WO2023176761A1 - Element, electronic device, electronic apparatus, and system - Google Patents

Element, electronic device, electronic apparatus, and system Download PDF

Info

Publication number
WO2023176761A1
WO2023176761A1 PCT/JP2023/009579 JP2023009579W WO2023176761A1 WO 2023176761 A1 WO2023176761 A1 WO 2023176761A1 JP 2023009579 W JP2023009579 W JP 2023009579W WO 2023176761 A1 WO2023176761 A1 WO 2023176761A1
Authority
WO
WIPO (PCT)
Prior art keywords
surface acoustic
piezoelectric body
electronic device
acoustic wave
piezoelectric
Prior art date
Application number
PCT/JP2023/009579
Other languages
French (fr)
Japanese (ja)
Inventor
健 木島
Original Assignee
株式会社Gaianixx
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社Gaianixx filed Critical 株式会社Gaianixx
Publication of WO2023176761A1 publication Critical patent/WO2023176761A1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/25—Constructional features of resonators using surface acoustic waves
    • 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
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • 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
    • H10N30/40—Piezoelectric or electrostrictive devices with electrical input and electrical output, e.g. functioning as transformers
    • 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

Definitions

  • the present invention relates to elements, electronic devices, electronic equipment, and systems using piezoelectric bodies.
  • a surface acoustic wave (SAW) element which is one type of piezoelectric element, includes an interdigital transducer (IDT) on a piezoelectric substrate such as a quartz substrate.
  • the interdigital electrodes are a pair and are formed on the piezoelectric substrate so that the comb-shaped electrodes face each other without contacting each other.
  • the surface and vicinity of the surface of the piezoelectric substrate on which the interdigital electrode is formed can be vibrated in a frequency band due to the piezoelectric effect and inverse piezoelectric effect of the piezoelectric substrate.
  • Surface acoustic wave elements are widely used in electronic circuits constituting various electronic devices, such as oscillators, bandpass filters, and gyros, depending on the combination and configuration of interdigital electrodes.
  • Ball SAW sensors are useful for increasing sensitivity because they can significantly increase the interaction distance compared to planar sensors by utilizing the phenomenon in which the SAW's natural collimated beam makes multiple rounds.
  • the sensitive film used in the gas sensor increases the attenuation of the SAW, which prevents high sensitivity.
  • SAW devices have many issues and are still unsatisfactory.Furthermore, there are also demands for energy conservation due to environmental issues, etc., and a new SAW element that can solve these issues has been eagerly awaited.
  • An object of the present invention is to provide a surface acoustic wave device that is environmentally friendly and has excellent accuracy, as well as electronic devices, electronic equipment, and systems using the surface acoustic wave device.
  • the piezoelectric material includes a piezoelectric material having a circular or substantially circular shape, and has one or more piezoelectric materials that allow surface acoustic waves to propagate in the circumferential direction or substantially circumferential direction.
  • a reflector is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave in an element in which the interdigital electrode is provided on the piezoelectric body, surprisingly, correction by a phase difference using the Sagnac effect can be achieved.
  • a reflector we succeeded in increasing the sensitivity and saving energy, and discovered that such a device could solve the above-mentioned conventional problems all at once. . Further, after obtaining the above knowledge, the present inventors conducted further studies and completed the present invention.
  • the element according to [1], wherein the piezoelectric body is cylindrical, substantially cylindrical, barrel-shaped, or substantially barrel-shaped.
  • the interdigital electrode includes a SAW generating means for generating the surface acoustic wave and a SAW receiving means for receiving the surface acoustic wave.
  • An electrode for detecting a signal caused by a surface acoustic wave propagated from the interdigital electrode is provided on a surface of the piezoelectric body in the circumferential direction or substantially parallel to the circumferential direction.
  • the piezoelectric body is a single crystal made of a piezoelectric material having a trigonal or hexagonal crystal structure.
  • the surface acoustic wave is configured to propagate on the c-plane of the single crystal.
  • the element of the present invention is a surface acoustic wave element that is environmentally friendly and has excellent precision
  • the electronic device, electronic equipment, and system of the present invention include the surface acoustic wave element that is environmentally friendly and has excellent accuracy.
  • the high precision characteristics of surface wave elements can be demonstrated.
  • FIG. 1 is a diagram schematically showing an example of a preferred embodiment of the element of the present invention.
  • FIG. 2 is a diagram schematically showing an example of a reflector suitably used in the element of the present invention. It is a figure which shows typically an example of another suitable embodiment of the element of this invention.
  • FIG. 3 is a diagram schematically illustrating the propagation direction of surface acoustic waves in the element of the present invention, the perpendicular direction thereof, and corrections using these.
  • 1 is a diagram schematically showing a film forming apparatus suitably used in Examples.
  • the element of the present invention includes a circular or substantially circular piezoelectric body, and one or more interdigital electrodes are provided on the piezoelectric body so that surface acoustic waves can propagate in a circumferential direction or a substantially circumferential direction.
  • the device is characterized in that a reflector is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave.
  • the reflector is not particularly limited as long as it is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave (hereinafter also referred to as "SAW"), and may be a known reflector; In the invention, as shown in FIG. 1, for example, it is preferable that the electrode be located adjacent to the interdigital electrode (hereinafter also referred to as "IDT electrode”) in the propagation direction of the SAW.
  • the reflector may be, for example, an electrode formed in a grid shape, and in the present invention, as shown in FIG. It is preferable to have a plurality of reflective electrode fingers 23 extending between the reflective electrode fingers 21.
  • each reflective electrode finger 23 has a long shape that extends linearly in a direction (D2 direction) perpendicular to the SAW propagation direction with a constant width, and has the same length as each other.
  • the reflective electrode fingers 23 are arranged side by side in the SAW propagation direction.
  • the number of the plurality of reflective electrode fingers 23 is usually set so that the reflectance of the SAW in the mode intended for use is approximately 100% or more.
  • the theoretically necessary minimum number is preferably, for example, several to ten, and the number of reflective electrode fingers 23 is preferably twenty or more.
  • the reflector is usually not electrically connected to the IDT electrode, and may be in an electrically floating state (a state in which no potential is applied from the outside), or may be provided with a reference potential or the like.
  • the reflector may be electrically connected to one of the IDT electrodes, but is preferably in an electrically floating state (a state in which no potential is applied from the outside). .
  • the element includes a SAW generating means for causing the interdigital interdigital electrode to generate the surface acoustic wave and a SAW receiving means for receiving the surface acoustic wave
  • electrodes for detecting signals caused by surface acoustic waves propagated from the interdigital electrodes are provided in a circumferential direction or a plane substantially parallel to the circumferential direction.
  • the signal is not particularly limited as long as it is a signal caused by the surface acoustic wave, and is usually a signal that propagates in a direction perpendicular to the propagation direction of the surface acoustic wave.
  • the SH wave propagates in a direction perpendicular to the propagation direction of the SH wave. According to such a preferable range, the accuracy of correction using the signal can be more easily improved, and a sensor with higher sensitivity can be realized. Further, in the present invention, it is more preferable that two or more of the interdigital electrodes are provided with the reflector in between, as shown in FIG. It is possible to improve the accuracy through correction using , and it is possible to more easily realize a sensor with higher sensitivity.
  • a preferred example of a mode of correction using the signal will be shown.
  • the voltage is applied to the piezoelectric body 3 by the electrode fingers of the interdigital electrodes and propagates along the piezoelectric body 3 in the D1 direction and the D2 direction.
  • a SAW in a predetermined mode is excited.
  • the excited SAW is mechanically reflected by the electrode fingers of the interdigital electrodes 13a, 13b and the reflector 9, and a standing wave is formed with the pitch of the electrode fingers being half a wavelength.
  • the standing wave is converted into an electrical signal having the same frequency as the standing wave, and extracted by the electrode fingers of the interdigital electrode.
  • the reflector 9 causes a strong standing wave in the IDT electrodes 13a, 13b, improving the function as a resonator. is converted into a bulk wave and enters the piezoelectric body 3, and it is now possible to suitably extract signals propagating in the direction perpendicular to the propagation direction of the surface acoustic waves, that is, in the D3 direction, and using these signals. Correction etc. are also possible.
  • the piezoelectric body is not particularly limited as long as it includes a circular or approximately circular piezoelectric body, and may have any shape. It is preferably cylindrical, barrel-shaped, or substantially barrel-shaped. These suitable shapes can also be obtained by processing according to conventional methods.
  • the material of the piezoelectric body is not particularly limited as long as it is made of a piezoelectric material, but in the present invention, it is preferably a piezoelectric material having a trigonal or hexagonal crystal structure. Further, in the present invention, the piezoelectric body is preferably a single crystal, and more preferably a single crystal made of a piezoelectric material having a trigonal or hexagonal crystal structure.
  • the element can be made more environmentally friendly.
  • the piezoelectric body is a single crystal made of a piezoelectric material having a trigonal or hexagonal crystal structure
  • the element is configured such that the surface acoustic wave propagates on the c-plane of the single crystal.
  • an electrode for reading bulk elastic waves propagating on the a-plane or m-plane of the single crystal is provided on the a-plane or m-plane. According to such a preferable range, even higher sensitivity of the element can be easily realized.
  • the piezoelectric body is laminated on a crystal substrate with a buffer layer interposed therebetween by an epitaxial crystal growth method.
  • the buffer layer is not particularly limited as long as it does not impede the object of the present invention, but preferably contains a metal compound containing Hf or Zr, and preferably contains a metal oxide containing Hf or Zr.
  • the metal compound is not particularly limited and may be any known metal compound as long as it does not impede the object of the present invention. It may be an oxide or a nitride.
  • the metal oxide is usually a crystalline metal oxide, but the crystalline metal oxide contains Hf and/or Zr at 50 atomic % or more among the constituent metals, and contains Al, Ti, It is also preferable to contain 0.1 atomic % to 50 atomic % of one or more metals selected from Y and Ce. According to such a preferable mixed crystal, the stress relaxation effect of the buffer layer is improved. Not only that, but also the piezoelectric properties of the piezoelectric body can be improved.
  • the crystal substrate (hereinafter also simply referred to as “substrate”) is not particularly limited, such as the substrate material, as long as it does not impede the purpose of the present invention, and may be any known crystal substrate. It may be an organic compound or an inorganic compound. In the present invention, it is preferable that the crystal substrate contains an inorganic compound. In the present invention, it is preferable that the substrate has crystals on part or all of its surface, and it is preferable that the substrate has crystals on all or part of its main surface on the crystal growth side. More preferably, a crystal substrate having crystals on the entire main surface on the crystal growth side is most preferable.
  • the crystal is not particularly limited as long as it does not impede the purpose of the present invention, and the crystal structure is also not particularly limited, but may be cubic, tetragonal, trigonal, hexagonal, orthorhombic, or monoclinic. It is preferably a trigonal or hexagonal crystal, and more preferably a trigonal or hexagonal crystal.
  • the crystal substrate may have an off-angle, and examples of the off-angle include an off-angle of 0.2° to 12.0°.
  • the "off angle" refers to the angle between the substrate surface and the crystal growth plane.
  • the shape of the substrate is not particularly limited, but is not particularly limited as long as it is plate-shaped and serves as a support for the buffer layer.
  • the substrate is preferably a Si substrate, more preferably a crystalline Si substrate, and (100) Most preferably, it is a crystalline Si substrate oriented in the direction of .
  • the substrate material include, in addition to the Si substrate, one or more metals belonging to Groups 3 to 15 of the periodic table, or oxides of these metals.
  • the shape of the substrate is not particularly limited, and may be approximately circular (for example, circular, oval, etc.) or polygonal (for example, triangular, square, rectangular, pentagonal, hexagonal, heptagonal, etc.). , octagonal, nonagonal, etc.), and various shapes can be suitably used. Further, in the present invention, a large-area substrate can also be used.
  • the crystal substrate has a flat surface, but the quality of crystal growth of the epitaxial film may be improved if the crystal substrate has an uneven shape on part or all of the surface. This is preferable because it can provide better results.
  • the above-mentioned crystal substrate having an uneven shape may be used as long as an uneven part consisting of a recess or a convex part is formed on a part or all of the surface. It is not limited, and it may be an uneven part consisting of a convex part, an uneven part consisting of a concave part, or an uneven part consisting of a convex part and a concave part.
  • the uneven portions may be formed from regular protrusions or recesses, or may be formed from irregular protrusions or recesses.
  • the uneven portions are formed periodically, and more preferably that they are patterned periodically and regularly.
  • the shape of the uneven portion is not particularly limited, and examples thereof include a stripe shape, a dot shape, a mesh shape, or a random shape, but in the present invention, a dot shape or a stripe shape is preferable, and a dot shape is more preferable. .
  • the pattern shape of the uneven portions may be a polygonal shape such as a triangle, a quadrangle (for example, a square, a rectangle, or a trapezoid), a pentagon, or a hexagon.
  • the shape is circular or elliptical.
  • the lattice shape of the dots is a lattice shape such as a square lattice, an orthorhombic lattice, a triangular lattice, a hexagonal lattice, etc., and a triangular lattice shape is used. is more preferable.
  • the cross-sectional shape of the concave portion or convex portion of the uneven portion is not particularly limited, and includes, for example, a U-shape, a U-shape, an inverted U-shape, a wave shape, a triangle, a quadrilateral (for example, a square, a rectangle, a trapezoid, etc.). ), polygons such as pentagons and hexagons.
  • the thickness of the crystal substrate is not particularly limited, but is preferably 50 to 2000 ⁇ m, more preferably 100 to 1000 ⁇ m.
  • FIG. 1 shows an example of a preferred element of the present invention.
  • a buffer layer 2 is formed on a crystal substrate 1 by an epitaxial crystal growth method, and a piezoelectric body 3 is formed on the buffer layer 2.
  • the piezoelectric body 3 is processed into a cylindrical shape, and an interdigital electrode 13 and a reflector 9 are formed on the side surface. Furthermore, a take-out electrode 15 is formed on the upper surface of the piezoelectric body 3 .
  • the extraction electrode 15 is an electrode for detecting a signal caused by a surface acoustic wave propagated from the interdigital electrode, and is a detector for detecting an SH wave or the like propagating in a direction perpendicular to the propagation direction of the surface acoustic wave. It is connected to the.
  • the interdigital electrode 13, the reflector 9, and the extraction electrode may be formed using known means.
  • the piezoelectric effect of the piezoelectric body 3 causes strain on the piezoelectric body between adjacent electrode fingers of the interdigital electrode 13, and a surface wave is excited.
  • the interdigital electrode has electrode fingers arranged periodically, and the surface wave is most strongly excited when the wavelength and the period of the electrode fingers are equal. Since the frequency is determined by the spacing between the electrodes formed on the surface, high frequencies can be easily accommodated by photolithography or the like.
  • the above-mentioned element is suitably used in an electronic device according to a conventional method.
  • various electronic devices can be constructed by connecting the element as a piezoelectric element to a power source or an electric/electronic circuit, mounting it on a circuit board, or packaging it.
  • the electronic device is preferably a piezoelectric device, and can be used, for example, as a piezoelectric device in electronic equipment such as a gyroscope or a motion sensor.
  • an amplifier and a rectifier circuit are connected and packaged, it can be used for various sensors such as magnetic sensors.
  • the electronic device is suitably used in electronic equipment according to a conventional method.
  • the electronic device can be applied to various electronic devices other than those described above, and more specifically includes, for example, a liquid ejection head, a liquid ejection device, a vibration wave motor, an optical device, a vibration device, an imaging device, Suitable examples include piezoelectric acoustic components and audio playback devices, audio recording devices, mobile phones, and various information terminals that include the piezoelectric acoustic components.
  • the electronic device is also applied to a system according to a conventional method, and such a system includes, for example, a sensor system.
  • Example of piezoelectric production After treating the crystal growth side of the Si substrate (100) with RIE and heating it in the presence of oxygen to form a thermal oxide film, the metal of the evaporation source and the Si A single crystal of the crystalline metal oxide was formed on the Si substrate by causing a thermal reaction with oxygen in the oxide film on the substrate. Then, by flowing oxygen, lowering the temperature, and increasing the pressure, a single crystal film of a crystalline metal oxide was formed as the crystal by a vapor deposition method.
  • the conditions of the vapor deposition method during this film formation were as follows. Vapor deposition source: Hf, Zr Voltage: 3.5-4.75V Pressure: 3 ⁇ 10-2 to 6 ⁇ 10-2 Pa Substrate temperature: 450-700°C
  • FIG. 5 shows a vapor deposition apparatus used to form a single crystalline film of a crystalline metal oxide.
  • the film forming apparatus in FIG. 5 includes metal sources 1101a to 1101b, earths 1102a to 1102h, ICP electrodes 1103a to 1103b, cut filters 1104a to 1104b, DC power supplies 1105a to 1105b, RF power supplies 1106a to 1106b, lamps 1107a to 1107b, It includes at least an Ar source 1108, a reactive gas source 1109, a power source 1110, a substrate holder 1111, a substrate 1112, a cut filter 1113, an ICP ring 1114, a vacuum chamber 1115, and a rotating shaft 1116.
  • the ICP electrodes 1103a to 1103b in FIG. 13 have a substantially concave curved shape or a parabolic shape curved toward the center of the substrate 1112.
  • the substrate 1112 is locked onto the substrate holder 1111.
  • the rotation shaft 1116 is rotated using the power supply 1110 and a rotation mechanism (not shown), and the substrate 1112 is rotated.
  • the substrate 112 is heated by lamps 1107a to 1107b, and the inside of the vacuum chamber 1115 is evacuated to a vacuum or reduced pressure by a vacuum pump (not shown).
  • Ar gas is introduced into the vacuum chamber 1115 from the Ar source 1108, and the substrate is The surface of the substrate 1112 is cleaned by forming argon plasma on the substrate 1112.
  • Ar gas is introduced into the vacuum chamber 1115, and a reactive gas is also introduced using the reactive gas source 1109.
  • the lamps 1107a to 1107b which are lamp heaters, are alternately turned on and off to form a crystal growth film of better quality.
  • a metal film of platinum (Pt) was formed as a conductive film on the single crystal film of the crystalline metal oxide by sputtering.
  • the conditions at this time are shown below.
  • PZT film a Pb(Zr 0.52 Ti 0.48 )O 3 film
  • the prepared sol-gel solution was dropped onto the substrate and rotated at 2000 rpm for 1 minute to spin coat (apply) the sol-gel solution onto the substrate, thereby forming a film containing the precursor.
  • the substrate was placed on a hot plate at a temperature of 150°C, and further placed on a hot plate at a temperature of 350°C to evaporate the solvent and dry the film.
  • heat treatment was performed at 650° C. for 3 minutes in an oxygen (O 2 ) atmosphere to oxidize and crystallize the precursor.
  • O 2 oxygen
  • FIG. 3 shows an example of a device that is a preferred embodiment of the present invention.
  • the device of FIG. 3 differs from that of FIG. 1 in that two interdigital electrodes are provided sandwiching the reflector.
  • the device shown in FIG. 3 includes an SH wave detector for detecting the SH wave and a SAW receiver for detecting the SAW.
  • the piezoelectric body 3 is processed into a cylindrical shape, and interdigital electrodes 13a, 13b and a reflector 9 are formed on the side surfaces using known means.
  • a lead-out electrode 15 is formed on the top surface of the piezoelectric body 3 according to a conventional method.
  • the extraction electrode 15 is connected to an SH wave detector 18 that detects SH waves propagating in a direction perpendicular to the propagation direction of the surface acoustic waves.
  • the interdigital electrodes 13a and 13b, the reflector 9, and the extraction electrode may be formed using known means.
  • a voltage is applied to the interdigital electrodes 13a and 13b, the piezoelectric effect of the piezoelectric body 3 causes strain on the piezoelectric body between adjacent electrode fingers of the interdigital electrodes 13a and 13b, and a surface wave is excited.
  • a SAW receiver 19 is connected to the interdigital electrode 13a, and is configured to be able to detect surface acoustic waves propagating within the SAW propagation path.
  • the surface acoustic waves propagate on the surface of the piezoelectric body 3 in the D1 direction and the D2 direction shown in FIG. 4 by the reflector 9, that is, the surface acoustic waves propagate in mutually opposing directions, which causes a phase difference.
  • the reflector 9 extracting the bulk elastic waves generated between the interdigital electrodes 13a, 13b and the reflector 9 and detecting them via the electrode 15, an environment-friendly high-speed radio that uses surface acoustic waves and bulk elastic waves can be realized. Accurate and highly sensitive sensors can be manufactured.
  • the element of the present invention can be applied to various uses, it is particularly suitable for use in piezoelectric sensors, and is applied, for example, to electronic devices for sensor systems.

Abstract

[Problem] To provide a surface acoustic wave element that is environmentally friendly and has superior accuracy, and an electronic device, an electronic apparatus, and a system in which the surface acoustic wave element is used. [Solution] In an element that includes a circular or substantially circular piezoelectric body and one or more interdigital electrodes provided on the piezoelectric body so that a surface acoustic wave can propagate in the circumferential direction or a substantially circumferential direction, the piezoelectric body in the propagation path of the surface acoustic wave is fitted with a reflector, to thereby fabricate a high-accuracy sensor that uses a bulk acoustic wave generated between the surface acoustic wave and piezoelectric body and the reflector.

Description

素子、電子デバイス、電子機器及びシステムElements, electronic devices, electronic equipment and systems
　本発明は、圧電体を用いた素子、電子デバイス、電子機器及びシステムに関する。 The present invention relates to elements, electronic devices, electronic equipment, and systems using piezoelectric bodies.
　圧電素子の一つである弾性表面波（ＳＡＷ：Ｓｕｒｆａｃｅ　Ａｃｏｕｓｔｉｃ　Ｗａｖｅ）素子は、水晶基板などの圧電基板上にすだれ状電極（ＩＤＴ：Ｉｎｔｅｒｄｉｇｉｔａｌ　Ｔｒａｎｓｄｕｃｅｒ）を備えている。すだれ状電極は、一対となっており、櫛型の電極が非接触で対向するように圧電基板上に形成されている。このすだれ状電極に交流電圧を印加することで、圧電基板の有する圧電効果および逆圧電効果により、すだれ状電極が形成されている圧電基板の表面および表面付近を周波数帯で振動させることができる。弾性表面波素子は、すだれ状電極の組合せや構成によって、発振器、帯域フィルタ、ジャイロなど、様々な電子機器を構成する電子回路に幅広く用いられている。 A surface acoustic wave (SAW) element, which is one type of piezoelectric element, includes an interdigital transducer (IDT) on a piezoelectric substrate such as a quartz substrate. The interdigital electrodes are a pair and are formed on the piezoelectric substrate so that the comb-shaped electrodes face each other without contacting each other. By applying an alternating current voltage to this interdigital electrode, the surface and vicinity of the surface of the piezoelectric substrate on which the interdigital electrode is formed can be vibrated in a frequency band due to the piezoelectric effect and inverse piezoelectric effect of the piezoelectric substrate. Surface acoustic wave elements are widely used in electronic circuits constituting various electronic devices, such as oscillators, bandpass filters, and gyros, depending on the combination and configuration of interdigital electrodes.
　また、近年においては、例えば、移動体通信に用いられる携帯端末装置の小型化、軽量化が進むとともに、高い通信品質を実現するために、さらに高い精度を有する弾性波素子が求められており、このような要求に応えるべく、球状ＳＡＷセンサ（ボールＳＡＷセンサ）等が検討されている（特許文献１）。ボールＳＡＷセンサは、ＳＡＷの自然なコリメートビームが多重周回する現象を利用して、相互作用距離を平面型センサよりも著しく増加させることができたため、高感度化に有用である。しかしながら、例えばガスセンサ等に用いる場合には、ガスセンサに用いられる感応膜がＳＡＷの減衰を増加させ、高感度化を妨げることになり、また、高周波特性や高感度化のための補正手法等についてもＳＡＷデバイスには課題が多くあり、まだまだ満足のいくものではなく、さらには環境問題等に対する省エネの要求も加わり、これら課題を解決するような新規ＳＡＷ素子が待ち望まれていた。 In addition, in recent years, for example, as mobile terminal devices used for mobile communications have become smaller and lighter, acoustic wave elements with even higher precision are required in order to achieve high communication quality. In order to meet such demands, spherical SAW sensors (ball SAW sensors) and the like are being considered (Patent Document 1). Ball SAW sensors are useful for increasing sensitivity because they can significantly increase the interaction distance compared to planar sensors by utilizing the phenomenon in which the SAW's natural collimated beam makes multiple rounds. However, when used in a gas sensor, for example, the sensitive film used in the gas sensor increases the attenuation of the SAW, which prevents high sensitivity. SAW devices have many issues and are still unsatisfactory.Furthermore, there are also demands for energy conservation due to environmental issues, etc., and a new SAW element that can solve these issues has been eagerly awaited.
特開２０１４－１１５０８４号公報Japanese Patent Application Publication No. 2014-115084
　本発明は、環境にやさしく、優れた精度を有する弾性表面波素子、並びに前記弾性表面波素子を用いた電子デバイス、電子機器及びシステムを提供することを目的とする。 An object of the present invention is to provide a surface acoustic wave device that is environmentally friendly and has excellent accuracy, as well as electronic devices, electronic equipment, and systems using the surface acoustic wave device.
　本発明者らは、上記目的を達成すべく鋭意検討した結果、円状又は略円状の圧電体を含み、円周方向又は略円周方向に表面弾性波が伝搬可能となるように１以上のすだれ状電極が前記圧電体に設けられている素子に、前記表面弾性波の伝搬経路内となる前記圧電体に反射器を設けると、驚くべきことに、サニャック効果を用いた位相差による補正を容易に利用できることを知見し、さらに、反射器を用いることにより高感度化の省エネにも成功し、このような素子が、上記した従来の問題を一挙に解決できるものであることを見出した。
　また、本発明者らは、上記知見を得た後、さらに検討を重ねて、本発明を完成させるに至った。 As a result of intensive studies to achieve the above object, the present inventors have discovered that the piezoelectric material includes a piezoelectric material having a circular or substantially circular shape, and has one or more piezoelectric materials that allow surface acoustic waves to propagate in the circumferential direction or substantially circumferential direction. When a reflector is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave in an element in which the interdigital electrode is provided on the piezoelectric body, surprisingly, correction by a phase difference using the Sagnac effect can be achieved. Furthermore, by using a reflector, we succeeded in increasing the sensitivity and saving energy, and discovered that such a device could solve the above-mentioned conventional problems all at once. .
Further, after obtaining the above knowledge, the present inventors conducted further studies and completed the present invention.
　すなわち、本発明は、以下の発明に関する。
［１］　円状又は略円状の圧電体を含み、円周方向又は略円周方向に表面弾性波が伝搬可能となるように１以上のすだれ状電極が前記圧電体に設けられている素子であって、前記表面弾性波の伝搬経路内となる前記圧電体に反射器が設けられていることを特徴とする素子。
［２］　前記圧電体が円柱状、略円柱状、樽状又は略樽状である前記［１］記載の素子。
［３］　前記すだれ状電極が前記反射器を挟んで２以上設けられている前記［１］又は［２］に記載の素子。
［４］　前記すだれ状電極が前記弾性表面波を発生させるＳＡＷ発生手段及び前記弾性表面波を受信するＳＡＷ受信手段を備えている前記［１］～［３］のいずれかに記載の素子。
［５］　前記圧電体の前記円周方向又は前記略円周方向に平行となる面に、前記すだれ電極から伝搬される弾性表面波に起因する信号を検出するための電極が設けられている前記［１］～［４］のいずれかに記載の素子。
［６］　前記信号が、前記弾性表面波の伝搬方向に垂直な方向に伝搬するＳＨ波である前記［５］記載の素子。
［７］　前記圧電体が三方晶又は六方晶の結晶構造を有する圧電性材料からなる単結晶である前記［１］～［６］のいずれかに記載の素子。
［８］　前記単結晶のｃ面上に前記弾性表面波が伝搬するように構成されている前記［７］記載の素子。
［９］　さらに、前記単結晶のａ面又はｍ面上を伝搬するバルク弾性波を読み取るための電極が前記ａ面又はｍ面に設けられている前記［７］又は［８］に記載の素子。
［１０］　前記圧電体が、結晶基板上にバッファ層を介してエピタキシャル結晶成長法により積層されている前記［１］～［９］のいずれかに記載の素子。
［１１］　前記バッファ層が、Ｈｆ又はＺｒを含む金属酸化物を含む前記［１０］記載の素子。
［１２］　圧電素子を含む電子デバイスであって、前記圧電素子が前記［１］～［１１］のいずれかに記載の素子であることを特徴とする電子デバイス。
［１３］　センサである前記［１２］記載の電子デバイス。
［１４］　電子デバイスを含む電子機器であって、前記電子デバイスが、前記［１２］又は［１３］に記載の電子デバイスであることを特徴とする電子機器。
［１５］　電子機器を含むシステムであって、前記電子機器が、前記［１４］記載の電子機器であることを特徴とするシステム。 That is, the present invention relates to the following inventions.
[1] An element that includes a circular or approximately circular piezoelectric body, and one or more interdigital electrodes are provided on the piezoelectric body so that surface acoustic waves can propagate in a circumferential direction or a substantially circumferential direction. An element characterized in that a reflector is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave.
[2] The element according to [1], wherein the piezoelectric body is cylindrical, substantially cylindrical, barrel-shaped, or substantially barrel-shaped.
[3] The element according to [1] or [2], wherein two or more of the interdigital electrodes are provided with the reflector interposed therebetween.
[4] The element according to any one of [1] to [3], wherein the interdigital electrode includes a SAW generating means for generating the surface acoustic wave and a SAW receiving means for receiving the surface acoustic wave.
[5] An electrode for detecting a signal caused by a surface acoustic wave propagated from the interdigital electrode is provided on a surface of the piezoelectric body in the circumferential direction or substantially parallel to the circumferential direction. The element according to any one of [1] to [4].
[6] The element according to [5], wherein the signal is an SH wave propagating in a direction perpendicular to the propagation direction of the surface acoustic wave.
[7] The element according to any one of [1] to [6], wherein the piezoelectric body is a single crystal made of a piezoelectric material having a trigonal or hexagonal crystal structure.
[8] The element according to [7], wherein the surface acoustic wave is configured to propagate on the c-plane of the single crystal.
[9] The element according to [7] or [8], further comprising an electrode provided on the a-plane or m-plane for reading bulk elastic waves propagating on the a-plane or m-plane of the single crystal. .
[10] The device according to any one of [1] to [9], wherein the piezoelectric body is laminated on a crystal substrate via a buffer layer by an epitaxial crystal growth method.
[11] The device according to [10], wherein the buffer layer contains a metal oxide containing Hf or Zr.
[12] An electronic device including a piezoelectric element, wherein the piezoelectric element is the element according to any one of [1] to [11] above.
[13] The electronic device according to [12] above, which is a sensor.
[14] An electronic device including an electronic device, wherein the electronic device is the electronic device according to [12] or [13].
[15] A system including an electronic device, wherein the electronic device is the electronic device described in [14] above.
　本発明の素子は、環境にやさしく、優れた精度を有する弾性表面波素子であり、本発明の電子デバイス、電子機器及びシステムは、前記弾性表面波素子を備えており、環境にやさしく、前記弾性表面波素子の高精度特性を発揮することができる。 The element of the present invention is a surface acoustic wave element that is environmentally friendly and has excellent precision, and the electronic device, electronic equipment, and system of the present invention include the surface acoustic wave element that is environmentally friendly and has excellent accuracy. The high precision characteristics of surface wave elements can be demonstrated.
本発明の素子の好適な実施態様の一例を模式的に示す図である。1 is a diagram schematically showing an example of a preferred embodiment of the element of the present invention. 本発明の素子に好適に用いられる反射器の一例を模式的に示す図である。FIG. 2 is a diagram schematically showing an example of a reflector suitably used in the element of the present invention. 本発明の素子の別の好適な実施態様の一例を模式的に示す図である。It is a figure which shows typically an example of another suitable embodiment of the element of this invention. 本発明の素子における弾性表面波の伝搬方向及びその垂直方向並びにこれらを利用した補正等を模式的に説明する図である。FIG. 3 is a diagram schematically illustrating the propagation direction of surface acoustic waves in the element of the present invention, the perpendicular direction thereof, and corrections using these. 実施例において好適に用いられる成膜装置を模式的に示す図である。1 is a diagram schematically showing a film forming apparatus suitably used in Examples.
　本発明の素子は、円状又は略円状の圧電体を含み、円周方向又は略円周方向に表面弾性波が伝搬可能となるように１以上のすだれ状電極が前記圧電体に設けられている素子であって、前記表面弾性波の伝搬経路内となる前記圧電体に反射器が設けられていることを特長とする。 The element of the present invention includes a circular or substantially circular piezoelectric body, and one or more interdigital electrodes are provided on the piezoelectric body so that surface acoustic waves can propagate in a circumferential direction or a substantially circumferential direction. The device is characterized in that a reflector is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave.
　前記反射器は、前記表面弾性波（以下、「ＳＡＷ」ともいう。）の伝搬経路内となる前記圧電体に設けられていれば特に限定されず、公知の反射器であってよいが、本発明においては、例えば図１に示すように、ＳＡＷの伝搬方向において、すだれ状電極（以下「ＩＤＴ電極」ともいう。）と隣り合うように位置しているのが好ましい。前記反射器は、例えば、格子状に形成されている電極等であってよく、本発明においては、図２に示すように、互いに対向する１対の反射バスバー２１と、前記１対の反射バスバー２１間において延びる複数の反射電極指２３とを有しているのが好ましい。 The reflector is not particularly limited as long as it is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave (hereinafter also referred to as "SAW"), and may be a known reflector; In the invention, as shown in FIG. 1, for example, it is preferable that the electrode be located adjacent to the interdigital electrode (hereinafter also referred to as "IDT electrode") in the propagation direction of the SAW. The reflector may be, for example, an electrode formed in a grid shape, and in the present invention, as shown in FIG. It is preferable to have a plurality of reflective electrode fingers 23 extending between the reflective electrode fingers 21.
　図２の反射バスバー２１及び反射電極指２３の形状および寸法は、各反射電極指２３の両端が１対の反射バスバー２１に接続されていることを除いては、基本的に、ＩＤＴ電極のバスバー及び電極指と同様であってよい。例えば、各反射電極指２３は、一定の幅でＳＡＷの伝搬方向に直交する方向（Ｄ２方向）に直線状に延びる長尺形状を有しており、互いに同等の長さであり、これら複数の反射電極指２３は、例えば、ＳＡＷの伝搬方向にそれぞれ並べて配列されている。複数の反射電極指２３の本数は、通常、利用を意図しているモードのＳＡＷの反射率が概ね１００％以上となるように設定されている。その理論的な必要最小限の本数は、例えば、数本～１０本程度が好適な例として挙げられ、反射電極指２３の本数は、好ましくは２０本以上である。 The shapes and dimensions of the reflective busbar 21 and reflective electrode fingers 23 in FIG. and electrode fingers. For example, each reflective electrode finger 23 has a long shape that extends linearly in a direction (D2 direction) perpendicular to the SAW propagation direction with a constant width, and has the same length as each other. For example, the reflective electrode fingers 23 are arranged side by side in the SAW propagation direction. The number of the plurality of reflective electrode fingers 23 is usually set so that the reflectance of the SAW in the mode intended for use is approximately 100% or more. The theoretically necessary minimum number is preferably, for example, several to ten, and the number of reflective electrode fingers 23 is preferably twenty or more.
　前記反射器は、通常、ＩＤＴ電極とは電気的に非接続であり、電気的に浮遊状態（外部から電位が付与されない状態）であってもよいし、基準電位等が付与されてもよい。本発明においては、前記反射器が、ＩＤＴ電極のうちの一方の電極部と電気的に接続されていてもよいが、電気的に浮遊状態（外部から電位が付与されない状態）であるのが好ましい。 The reflector is usually not electrically connected to the IDT electrode, and may be in an electrically floating state (a state in which no potential is applied from the outside), or may be provided with a reference potential or the like. In the present invention, the reflector may be electrically connected to one of the IDT electrodes, but is preferably in an electrically floating state (a state in which no potential is applied from the outside). .
　また、本発明においては、前記素子が、前記すだれ状電極が前記弾性表面波を発生させるＳＡＷ発生手段及び前記弾性表面波を受信するＳＡＷ受信手段を備えているのが好ましく、前記圧電体の前記円周方向又は前記略円周方向に平行となる面に、前記すだれ電極から伝搬される弾性表面波に起因する信号を検出するための電極が設けられているのも好ましい。前記信号は、前記弾性表面波に起因する信号であれば特に限定されず、通常、前記弾性表面波の伝搬方向に垂直な方向に伝搬する信号であるが、本発明においては、前記弾性表面波の伝搬方向に垂直な方向に伝搬するＳＨ波であるのが好ましい。このような好ましい範囲によれば、前記信号を用いた補正による精度をより容易に向上させることができ、より高感度のセンサを実現することができる。また、本発明においては、例えば図３に示すように、前記すだれ状電極が前記反射器を挟んで２以上設けられているのがより好ましく、このように構成することで、さらに一段と、前記信号を用いた補正による精度を向上させることができ、より高感度のセンサをより容易に実現することができる。 Further, in the present invention, it is preferable that the element includes a SAW generating means for causing the interdigital interdigital electrode to generate the surface acoustic wave and a SAW receiving means for receiving the surface acoustic wave, It is also preferable that electrodes for detecting signals caused by surface acoustic waves propagated from the interdigital electrodes are provided in a circumferential direction or a plane substantially parallel to the circumferential direction. The signal is not particularly limited as long as it is a signal caused by the surface acoustic wave, and is usually a signal that propagates in a direction perpendicular to the propagation direction of the surface acoustic wave. It is preferable that the SH wave propagates in a direction perpendicular to the propagation direction of the SH wave. According to such a preferable range, the accuracy of correction using the signal can be more easily improved, and a sensor with higher sensitivity can be realized. Further, in the present invention, it is more preferable that two or more of the interdigital electrodes are provided with the reflector in between, as shown in FIG. It is possible to improve the accuracy through correction using , and it is possible to more easily realize a sensor with higher sensitivity.
　ここで、前記信号を用いた補正の態様の好適な一例を示す。図４に示すように、すだれ状電極１３ａ、１３ｂに電圧が印加されると、すだれ状電極の電極指によって圧電体３に電圧が印加され圧電体３に沿ってＤ１方向及びＤ２方向に伝搬する所定のモードのＳＡＷが励起される。励起されたＳＡＷは、すだれ状電極１３ａ、１３ｂの電極指及び反射器９によって機械的に反射され、電極指のピッチを半波長とする定在波が形成される。定在波は、当該定在波と同一周波数の電気信号に変換され、すだれ状電極の電極指によって取り出される。ここで、回転角速度が加わったＳＡＷの伝搬するＤ１方向の波とＤ２方向の波とに位相差が生じるので、例えば、位相差を表す下記式（１）を利用した補正等が可能となる。
（式中、Ωは角速度を示し、ｋは波数を示し、Ｎは積算回数を示し、Ａは上部面積を示す。） Here, a preferred example of a mode of correction using the signal will be shown. As shown in FIG. 4, when a voltage is applied to the interdigital electrodes 13a and 13b, the voltage is applied to the piezoelectric body 3 by the electrode fingers of the interdigital electrodes and propagates along the piezoelectric body 3 in the D1 direction and the D2 direction. A SAW in a predetermined mode is excited. The excited SAW is mechanically reflected by the electrode fingers of the interdigital electrodes 13a, 13b and the reflector 9, and a standing wave is formed with the pitch of the electrode fingers being half a wavelength. The standing wave is converted into an electrical signal having the same frequency as the standing wave, and extracted by the electrode fingers of the interdigital electrode. Here, since a phase difference occurs between the wave in the D1 direction and the wave in the D2 direction propagated by the SAW to which the rotational angular velocity is applied, it is possible to perform correction using, for example, the following equation (1) expressing the phase difference.
(In the formula, Ω indicates the angular velocity, k indicates the wave number, N indicates the number of integration, and A indicates the upper area.)
　また、反射器９により、ＩＤＴ電極１３ａ、１３ｂにおける定在波が強く立ち、共振子としての機能が向上し、さらに、例えばＩＤＴ電極１３ａ、１３ｂと反射器９との境界において、ＳＡＷの一部がバルク波に変換されて圧電体３内へ入り込むなどして、弾性表面波の伝搬方向に垂直な方向すなわちＤ３方向に伝搬する信号を好適に取り出すことができるようになり、これら信号を利用した補正等も可能となる。 In addition, the reflector 9 causes a strong standing wave in the IDT electrodes 13a, 13b, improving the function as a resonator. is converted into a bulk wave and enters the piezoelectric body 3, and it is now possible to suitably extract signals propagating in the direction perpendicular to the propagation direction of the surface acoustic waves, that is, in the D3 direction, and using these signals. Correction etc. are also possible.
　前記圧電体は、円状又は略円状の圧電体を含んでいれば特に限定されず、どのような形状を有していてもよいが、本発明においては、前記圧電体が円柱状、略円柱状、樽状又は略樽状であるのが好ましい。これら好適な形状は、常法に従い加工して得ることも可能である。前記圧電体の材料も圧電性材料からなるものであれば特に限定されないが、本発明においては、三方晶又は六方晶の結晶構造を有する圧電性材料であるのが好ましい。また、本発明においては、前記圧電体が単結晶であるのが好ましく、三方晶又は六方晶の結晶構造を有する圧電性材料からなる単結晶であるのがより好ましい。このような好ましい範囲によれば、より高感度化を図ることができ、より環境にやさしい素子とすることができる。なお、前記圧電体が、三方晶又は六方晶の結晶構造を有する圧電性材料からなる単結晶である場合には、前記素子は、前記単結晶のｃ面上に前記弾性表面波が伝搬するように構成されているのが好ましく、さらに、前記単結晶のａ面又はｍ面上を伝搬するバルク弾性波を読み取るための電極が前記ａ面又はｍ面に設けられているのも好ましい。このような好ましい範囲によれば、前記素子のさらなる高感度化を容易に実現することができる。 The piezoelectric body is not particularly limited as long as it includes a circular or approximately circular piezoelectric body, and may have any shape. It is preferably cylindrical, barrel-shaped, or substantially barrel-shaped. These suitable shapes can also be obtained by processing according to conventional methods. The material of the piezoelectric body is not particularly limited as long as it is made of a piezoelectric material, but in the present invention, it is preferably a piezoelectric material having a trigonal or hexagonal crystal structure. Further, in the present invention, the piezoelectric body is preferably a single crystal, and more preferably a single crystal made of a piezoelectric material having a trigonal or hexagonal crystal structure. According to such a preferable range, higher sensitivity can be achieved and the element can be made more environmentally friendly. Note that when the piezoelectric body is a single crystal made of a piezoelectric material having a trigonal or hexagonal crystal structure, the element is configured such that the surface acoustic wave propagates on the c-plane of the single crystal. Further, it is preferable that an electrode for reading bulk elastic waves propagating on the a-plane or m-plane of the single crystal is provided on the a-plane or m-plane. According to such a preferable range, even higher sensitivity of the element can be easily realized.
　本発明においては、前記圧電体は、結晶基板上にバッファ層を介してエピタキシャル結晶成長法により積層されているのが好ましい。前記バッファ層は、本発明の目的を阻害しない限り、特に限定されないが、Ｈｆ又はＺｒを含む金属化合物を含むのが好ましく、Ｈｆ又はＺｒを含む金属酸化物を含むのが好ましい。前記金属化合物は、本発明の目的を阻害しない限り特に限定されず公知の金属化合物であってよい。酸化物であってもよく、窒化物であってもよい。前記金属酸化物は、本発明においては、通常、結晶性金属酸化物であるが、前記結晶性金属酸化物が、構成金属中、Ｈｆ及び／又はＺｒを５０原子％以上含み、Ａｌ、Ｔｉ、Ｙ及びＣｅから選ばれる１種又は２種以上の金属を０．１原子％～５０原子％含むのも好ましく、このような好ましい混晶によれば、前記バッファ層の応力緩和効果をより優れたものとするだけでなく、前記圧電体の圧電特性をより優れたものとすることができる。 In the present invention, it is preferable that the piezoelectric body is laminated on a crystal substrate with a buffer layer interposed therebetween by an epitaxial crystal growth method. The buffer layer is not particularly limited as long as it does not impede the object of the present invention, but preferably contains a metal compound containing Hf or Zr, and preferably contains a metal oxide containing Hf or Zr. The metal compound is not particularly limited and may be any known metal compound as long as it does not impede the object of the present invention. It may be an oxide or a nitride. In the present invention, the metal oxide is usually a crystalline metal oxide, but the crystalline metal oxide contains Hf and/or Zr at 50 atomic % or more among the constituent metals, and contains Al, Ti, It is also preferable to contain 0.1 atomic % to 50 atomic % of one or more metals selected from Y and Ce. According to such a preferable mixed crystal, the stress relaxation effect of the buffer layer is improved. Not only that, but also the piezoelectric properties of the piezoelectric body can be improved.
　前記結晶基板（以下、単に「基板」ともいう）は、基板材料等、本発明の目的を阻害しない限り特に限定されず、公知の結晶基板であってよい。有機化合物であってもよいし、無機化合物であってもよい。本発明においては、前記結晶基板が無機化合物を含んでいるのが好ましい。本発明においては、前記基板が、表面の一部または全部に結晶を有するものであるのが好ましく、結晶成長側の主面の全部または一部に結晶を有している結晶基板であるのがより好ましく、結晶成長側の主面の全部に結晶を有している結晶基板であるのが最も好ましい。前記結晶は、本発明の目的を阻害しない限り特に限定されず、結晶構造等も特に限定されないが、立方晶系、正方晶系、三方晶系、六方晶系、斜方晶系又は単斜晶系の結晶であるのが好ましく、三方晶系又は六方晶系の結晶であるのがより好ましい。また、前記結晶基板は、オフ角を有していてもよく、前記オフ角としては、例えば、０．２°～１２．０°のオフ角などが挙げられる。ここで、「オフ角」とは、基板表面と結晶成長面とのなす角度をいう。前記基板形状は、特に限定されないが、板状であって、前記バッファ層の支持体となるものであれば特に限定されない。絶縁体基板であってもよいし、半導体基板であってもよいが、本発明においては、前記基板が、Ｓｉ基板であるのが好ましく、結晶性Ｓｉ基板であるのがより好ましく、（１００）に配向している結晶性Ｓｉ基板であるのが最も好ましい。なお、前記基板材料としては、例えば、Ｓｉ基板の他に周期律表第３族～第１５族に属する１種若しくは２種以上の金属又はこれらの金属の酸化物等が挙げられる。前記基板の形状は、特に限定されず、略円形状（例えば、円形、楕円形など）であってもよいし、多角形状（例えば、３角形、正方形、長方形、５角形、６角形、７角形、８角形、９角形など）であってもよく、様々な形状を好適に用いることができる。また、本発明においては、大面積の基板を用いることもできる。 The crystal substrate (hereinafter also simply referred to as "substrate") is not particularly limited, such as the substrate material, as long as it does not impede the purpose of the present invention, and may be any known crystal substrate. It may be an organic compound or an inorganic compound. In the present invention, it is preferable that the crystal substrate contains an inorganic compound. In the present invention, it is preferable that the substrate has crystals on part or all of its surface, and it is preferable that the substrate has crystals on all or part of its main surface on the crystal growth side. More preferably, a crystal substrate having crystals on the entire main surface on the crystal growth side is most preferable. The crystal is not particularly limited as long as it does not impede the purpose of the present invention, and the crystal structure is also not particularly limited, but may be cubic, tetragonal, trigonal, hexagonal, orthorhombic, or monoclinic. It is preferably a trigonal or hexagonal crystal, and more preferably a trigonal or hexagonal crystal. Further, the crystal substrate may have an off-angle, and examples of the off-angle include an off-angle of 0.2° to 12.0°. Here, the "off angle" refers to the angle between the substrate surface and the crystal growth plane. The shape of the substrate is not particularly limited, but is not particularly limited as long as it is plate-shaped and serves as a support for the buffer layer. Although it may be an insulating substrate or a semiconductor substrate, in the present invention, the substrate is preferably a Si substrate, more preferably a crystalline Si substrate, and (100) Most preferably, it is a crystalline Si substrate oriented in the direction of . In addition, examples of the substrate material include, in addition to the Si substrate, one or more metals belonging to Groups 3 to 15 of the periodic table, or oxides of these metals. The shape of the substrate is not particularly limited, and may be approximately circular (for example, circular, oval, etc.) or polygonal (for example, triangular, square, rectangular, pentagonal, hexagonal, heptagonal, etc.). , octagonal, nonagonal, etc.), and various shapes can be suitably used. Further, in the present invention, a large-area substrate can also be used.
　また、本発明においては、前記結晶基板が平坦面を有するのが好ましいが、前記結晶基板が表面の一部または全部に凹凸形状を有しているのも、前記エピタキシャル膜の結晶成長の品質をより良好なものとし得るので、好ましい。前記の凹凸形状を有する結晶基板は、表面の一部または全部に凹部または凸部からなる凹凸部が形成されていればそれでよく、前記凹凸部は、凸部または凹部からなるものであれば特に限定されず、凸部からなる凹凸部であってもよいし、凹部からなる凹凸部であってもよいし、凸部および凹部からなる凹凸部であってもよい。また、前記凹凸部は、規則的な凸部または凹部から形成されていてもよいし、不規則な凸部または凹部から形成されていてもよい。本発明においては、前記凹凸部が周期的に形成されているのが好ましく、周期的かつ規則的にパターン化されているのがより好ましい。前記凹凸部の形状としては、特に限定されず、例えば、ストライプ状、ドット状、メッシュ状またはランダム状などが挙げられるが、本発明においては、ドット状またはストライプ状が好ましく、ドット状がより好ましい。また、凹凸部が周期的かつ規則的にパターン化されている場合には、前記凹凸部のパターン形状が、三角形、四角形（例えば正方形、長方形若しくは台形等）、五角形若しくは六角形等の多角形状、円状、楕円状などの形状であるのが好ましい。なお、ドット状に凹凸部を形成する場合には、ドットの格子形状を、例えば正方格子、斜方格子、三角格子、六角格子などの格子形状にするのが好ましく、三角格子の格子形状にするのがより好ましい。前記凹凸部の凹部または凸部の断面形状としては、特に限定されないが、例えば、コの字型、Ｕ字型、逆Ｕ字型、波型、または三角形、四角形（例えば正方形、長方形若しくは台形等）、五角形若しくは六角形等の多角形等が挙げられる。なお、前記結晶基板の厚さは、特に限定されないが、好ましくは、５０～２０００μｍであり、より好ましくは１００～１０００μｍである。 Further, in the present invention, it is preferable that the crystal substrate has a flat surface, but the quality of crystal growth of the epitaxial film may be improved if the crystal substrate has an uneven shape on part or all of the surface. This is preferable because it can provide better results. The above-mentioned crystal substrate having an uneven shape may be used as long as an uneven part consisting of a recess or a convex part is formed on a part or all of the surface. It is not limited, and it may be an uneven part consisting of a convex part, an uneven part consisting of a concave part, or an uneven part consisting of a convex part and a concave part. Furthermore, the uneven portions may be formed from regular protrusions or recesses, or may be formed from irregular protrusions or recesses. In the present invention, it is preferable that the uneven portions are formed periodically, and more preferably that they are patterned periodically and regularly. The shape of the uneven portion is not particularly limited, and examples thereof include a stripe shape, a dot shape, a mesh shape, or a random shape, but in the present invention, a dot shape or a stripe shape is preferable, and a dot shape is more preferable. . Further, when the uneven portions are patterned periodically and regularly, the pattern shape of the uneven portions may be a polygonal shape such as a triangle, a quadrangle (for example, a square, a rectangle, or a trapezoid), a pentagon, or a hexagon. Preferably, the shape is circular or elliptical. In addition, when forming uneven portions in the form of dots, it is preferable that the lattice shape of the dots is a lattice shape such as a square lattice, an orthorhombic lattice, a triangular lattice, a hexagonal lattice, etc., and a triangular lattice shape is used. is more preferable. The cross-sectional shape of the concave portion or convex portion of the uneven portion is not particularly limited, and includes, for example, a U-shape, a U-shape, an inverted U-shape, a wave shape, a triangle, a quadrilateral (for example, a square, a rectangle, a trapezoid, etc.). ), polygons such as pentagons and hexagons. The thickness of the crystal substrate is not particularly limited, but is preferably 50 to 2000 μm, more preferably 100 to 1000 μm.
　以下、本発明の好適な態様を、図面を用いて説明するが、本発明はこれら好適な態様に限定されるものではない。 Hereinafter, preferred embodiments of the present invention will be explained using the drawings, but the present invention is not limited to these preferred embodiments.
　図１は、本発明の好適な素子の一例を示す。図１の素子は、結晶基板１上に、バッファ層２がエピタキシャル結晶成長法により形成されており、前記バッファ層２上には、圧電体３が形成されている。圧電体３は、円柱状に加工されており、側面には、すだれ状電極１３及び反射器９が形成されている。また、圧電体３の上面には、取り出し電極１５が形成されている。取り出し電極１５は、前記すだれ電極から伝搬される弾性表面波に起因する信号を検出するための電極であり、前記弾性表面波の伝搬方向に垂直な方向に伝搬するＳＨ波等を検出する検出器に接続されている。なお、すだれ状電極１３及び反射器９並びに取り出し電極の形成は、それぞれ公知の手段を用いて行われてよい。すだれ状電極１３に電圧が印加されると、圧電体３の圧電効果により、すだれ状電極１３の隣り合う電極指間の圧電体上にひずみが生じ表面波が励振される。すだれ状電極は、電極指が周期的に配置されており、表面波はその波長と電極指周期が等しい場合に最も強く励振される。表面に形成された電極間隔で周波数が決まるため、フォトリソ加工等することにより、容易に高周波に対応することができる。 FIG. 1 shows an example of a preferred element of the present invention. In the device shown in FIG. 1, a buffer layer 2 is formed on a crystal substrate 1 by an epitaxial crystal growth method, and a piezoelectric body 3 is formed on the buffer layer 2. The piezoelectric body 3 is processed into a cylindrical shape, and an interdigital electrode 13 and a reflector 9 are formed on the side surface. Furthermore, a take-out electrode 15 is formed on the upper surface of the piezoelectric body 3 . The extraction electrode 15 is an electrode for detecting a signal caused by a surface acoustic wave propagated from the interdigital electrode, and is a detector for detecting an SH wave or the like propagating in a direction perpendicular to the propagation direction of the surface acoustic wave. It is connected to the. Note that the interdigital electrode 13, the reflector 9, and the extraction electrode may be formed using known means. When a voltage is applied to the interdigital electrode 13, the piezoelectric effect of the piezoelectric body 3 causes strain on the piezoelectric body between adjacent electrode fingers of the interdigital electrode 13, and a surface wave is excited. The interdigital electrode has electrode fingers arranged periodically, and the surface wave is most strongly excited when the wavelength and the period of the electrode fingers are equal. Since the frequency is determined by the spacing between the electrodes formed on the surface, high frequencies can be easily accommodated by photolithography or the like.
　前記素子は、常法に従い、電子デバイスに好適に用いられる。例えば、前記素子を、圧電素子として、電源や電気／電子回路と接続し、回路基板に搭載したり、パッケージしたりすることにより様々な電子デバイスを構成することができる。本発明においては、前記電子デバイスが、圧電デバイスであるのが好ましく、例えば、ジャイロスコープ、モーションセンサ等の電子機器における圧電デバイスとして利用可能である。また、例えば、増幅器と整流回路を接続しパッケージすれば、磁気センサなどの各種センサに利用可能である。 The above-mentioned element is suitably used in an electronic device according to a conventional method. For example, various electronic devices can be constructed by connecting the element as a piezoelectric element to a power source or an electric/electronic circuit, mounting it on a circuit board, or packaging it. In the present invention, the electronic device is preferably a piezoelectric device, and can be used, for example, as a piezoelectric device in electronic equipment such as a gyroscope or a motion sensor. Furthermore, for example, if an amplifier and a rectifier circuit are connected and packaged, it can be used for various sensors such as magnetic sensors.
　前記電子デバイスは、常法に従い電子機器に好適に用いられる。前記電子機器としては、上記した電子機器以外にも様々な電子機器に適用可能であり、より具体的に例えば、液体吐出ヘッド、液体吐出装置、振動波モータ、光学機器、振動装置、撮像装置、圧電音響部品や該圧電音響部品を有する音声再生機器、音声録音機器、携帯電話、各種情報端末等が好適な例として挙げられる。 The electronic device is suitably used in electronic equipment according to a conventional method. The electronic device can be applied to various electronic devices other than those described above, and more specifically includes, for example, a liquid ejection head, a liquid ejection device, a vibration wave motor, an optical device, a vibration device, an imaging device, Suitable examples include piezoelectric acoustic components and audio playback devices, audio recording devices, mobile phones, and various information terminals that include the piezoelectric acoustic components.
　また、前記電子機器は、常法に従いシステムにも適用され、かかるシステムとしては、例えばセンサーシステム等が挙げられる。 Furthermore, the electronic device is also applied to a system according to a conventional method, and such a system includes, for example, a sensor system.
（圧電体の作製例）
　Ｓｉ基板（１００）の結晶成長面側をＲＩＥで処理し、酸素の存在下、加熱して熱酸化膜を形成した後、酸素を用いずに、蒸着法にて、蒸着源の金属と、Ｓｉ基板上の酸化膜中の酸素とを熱反応させ、結晶性金属酸化物の単結晶をＳｉ基板上に形成した。ついで、酸素を流し、温度を下げ、かつ圧力を上げて、蒸着法にて、結晶性金属酸化物の単結晶膜を前記結晶として成膜した。なお、この成膜時の蒸着法の各条件は次の通りであった。
　蒸着源　：　Ｈｆ、Ｚｒ
　電圧　：　３．５～４．７５Ｖ
　圧力　：　３×１０－２～６×１０－２Ｐａ
　基板温度　：　４５０～７００℃ (Example of piezoelectric production)
After treating the crystal growth side of the Si substrate (100) with RIE and heating it in the presence of oxygen to form a thermal oxide film, the metal of the evaporation source and the Si A single crystal of the crystalline metal oxide was formed on the Si substrate by causing a thermal reaction with oxygen in the oxide film on the substrate. Then, by flowing oxygen, lowering the temperature, and increasing the pressure, a single crystal film of a crystalline metal oxide was formed as the crystal by a vapor deposition method. The conditions of the vapor deposition method during this film formation were as follows.
Vapor deposition source: Hf, Zr
Voltage: 3.5-4.75V
Pressure: 3× 10-2 to 6× 10-2 Pa
Substrate temperature: 450-700℃
　結晶性金属酸化物の単結晶膜の成膜に用いた蒸着成膜装置を図５に示す。図５の成膜装置は、ルツボに金属源１１０１ａ～１１０１ｂ、アース１１０２ａ～１１０２ｈ、ＩＣＰ電極１１０３ａ～１１０３ｂ、カットフィルター１１０４ａ～１１０４ｂ、ＤＣ電源１１０５ａ～１１０５ｂ、ＲＦ電源１１０６ａ～１１０６ｂ、ランプ１１０７ａ～１１０７ｂ、Ａｒ源１１０８、反応性ガス源１１０９、電源１１１０、基板ホルダー１１１１、基板１１１２、カットフィルター１１１３、ＩＣＰリング１１１４、真空槽１１１５及び回転軸１１１６を少なくとも備えている。なお、図１３のＩＣＰ電極１１０３ａ～１１０３ｂは基板１１１２の中心側に湾曲した略凹曲面形状又はパラボラ形状を有している。 FIG. 5 shows a vapor deposition apparatus used to form a single crystalline film of a crystalline metal oxide. The film forming apparatus in FIG. 5 includes metal sources 1101a to 1101b, earths 1102a to 1102h, ICP electrodes 1103a to 1103b, cut filters 1104a to 1104b, DC power supplies 1105a to 1105b, RF power supplies 1106a to 1106b, lamps 1107a to 1107b, It includes at least an Ar source 1108, a reactive gas source 1109, a power source 1110, a substrate holder 1111, a substrate 1112, a cut filter 1113, an ICP ring 1114, a vacuum chamber 1115, and a rotating shaft 1116. Note that the ICP electrodes 1103a to 1103b in FIG. 13 have a substantially concave curved shape or a parabolic shape curved toward the center of the substrate 1112.
　図５に示すように、基板１１１２を基板ホルダー１１１１上に係止する。ついで、電源１１１０と回転機構（図示せず）とを用いて回転軸１１１６を回転させ、基板１１１２を回転させる。また、基板１１２をランプ１１０７ａ～１１０７ｂによって加熱し、真空ポンプ（図示せず）によって真空槽１１１５内を排気により真空又は減圧下にする。その後、真空槽１１１５内にＡｒ源１１０８からＡｒガスを導入し、ＤＣ電源１１０５ａ～１１０５ｂ、ＲＦ電源１１０６ａ～１１０６ｂ、ＩＣＰ電極１１０３ａ～１１０３ｂ、カットフィルター１１０４ａ～１１０４ｂ、及びアース１１０２ａ～１１０２ｈを用いて基板１１１２上にアルゴンプラズマを形成することにより、基板１１１２の表面の清浄化を行う。 As shown in FIG. 5, the substrate 1112 is locked onto the substrate holder 1111. Next, the rotation shaft 1116 is rotated using the power supply 1110 and a rotation mechanism (not shown), and the substrate 1112 is rotated. Further, the substrate 112 is heated by lamps 1107a to 1107b, and the inside of the vacuum chamber 1115 is evacuated to a vacuum or reduced pressure by a vacuum pump (not shown). Thereafter, Ar gas is introduced into the vacuum chamber 1115 from the Ar source 1108, and the substrate is The surface of the substrate 1112 is cleaned by forming argon plasma on the substrate 1112.
　真空槽１１１５内にＡｒガスを導入するとともに反応性ガス源１１０９を用いて反応性ガスを導入する。このとき、ランプヒーターであるランプ１１０７ａ～１１０７ｂのオンとオフとを交互に繰り返すことで、より良質な結晶成長膜を形成することができるように構成されている。 Ar gas is introduced into the vacuum chamber 1115, and a reactive gas is also introduced using the reactive gas source 1109. At this time, the lamps 1107a to 1107b, which are lamp heaters, are alternately turned on and off to form a crystal growth film of better quality.
　次に、結晶性金属酸化物の単結晶膜の上に、導電膜として、白金（Ｐｔ）の金属膜をスパッタリング法により形成した。この際の条件を、以下に示す。
　装置　：　ＵＬＶＡＣ社製スパッタリング装置ＱＡＭ－４
　圧力　：　１．２０×１０－１Ｐａ
　ターゲット　：　Ｐｔ
　電力　：　１００Ｗ（ＤＣ）
　厚さ　：　１００ｎｍ
　基板温度　：　４５０～６００℃ Next, a metal film of platinum (Pt) was formed as a conductive film on the single crystal film of the crystalline metal oxide by sputtering. The conditions at this time are shown below.
Equipment: Sputtering equipment QAM-4 manufactured by ULVAC
Pressure: 1.20× 10-1 Pa
Target: Pt
Power: 100W (DC)
Thickness: 100nm
Substrate temperature: 450-600℃
　次に、導電膜上に、ＳＲＯ膜を、スパッタリング法により形成した。この際の条件を、以下に示す。
　装置　：　ＵＬＶＡＣ社製スパッタリング装置ＱＡＭ－４
　パワー　：　１５０Ｗ（ＲＦ）
　ガス　：　Ａｒ
　圧力　：　１．８Ｐａ
　基板温度　：　６００℃
　厚さ　：　２０ｎｍ Next, an SRO film was formed on the conductive film by sputtering. The conditions at this time are shown below.
Equipment: Sputtering equipment QAM-4 manufactured by ULVAC
Power: 150W (RF)
Gas: Ar
Pressure: 1.8Pa
Substrate temperature: 600℃
Thickness: 20nm
 次に、ＳＲＯ膜上に、圧電膜として、Ｐｂ（Ｚｒ０．５２Ｔｉ０．４８）Ｏ３膜（ＰＺＴ膜）を、塗布法により形成した。この際の条件を、以下に示す。 Next, a Pb(Zr 0.52 Ti 0.48 )O 3 film (PZT film) was formed as a piezoelectric film on the SRO film by a coating method. The conditions at this time are shown below.
　Ｐｂの原料として酢酸鉛を用い、Ｚｒの原料として硝酸ジルコニウムを用い、Ｔｉの原料としてチタンイソプロポキシドを用いた。また、Ｐｂ、Ｚｒ及びＴｉの各原料を、Ｐｂ：Ｚｒ：Ｔｉ＝１００＋δ：５２：４８の組成比になるように混合し、溶媒は原料の溶解性を考慮して純水とし、加水分解を制御するため酢酸を添加した。更に、粘度調整用にポリビニルピロリドン粉末を混合溶解させたエタノール（ＰＺＴ１ｍｏｌに対し０．５～３．０ｍｏｌ）を添加して用いた。最後に、塗布時の濡れ性調整用に、２ｎブトキシエタノールを適量混合し、原料溶液としてのゾル・ゲル溶液を調製した。 Lead acetate was used as a raw material for Pb, zirconium nitrate was used as a raw material for Zr, and titanium isopropoxide was used as a raw material for Ti. In addition, Pb, Zr, and Ti raw materials were mixed to have a composition ratio of Pb:Zr:Ti=100+δ:52:48, and the solvent was pure water considering the solubility of the raw materials, and hydrolysis was performed. Acetic acid was added for control. Furthermore, ethanol (0.5 to 3.0 mol per 1 mol of PZT) in which polyvinylpyrrolidone powder was mixed and dissolved was added for viscosity adjustment. Finally, for wettability adjustment during application, an appropriate amount of 2n-butoxyethanol was mixed to prepare a sol-gel solution as a raw material solution.
　次に、調製したゾル・ゲル溶液を、基板上に滴下し、２０００ｒｐｍで１分間回転させ、基板上にゾル・ゲル溶液をスピンコート（塗布）することにより、前駆体を含む膜を形成した。そして、１５０℃の温度のホットプレート上に、基板を載置し、更に３５０℃の温度のホットプレート上に、基板を載置することにより、溶媒を蒸発させて膜を乾燥させた。この工程を５回繰り返して５層を同条件で積層した後、酸素（Ｏ２）雰囲気中、６５０℃で３分間熱処理して前駆体を酸化して結晶化させた。以上のプロセスを１０回繰り返し、Ｐｂ（Ｚｒ０．５２Ｔｉ０．４８）Ｏ３膜（ＰＺＴ膜）を作製した。この時の総膜厚は１０μｍであった。 Next, the prepared sol-gel solution was dropped onto the substrate and rotated at 2000 rpm for 1 minute to spin coat (apply) the sol-gel solution onto the substrate, thereby forming a film containing the precursor. Then, the substrate was placed on a hot plate at a temperature of 150°C, and further placed on a hot plate at a temperature of 350°C to evaporate the solvent and dry the film. After repeating this step five times to stack five layers under the same conditions, heat treatment was performed at 650° C. for 3 minutes in an oxygen (O 2 ) atmosphere to oxidize and crystallize the precursor. The above process was repeated 10 times to produce a Pb(Zr 0.52 Ti 0.48 )O 3 film (PZT film). The total film thickness at this time was 10 μm.
　得られた圧電体の素子への適用例を、以下、図を用いてより具体的に説明するが、本発明は、これら適用例に限定されるものではない。なお、本発明においては、特に断りがない限り、公知の手段を用いて、前記圧電体から素子及び電子デバイス等を製造することができる。 Application examples of the obtained piezoelectric body to elements will be explained in more detail below using the drawings, but the present invention is not limited to these application examples. In the present invention, unless otherwise specified, elements, electronic devices, etc. can be manufactured from the piezoelectric body using known means.
　図３は、本発明の好適な態様である素子の一例を示す。図３の素子は、図１とは、２つのすだれ状電極が前記反射器を挟んで設けられている点で異なる。また、図３の素子は、前記ＳＨ波を検出するためのＳＨ波検出器及びＳＡＷを検出するためのＳＡＷ受信器を備えている。図３の素子は、圧電体３が、円柱状に加工されており、側面には、すだれ状電極１３ａ、１３ｂ及び反射器９が公知の手段を用いて形成されている。また、圧電体３の上面には、取り出し電極１５が常法に従い形成されている。取り出し電極１５は、前記弾性表面波の伝搬方向に垂直な方向に伝搬するＳＨ波を検出するＳＨ波検出器１８に接続されている。なお、すだれ状電極１３ａ、１３ｂ及び反射器９並びに取り出し電極の形成は、それぞれ公知の手段を用いて行われてよい。すだれ状電極１３ａ、１３ｂに電圧が印加されると、圧電体３の圧電効果により、すだれ状電極１３ａ、１３ｂのそれぞれ隣り合う電極指間の圧電体上にひずみが生じ表面波が励振される。また、すだれ状電極１３ａには、ＳＡＷ受信器１９が接続されており、ＳＡＷ伝搬経路内に伝搬する弾性表面波を検出できるように構成されている。弾性表面波は、反射器９により、圧電体３の表面を図４に示すＤ１方向及びＤ２方向にそれぞれ伝搬し、つまり互いに対向する方向に弾性表面波が伝搬し、これにより、位相差が生じるとともに、すだれ状電極１３ａ、１３ｂと反射器９との間等で生じたバルク弾性波を取り出し電極１５を介して検出することにより、弾性表面波とバルク弾性波とを利用する、環境にやさしい高精度かつ高感度のセンサを作製することができる。 FIG. 3 shows an example of a device that is a preferred embodiment of the present invention. The device of FIG. 3 differs from that of FIG. 1 in that two interdigital electrodes are provided sandwiching the reflector. Further, the device shown in FIG. 3 includes an SH wave detector for detecting the SH wave and a SAW receiver for detecting the SAW. In the element shown in FIG. 3, the piezoelectric body 3 is processed into a cylindrical shape, and interdigital electrodes 13a, 13b and a reflector 9 are formed on the side surfaces using known means. Furthermore, a lead-out electrode 15 is formed on the top surface of the piezoelectric body 3 according to a conventional method. The extraction electrode 15 is connected to an SH wave detector 18 that detects SH waves propagating in a direction perpendicular to the propagation direction of the surface acoustic waves. Note that the interdigital electrodes 13a and 13b, the reflector 9, and the extraction electrode may be formed using known means. When a voltage is applied to the interdigital electrodes 13a and 13b, the piezoelectric effect of the piezoelectric body 3 causes strain on the piezoelectric body between adjacent electrode fingers of the interdigital electrodes 13a and 13b, and a surface wave is excited. Further, a SAW receiver 19 is connected to the interdigital electrode 13a, and is configured to be able to detect surface acoustic waves propagating within the SAW propagation path. The surface acoustic waves propagate on the surface of the piezoelectric body 3 in the D1 direction and the D2 direction shown in FIG. 4 by the reflector 9, that is, the surface acoustic waves propagate in mutually opposing directions, which causes a phase difference. At the same time, by extracting the bulk elastic waves generated between the interdigital electrodes 13a, 13b and the reflector 9 and detecting them via the electrode 15, an environment-friendly high-speed radio that uses surface acoustic waves and bulk elastic waves can be realized. Accurate and highly sensitive sensors can be manufactured.
　本発明の素子は、種々の用途に適用可能であるが、特に圧電センサに好適に用いられ、例えばセンサーシステム用の電子デバイス等に適用される。 Although the element of the present invention can be applied to various uses, it is particularly suitable for use in piezoelectric sensors, and is applied, for example, to electronic devices for sensor systems.
　　　１　　結晶基板
　　　２　　バッファ層
　　　３　　圧電体
　　　９　　反射器
　　１０　　素子
　　１３　　すだれ状電極
　　１３ａ　すだれ状電極
　　１３ｂ　すだれ状電極
　　１５　　取り出し電極
　　１８　　ＳＨ波検出器
　　１９　　ＳＡＷ受信器
　　２１　　反射バスバー
　　２３　　反射電極指
１１０１ａ～１０１ｂ　金属源
１１０２ａ～１０２ｊ　アース
１１０３ａ～１０３ｂ　ＩＣＰ電極
１１０４ａ～１０４ｂ　カットフィルター
１１０５ａ～１０５ｂ　ＤＣ電源
１１０６ａ～１０６ｂ　ＲＦ電源
１１０７ａ～１０７ｂ　ランプ
１１０８　　Ａｒ源
１１０９　　反応性ガス源
１１１０　　電源
１１１１　　基板ホルダー
１１１２　　基板
１１１３　　カットフィルター
１１１４　　ＩＣＰリング
１１１５　　真空槽
１１１６　　回転軸
 
  1 Crystal substrate 2 Buffer layer 3 Piezoelectric body 9 Reflector 10 Element 13 Interdigital electrode 13a Interdigital electrode 13b Interdigital electrode 15 Extraction electrode 18 SH wave detector 19 SAW receiver 21 Reflective busbar 23 Reflective electrode fingers 1101a to 101b Metal source 1102a to 102j Earth 1103a to 103b ICP electrodes 1104a to 104b Cut filters 1105a to 105b DC power supplies 1106a to 106b RF power supplies 1107a to 107b Lamps 1108 Ar source 1109 Reactive gas source 1110 Power supply 1111 Substrate holder 1112 Substrate 111 3 Cut filter 1114 ICP ring 1115 Vacuum chamber 1116 Rotating shaft

Claims (15)

  1. 　円状又は略円状の圧電体を含み、円周方向又は略円周方向に表面弾性波が伝搬可能となるように１以上のすだれ状電極が前記圧電体に設けられている素子であって、前記表面弾性波の伝搬経路内となる前記圧電体に反射器が設けられていることを特徴とする素子。 An element including a circular or substantially circular piezoelectric body, and one or more interdigital electrodes are provided on the piezoelectric body so that surface acoustic waves can propagate in a circumferential direction or a substantially circumferential direction. . An element characterized in that a reflector is provided on the piezoelectric body that is within the propagation path of the surface acoustic wave.
  2. 　前記圧電体が円柱状、略円柱状、樽状又は略樽状である請求項１記載の素子。 The element according to claim 1, wherein the piezoelectric body is cylindrical, approximately cylindrical, barrel-shaped, or approximately barrel-shaped.
  3. 　前記すだれ状電極が前記反射器を挟んで２以上設けられている請求項１又は２に記載の素子。 The element according to claim 1 or 2, wherein two or more of the interdigital electrodes are provided with the reflector interposed therebetween.
  4. 　前記すだれ状電極が前記弾性表面波を発生させるＳＡＷ発生手段及び前記弾性表面波を受信するＳＡＷ受信手段を備えている請求項１～３のいずれかに記載の素子。 The element according to any one of claims 1 to 3, wherein the interdigital electrode comprises a SAW generating means for generating the surface acoustic wave and a SAW receiving means for receiving the surface acoustic wave.
  5. 　前記圧電体の前記円周方向又は前記略円周方向に平行となる面に、前記すだれ電極から伝搬される弾性表面波に起因する信号を検出するための電極が設けられている請求項１～４のいずれかに記載の素子。 An electrode for detecting a signal caused by a surface acoustic wave propagated from the interdigital electrode is provided on a surface of the piezoelectric body in the circumferential direction or substantially parallel to the circumferential direction. 4. The device according to any one of 4.
  6. 　前記信号が、前記弾性表面波の伝搬方向に垂直な方向に伝搬するＳＨ波である請求項５記載の素子。 The element according to claim 5, wherein the signal is an SH wave propagating in a direction perpendicular to the propagation direction of the surface acoustic wave.
  7. 　前記圧電体が三方晶又は六方晶の結晶構造を有する圧電性材料からなる単結晶である請求項１～６のいずれかに記載の素子。 The element according to any one of claims 1 to 6, wherein the piezoelectric body is a single crystal made of a piezoelectric material having a trigonal or hexagonal crystal structure.
  8. 　前記単結晶のｃ面上に前記弾性表面波が伝搬するように構成されている請求項７記載の素子。 The element according to claim 7, wherein the surface acoustic wave is configured to propagate on the c-plane of the single crystal.
  9. 　さらに、前記単結晶のａ面又はｍ面上を伝搬するバルク弾性波を読み取るための電極が前記ａ面又はｍ面に設けられている請求項７又は８に記載の素子。 The element according to claim 7 or 8, further comprising an electrode provided on the a-plane or m-plane for reading bulk elastic waves propagating on the a-plane or m-plane of the single crystal.
  10. 　前記圧電体が、結晶基板上にバッファ層を介してエピタキシャル結晶成長法により積層されている請求項１～９のいずれかに記載の素子。 The device according to any one of claims 1 to 9, wherein the piezoelectric body is laminated on a crystal substrate via a buffer layer by an epitaxial crystal growth method.
  11. 　前記バッファ層が、Ｈｆ又はＺｒを含む金属酸化物を含む請求項１０記載の素子。 The device according to claim 10, wherein the buffer layer contains a metal oxide containing Hf or Zr.
  12. 　圧電素子を含む電子デバイスであって、前記圧電素子が請求項１～１１のいずれかに記載の素子であることを特徴とする電子デバイス。 An electronic device comprising a piezoelectric element, wherein the piezoelectric element is the element according to any one of claims 1 to 11.
  13. 　センサである請求項１２記載の電子デバイス。 The electronic device according to claim 12, which is a sensor.
  14. 　電子デバイスを含む電子機器であって、前記電子デバイスが、請求項１２又は１３に記載の電子デバイスであることを特徴とする電子機器。 An electronic device including an electronic device, wherein the electronic device is the electronic device according to claim 12 or 13.
  15. 　電子機器を含むシステムであって、前記電子機器が、請求項１４記載の電子機器であることを特徴とするシステム。
          A system including an electronic device, the electronic device being the electronic device according to claim 14.
PCT/JP2023/009579 2022-03-14 2023-03-13 Element, electronic device, electronic apparatus, and system WO2023176761A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2022038749 2022-03-14
JP2022-038749 2022-03-14
JP2022-138848 2022-08-31
JP2022138848 2022-08-31

Publications (1)

Publication Number Publication Date
WO2023176761A1 true WO2023176761A1 (en) 2023-09-21

Family

ID=88023715

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/009579 WO2023176761A1 (en) 2022-03-14 2023-03-13 Element, electronic device, electronic apparatus, and system

Country Status (2)

Country Link
TW (1) TW202401007A (en)
WO (1) WO2023176761A1 (en)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04242313A (en) * 1991-01-16 1992-08-31 Matsushita Electric Ind Co Ltd Surface acoustic wave device and its manufacture
JP2002026688A (en) * 2000-07-12 2002-01-25 Toppan Printing Co Ltd Spherical surface acoustic wave element
JP2003512637A (en) * 1999-10-15 2003-04-02 トルノワ，ピエ−ル Interface sound filters, especially for wireless connections
JP2004297359A (en) * 2003-03-26 2004-10-21 Seiko Epson Corp Surface acoustic wave device, frequency filter, oscillator, electronic circuit, and electronic apparatus
JP2005159580A (en) * 2003-11-21 2005-06-16 Toppan Printing Co Ltd Drive measuring method of spherical surface acoustic wave element and electromagnetic wave transmitting/receiving system
JP2006177674A (en) * 2004-12-20 2006-07-06 Toppan Printing Co Ltd Spherical elastic surface wave element, device and method for measuring rotation angle
JP2006275999A (en) * 2005-03-04 2006-10-12 Toppan Printing Co Ltd Surface acoustic wave device and utilization method therefor
JP2008241542A (en) * 2007-03-28 2008-10-09 Toppan Printing Co Ltd Spherical elastic surface wave sensor
JP2014169466A (en) * 2013-03-01 2014-09-18 Yuutekku:Kk Orientation substrate, manufacturing method of oriented film substrate, sputtering device and multi-chamber device

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04242313A (en) * 1991-01-16 1992-08-31 Matsushita Electric Ind Co Ltd Surface acoustic wave device and its manufacture
JP2003512637A (en) * 1999-10-15 2003-04-02 トルノワ，ピエ−ル Interface sound filters, especially for wireless connections
JP2002026688A (en) * 2000-07-12 2002-01-25 Toppan Printing Co Ltd Spherical surface acoustic wave element
JP2004297359A (en) * 2003-03-26 2004-10-21 Seiko Epson Corp Surface acoustic wave device, frequency filter, oscillator, electronic circuit, and electronic apparatus
JP2005159580A (en) * 2003-11-21 2005-06-16 Toppan Printing Co Ltd Drive measuring method of spherical surface acoustic wave element and electromagnetic wave transmitting/receiving system
JP2006177674A (en) * 2004-12-20 2006-07-06 Toppan Printing Co Ltd Spherical elastic surface wave element, device and method for measuring rotation angle
JP2006275999A (en) * 2005-03-04 2006-10-12 Toppan Printing Co Ltd Surface acoustic wave device and utilization method therefor
JP2008241542A (en) * 2007-03-28 2008-10-09 Toppan Printing Co Ltd Spherical elastic surface wave sensor
JP2014169466A (en) * 2013-03-01 2014-09-18 Yuutekku:Kk Orientation substrate, manufacturing method of oriented film substrate, sputtering device and multi-chamber device

Also Published As

Publication number Publication date
TW202401007A (en) 2024-01-01

Similar Documents

Publication Publication Date Title
US6348754B1 (en) Surface acoustic wave device and method of manufacturing the same
JP5413386B2 (en) Liquid ejecting head and recording apparatus provided with the same
JP5056914B2 (en) Piezoelectric thin film element and piezoelectric thin film device
JP2007184513A (en) Piezoelectric laminate, surface acoustic wave device, thin-film piezoelectric resonator, and piezoelectric actuator
JPS61177900A (en) Piezo-electric element and its manufacture
JPH0583067A (en) Surface acoustic wave element
WO2023176761A1 (en) Element, electronic device, electronic apparatus, and system
JPH06317465A (en) Pyroelectric infrared detector and fabrication thereof
JP2023134334A (en) Element, electronic device, electronic instrument, and system
JP5007973B2 (en) Thin film manufacturing method
US20220385267A1 (en) Surface acoustic wave device with high electromechanical coupling coefficient based on double-layer electrodes and preparation method thereof
CN113676147A (en) Composite substrate for surface acoustic wave device and method of manufacturing the same
JP3932458B2 (en) Thin film manufacturing method
KR101116061B1 (en) Surface acoustic wave device
JPH10209794A (en) Piezoelectric thin-film resonator
JP2834355B2 (en) Method of manufacturing ferroelectric thin film construct
JPH11122073A (en) Surface acoustic wave element
JP2002151754A (en) Piezoelectric thin film element and its manufacturing method
JPH10200369A (en) Piezoelectric thin film resonator
JP2003034592A (en) Diamond substrate with piezoelectric thin film formed thereon and method of manufacturing the same
JP2718414B2 (en) Method for producing lead titanate thin film
JPH0236608A (en) Frequency adjusting method for surface acoustic wave element
JPH0894436A (en) Pyroelectric infrared detector and its manufacture
JPS6367809A (en) Surface acoustic wave resonator
TW202406178A (en) Electrode, laminated structure, electronic device, electronic instrument, and methods of manufacturing the same

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: 23770716

Country of ref document: EP

Kind code of ref document: A1