a piezoelectric film made of an alkali niobium oxide having a perovskite structure represented by a composition formula (K 1-y Na y ) NbO 3 (0 <y <1) on the first electrode film;
Forming an oxide film made of an oxide represented by a composition formula RuO x or IrO x on the piezoelectric film;
To form a second electrode film on the oxide film, and the temperature of the laminated substrate having the substrate, the first electrode film, the piezoelectric film, the oxide film, and the second electrode film is 200. When an electric field of −300 kV / cm is applied between the first electrode film and the second electrode film in a state of being heated so as to be at a temperature of 30 ° C., the density of the leak current flowing through the piezoelectric film from the start of the electric field application is 30 mA. A method for producing a laminated substrate having a piezoelectric film, wherein the time until exceeding / cm 2 is 3300 seconds or more.
The method for producing a laminated substrate having a piezoelectric film according to claim 6, wherein in the step of forming the oxide film, a film having a thickness of 5 nm to 30 nm is formed as the oxide film. .
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