WO2018008651A1 - Film piézoélectrique, son procédé de production et composant piézoélectrique utilisant un film piézoélectrique - Google Patents

Film piézoélectrique, son procédé de production et composant piézoélectrique utilisant un film piézoélectrique Download PDF

Info

Publication number
WO2018008651A1
WO2018008651A1 PCT/JP2017/024547 JP2017024547W WO2018008651A1 WO 2018008651 A1 WO2018008651 A1 WO 2018008651A1 JP 2017024547 W JP2017024547 W JP 2017024547W WO 2018008651 A1 WO2018008651 A1 WO 2018008651A1
Authority
WO
WIPO (PCT)
Prior art keywords
piezoelectric
thin film
piezoelectric film
atoms
piezoelectric thin
Prior art date
Application number
PCT/JP2017/024547
Other languages
English (en)
Japanese (ja)
Inventor
孝昭 水野
圭一 梅田
淳史 本多
康弘 會田
雅人 上原
秋山　守人
長瀬　智美
浩志 山田
Original Assignee
株式会社村田製作所
国立研究開発法人産業技術総合研究所
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 株式会社村田製作所, 国立研究開発法人産業技術総合研究所 filed Critical 株式会社村田製作所
Priority to JP2018526400A priority Critical patent/JP6698159B2/ja
Publication of WO2018008651A1 publication Critical patent/WO2018008651A1/fr

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
    • H10N30/074—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
    • H10N30/076—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing by vapour phase deposition
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/853—Ceramic compositions
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron

Definitions

  • the present invention relates to a piezoelectric film, a manufacturing method thereof, and a piezoelectric component using the piezoelectric film.
  • Devices using a piezoelectric body having a piezoelectric effect and a reverse piezoelectric effect are used in a wide range of fields, and their use is expanding in communication devices and the like that require power saving.
  • An example thereof is a MEMS device.
  • Examples of piezoelectric materials used in MEMS devices include GaN (gallium nitride), AlN (aluminum nitride), and ZnO (zinc oxide).
  • GaN gallium nitride
  • AlN aluminum nitride
  • ZnO zinc oxide
  • Non-Patent Document 2 discloses that adding Yb (ytterbium) to a GaN piezoelectric film by sputtering improves the piezoelectricity of the GaN piezoelectric film.
  • Non-Patent Document 3 discloses an AlN piezoelectric film. It is disclosed that the piezoelectric constant of the AlN piezoelectric film is improved by adding Sc (scandium).
  • Non-Patent Documents 1 to 3 the mechanism for improving the piezoelectric constant has not been elucidated, and the elements added to the piezoelectric film are limited. Furthermore, in the conventional research, the GaN piezoelectric film has not obtained sufficient piezoelectricity, and has room for improvement.
  • the present invention has been made in view of such circumstances, and an object thereof is to improve the piezoelectric constant in a GaN piezoelectric film.
  • a piezoelectric film according to one aspect of the present invention is a piezoelectric film made of a gallium nitride crystal having a wurtzite structure, and the gallium nitride crystal contains at least one of trivalent transition metal elements, and is contained in the gallium nitride crystal. In which a part of the gallium atoms is substituted with the trivalent transition metal element.
  • the piezoelectric constant can be improved in the GaN piezoelectric film.
  • surface which shows an experimental condition and an evaluation result. 10 is a graph showing the relationship between the ratio of the c-axis lattice constant to the a-axis lattice constant and the piezoelectric constant d33.
  • FIG. 1 is a plan view schematically showing an example of a piezoelectric device 10 (an example of a piezoelectric component) according to the first embodiment of the present invention.
  • the piezoelectric device 10 is a MEMS vibrator manufactured using MEMS technology, and vibrates in the plane within the XY plane in the orthogonal coordinate system of FIG.
  • the piezoelectric film according to the present invention is not limited to a MEMS vibrator that vibrates in a plane, and may be used for a thickness longitudinal vibrator or the like.
  • the piezoelectric device 10 includes a vibrating part 120, a holding part 140, and a holding arm 110.
  • the vibrating unit 120 has a rectangular outline that extends in a plane along the XY plane.
  • the vibration unit 120 is provided inside the holding unit 140 with a predetermined gap from the holding unit 140. That is, a space is formed between the vibrating unit 120 and the holding unit 140 at a predetermined interval.
  • the holding part 140 is formed in a rectangular frame shape so as to surround the outer edge of the vibration part 120 along the XY plane.
  • the holding part 140 is integrally formed from a prismatic frame.
  • maintenance part 140 should just be provided in at least one part of the circumference
  • the holding arm 110 is provided between the vibrating unit 120 and the holding unit 140, and connects the vibrating unit 120 and the holding unit 140.
  • FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG.
  • the vibration unit 120 has a structure in which a lower electrode E1, a piezoelectric thin film F2 (an example of a piezoelectric film), and an upper electrode E2 are stacked on a substrate F1.
  • the substrate F1 includes an oxidized Si (silicon) layer F11 and an Si layer F12.
  • the oxidized Si layer F11 is a layer of SiO 2 having a thickness of about 400 nm, for example.
  • the Si layer F12 is made of degenerate n-type Si having a thickness of about 10 ⁇ m and a resistivity of about 1 m ⁇ ⁇ cm (concentration 7 ⁇ 10 19 / cm 3 ), for example.
  • the Si layer F12 can contain P (phosphorus), As (arsenic), Sb (antimony), or the like as an n-type dopant.
  • the lower electrode E1 and the upper electrode E2 are formed using a metal material such as Ti (titanium), Al (aluminum), Au (gold), and the like.
  • the thicknesses of the lower electrode E1 and the upper electrode E2 are, for example, about 100 nm.
  • Hf of the lower electrode E1 may be formed on another metal film such as Ti, Al, or Au. Thereby, since the specific resistance is low, the wiring resistance can be reduced.
  • a seed layer of about 20 nm made of, for example, Ti (titanium) or AlN (aluminum nitride) may be provided between the Si layer F12 and the lower electrode E1.
  • the piezoelectric thin film F2 is a thin film having piezoelectricity that converts an applied voltage into vibration.
  • the thickness of the piezoelectric thin film F2 is, for example, about 1000 nm.
  • the piezoelectric thin film F2 expands and contracts in the in-plane direction of the XY plane according to the electric field applied to the piezoelectric thin film F2 by the lower electrode E1 and the upper electrode E2. Due to the expansion and contraction of the piezoelectric thin film F2, the vibration unit 120 undergoes contour vibration in the Y-axis direction.
  • the piezoelectric thin film F2 is made of a GaN (gallium nitride) crystal having a wurtzite structure.
  • a part of Ga atoms in the GaN crystal is replaced with a predetermined atom (hereinafter also referred to as “substitution atom”.
  • substitution element The element of the substitution atom is also referred to as “substitution element”).
  • the substitution element includes at least one or more of trivalent transition metal elements.
  • the substitution element is at least one of Lu (lutetium), Yb (yttrium), Y (yttrium), Ho (holmium), Dy (dysprosium), and Sc (scandium).
  • the ratio of the number of substitution atoms to the total amount of the number of Ga atoms and the number of substitution atoms (hereinafter also referred to as “ratio of substitution atoms”) is a predetermined value. Is set. Thereby, a piezoelectric thin film having good piezoelectricity can be obtained.
  • the substitution atom is a Lu atom
  • the ratio of the number of Lu atoms to the total amount of Ga atoms and Lu atoms in the piezoelectric thin film F2 (hereinafter also referred to as “Lu atom ratio”) is 0 at. % And less than 50 at%, more preferably 40 at% or more and less than 50 at%.
  • the piezoelectric constant of the piezoelectric thin film F2 can be improved.
  • the piezoelectric thin film F2 can obtain a good electromechanical coupling coefficient.
  • the substitution atom is a Y atom
  • the ratio of the number of Y atoms to the total amount of Ga atoms and Y atoms in the piezoelectric thin film F2 (hereinafter also referred to as “Y atom ratio”).
  • the piezoelectric thin film F2 can improve the piezoelectric constant, and as a result, the piezoelectric thin film F2 can be improved.
  • a good electromechanical coupling coefficient can be obtained.
  • the substitution atom is a Dy atom
  • the ratio of the number of Dy atoms to the total amount of the number of Ga atoms and the number of Dy atoms in the piezoelectric thin film F2 (hereinafter also referred to as “the ratio of Dy atoms”).
  • the piezoelectric thin film F2 can improve the piezoelectric constant. As a result, the piezoelectric thin film F2 can obtain a good electromechanical coupling coefficient.
  • the composition ratio of the piezoelectric thin film F2 of the present embodiment Lu X Ga 1-X N ( 0 ⁇ X ⁇ 0.5), or Y X Ga 1-X N ( 0 ⁇ X ⁇ 0.5), or In the case of Dy X Ga 1-X N (0 ⁇ X ⁇ 0.5), the piezoelectric constant can be improved.
  • a more preferable range of the composition ratio of the piezoelectric thin film F2 is Lu X Ga 1-X N (0.375 ⁇ X ⁇ 0.5) or Y X Ga 1-X N (0.375 ⁇ X ⁇ 0). .5), or Dy X Ga 1-X N (0.375 ⁇ X ⁇ 0.5).
  • the lattice constant of the c-axis is lengthened by doping the piezoelectric thin film F2 with a substitution atom, thereby improving the piezoelectric constant.
  • the ratio c / a of the c-axis length to the a-axis length is preferably set in a range of about 1.54 to about 1.64. In this case, the piezoelectric constant can be further improved in the piezoelectric thin film F2.
  • Ga has a larger ionic radius than Al. Therefore, by using GaN for the piezoelectric constant F2, the number of candidate elements to be added can be increased. Further, when GaN is doped with a substitution element, for example, the rate of change of c / a is smaller than when AlN is doped with Sc, so that the fluctuation of the piezoelectric constant d33 due to doping becomes gentle. For this reason, it is easier to obtain a desired piezoelectric constant d33 when GaN is used for the piezoelectric thin film F2.
  • the piezoelectric thin film F2 is formed on the substrate F1 by sputtering.
  • sputtering method for example, binary sputtering using a single metal of Ga and a single metal of a substitution element as a target, or single sputtering using an alloy of Ga metal and a metal of a substitution element as a target is used. it can.
  • a gas mixture of Ar (argon) gas and nitrogen gas is introduced into the vacuum chamber of the sputtering apparatus.
  • Ar gas is an inert gas for sputtering the target
  • nitrogen gas is a supply source of nitrogen atoms constituting the piezoelectric thin film F2.
  • the ratio of substitution atoms in the piezoelectric thin film F2 can be adjusted by adjusting the power supplied to the target.
  • the piezoelectric thin film F2 is formed on the substrate F1 by performing sputtering as described above.
  • the ratio of substitution atoms in the piezoelectric thin film F2 to be formed can be adjusted by adjusting the composition ratio in the target alloy.
  • the above-mentioned mixed gas is introduced into the vacuum chamber of the sputtering apparatus.
  • the piezoelectric thin film F2 according to the present embodiment is formed on the substrate F1.
  • FIG. 3 is a diagram showing the relationship between the ratio of substitution atoms and the piezoelectric constant (d33) of the piezoelectric thin film F2.
  • simulation was performed using Lu, Y, and Dy as substitution elements.
  • the horizontal axis indicates the ratio of substitution atoms when the substitution elements are Lu, Y, and Dy, respectively.
  • the vertical axis indicates the piezoelectric constant of the piezoelectric thin film F2.
  • the simulation performed the first principle calculation based on the density functional theory.
  • the calculation program is VASP ver.
  • a plane wave having a cutoff energy of 500 eV was used as the basis function using 5.3.5.
  • As a calculation method of the electron correlation / exchange energy a generalized gradient approximation was used, and an atomic potential based on the PAW (Projector augmented wave) method was used as the atomic potential.
  • As the k-point sampling mesh 6 ⁇ 6 ⁇ 4 was used, and the calculation model used was a supercell obtained by expanding wurtzite crystal structure GaN twice in the a, b and c directions. Density functional perturbation theory and finite difference method were used to calculate piezoelectric constant, relative permittivity and elastic constant.
  • the graph indicating the measurement point in a round shape shows the result of Lu X Ga 1-X N using Lu as the substitution element
  • the graph showing the measurement point in the rectangle is Y using Y as the substitution element
  • a graph showing the results of X Ga 1-X N and the measurement points indicated by triangles show the results of Dy X Ga 1-X N using Dy as a substitution element.
  • the piezoelectric constant of the piezoelectric thin film F2 increases gradually as the ratio of substitution atoms increases from zero. That is, it can be understood that the piezoelectric constant of the piezoelectric thin film F2 is improved by replacing Ga atoms with substitution atoms (at least one of Lu atoms, Y atoms, and Dy atoms) in GaN. Further, from the graph of FIG. 3, in the case of Lu X Ga 1-X N, Y X Ga 1-X N, and Dy X Ga 1-X N, when 0.375 ⁇ X ⁇ 0.5, The rate of increase of the piezoelectric constant is large.
  • the ratio of the Lu atom is preferably greater than 0 at% and less than 50 at%, more preferably 37.5 at% or more and less than 50 at%.
  • the piezoelectric thin film F2 can improve the piezoelectric constant.
  • the piezoelectric thin film F2 can obtain a good electromechanical coupling coefficient.
  • this effect is more remarkable when the substitution atom is a Lu atom than when the substitution atom is a Y atom or a Dy atom. This is probably because the ionic radius of the Lu atom is closer to the ionic radius of the Ga atom than the Y atom or the Dy atom.
  • the proportion of the Y atom is preferably larger than 0 at% and smaller than 50 at%, more preferably 37.5 at% or more and smaller than 50 at%.
  • the piezoelectric thin film F2 can improve the piezoelectric constant. As a result, the piezoelectric thin film F2 can obtain a good electromechanical coupling coefficient.
  • the proportion of the Dy atom is preferably greater than 0 at% and less than 50 at%, more preferably 37.5 at% or more and less than 50 at%.
  • the piezoelectric thin film F2 can improve the piezoelectric constant. As a result, the piezoelectric thin film F2 can obtain a good electromechanical coupling coefficient.
  • the composition ratio of the piezoelectric thin film F2 of the present embodiment Lu X Ga 1-X N ( 0 ⁇ X ⁇ 0.5), or Y X Ga 1-X N ( 0 ⁇ X ⁇ 0.5), or
  • Dy X Ga 1-X N (0 ⁇ X ⁇ 0.5) the piezoelectric constant can be improved, and more preferably Lu X Ga 1-X N (0.375 ⁇ X ⁇ 0.5), or Y X Ga 1-X N (0.375 ⁇ X ⁇ 0.5), or Dy X Ga 1-X N (0.375 ⁇ X ⁇ 0.5).
  • FIG. 4A is a graph showing changes in the lattice constant of the a axis
  • FIG. 4B is a graph showing changes in the lattice constant of the c axis
  • FIG. 4C is a graph showing changes in the ratio of the c-axis lattice constant to the a-axis lattice constant.
  • each graph represents the ratio of substitution atoms in the case where the substitution elements are Lu, Y, and Dy, respectively.
  • the vertical axis of each graph represents the a-axis lattice constant in FIG. 4A, the c-axis lattice constant in FIG. 4B, and the ratio of the c-axis lattice constant to the a-axis lattice constant in FIG. 4C. Is shown.
  • the graph indicating the measurement point in a round shape shows the result of Lu X Ga 1-X N using Lu as the substitution element
  • the graph showing the measurement point in the rectangle is Y using Y as the substitution element
  • a graph showing the results of X Ga 1-X N and the measurement points indicated by triangles show the results of Dy X Ga 1-X N using Dy as a substitution element.
  • the lattice constant of the a-axis of the piezoelectric thin film F2 gradually increases as the ratio of substitution atoms is increased from zero. That is, it can be understood that the a-axis of the piezoelectric thin film F2 becomes longer when Ga atoms are substituted with substitution atoms (at least one of Lu atoms, Y atoms, and Dy atoms) in GaN.
  • the c-axis lattice constant of the piezoelectric thin film F2 increases to a certain ratio and decreases from the certain ratio when the ratio of substitution atoms is increased from zero.
  • the ratio of the c-axis lattice constant to the a-axis lattice constant gradually decreases as the ratio of substitution atoms increases.
  • the a-axis lattice constant increases, the c-axis lattice constant increases to a certain ratio, and decreases from the certain ratio.
  • the polarization response to the external electric field of the GaN crystal is increased, and the elastic modulus is decreased. It can be said that Ga atoms and substituted atoms change into a crystal structure that is easy to move.
  • Ga atoms are substituted with substitution atoms, whereby the piezoelectric constant of the piezoelectric thin film F2 is improved.
  • the piezoelectric constant gradually increases as c / a decreases.
  • the ratio of the Lu, Y, and Dy elements is 0.25 at% or more
  • the lattice constant of the a axis increases at an almost constant rate. Therefore, it can be seen that when the ratio of the substituted atoms is 0.25 at% or more, the decrease rate of the value of c / a increases.
  • the substitution element is preferably at least one of trivalent transition metal elements, and more preferably, the substitution element is Lu (lutetium), Y (yttrium), Dy (dysprosium). , And Sc (scandium). Note that the substitution element is not limited to one type, and may be a plurality of types of elements exemplified. With reference to FIG.
  • the experimental result verified about the effect of the piezoelectric thin film F2 which concerns on this embodiment is demonstrated.
  • the piezoelectric thin film F2 was formed for each of the comparative example and the experimental example, and the piezoelectricity and the ratio of substitution atoms (at%) in the formed piezoelectric thin film F2 were measured.
  • the piezoelectric thin film F2 used for verification uses Hf or Ti as the lower electrode E1, and was formed on the lower electrode E1 by binary sputtering of a single metal target of Ga and a single metal target of a substitution element.
  • the film-forming temperature was set to 400 ° C. and the sputtering pressure was set to 0.25 Pa in all verifications.
  • the power applied to the Ga target was 100 W, and the power applied to the substitution element target was adjusted according to the ratio of the substitution element to be doped.
  • Comparative Example 1 to Experimental Example 5 Experimental Example 6A, 6B to Experimental Example 31A, 31B
  • the oxygen amount in the target was set to 1000 ppm
  • Experimental Example 32 to Experimental Example 35 the oxygen amount was changed. And verified.
  • Comparative Example 1 Ti was used for the lower electrode E1, and no substitution atoms were added to the GaN atoms. Based on the piezoelectric constant d33 (1.4) of the piezoelectric thin film F2 at this time, the influence of various conditions on the piezoelectric constant was verified in Experimental Example 1 and later.
  • FIG. 6A is a graph showing the results of Experimental Examples 6A to 31A (in the case of Hf base).
  • the horizontal axis in FIG. 6A indicates the value of c / a
  • the vertical axis indicates the piezoelectric constant d33 of the piezoelectric thin film F2.
  • the broken line is the piezoelectric constant d33 of the piezoelectric thin film in Comparative Example 1.
  • FIG. 6B is a graph (comparison result between Experimental Examples 6A to 10A and Experimental Examples 6B to 10B) showing the effect when the lower electrode E1 is Hf when the substitution element is Lu
  • FIG. 6D is a graph showing the effect when the lower electrode E1 is set to Hf when the substitution element is Y (comparison results between Experimental Examples 11A to 17A and Experimental Examples 11B to 17B).
  • 6E is a graph showing the effect when the lower electrode E1 is set to Hf in the case of Dy (comparison result between Experimental Examples 18A to 23A and Experimental Examples 18B to 23B), and FIG. 6E shows the case where the substitution element is Sc 6 is a graph showing the effect when the lower electrode E1 is set to Hf (comparison results between Experimental Examples 24A to 31A and Experimental Examples 24B to 31B).
  • the horizontal axis indicates the value of c / a
  • the vertical axis indicates the piezoelectric constant d33 of the piezoelectric thin film F2.
  • the measurement points indicated by triangles indicate the case where Hf is used for the lower electrode E1
  • the measurement points indicated by circles indicate the case where Ti is used for the lower electrode E1.
  • 6B to 6E that the piezoelectric constant d33 is further improved when Hf is used for the lower electrode E1.
  • FIG. 6F is a graph showing the results of Experimental Examples 32 to 35.
  • the horizontal axis indicates the oxygen content
  • the vertical axis indicates the piezoelectric constant d33 in the piezoelectric thin film F2. From the graph of FIG. 6F, it can be seen that the piezoelectric constant d33 is improved when the amount of oxygen in the target is 5000 wtppm or less.
  • the piezoelectric thin film F2 has a structure in which a part of Ga atoms in the GaN crystal constituting the piezoelectric thin film F2 is substituted with predetermined substitution atoms, so that the piezoelectricity is improved.
  • the substitution element is preferably at least one of trivalent transition metal elements, and more preferably, the substitution element is at least one of Lu, Y, Dy, and Sc.
  • the ratio c / a of the c-axis length to the a-axis length is set in the range of about 1.54 to about 1.64.
  • the piezoelectric constant can be further improved in the piezoelectric thin film F2.
  • FIG. 7 is a view showing an appearance of the piezoelectric device 20 formed using the piezoelectric thin film F2 according to the first embodiment.
  • the piezoelectric device 20 is a device for configuring a MEMS microphone that converts sound pressure into an electrical signal, and includes a diaphragm 210, a support portion 211, and a piezoelectric portion 212.
  • the piezoelectric device 20 is divided into two by a minute slit 213 having a size of about 1 ⁇ m or less, for example.
  • the diaphragm 210 is a thin film that vibrates due to sound pressure, and is formed of silicon (Si).
  • the diaphragm 210 has a substantially square shape, and the lower portions of a pair of opposing sides 214 and 215 are supported by the support portion 211. That is, the diaphragm 210 has a double-supported beam structure.
  • Si forming the vibration plate 210 is a degenerated n-type Si semiconductor having a resistivity of 1.5 m ⁇ ⁇ cm or less, and has a function as a lower electrode of the piezoelectric portion 212 as described later.
  • the piezoelectric portion 212 is disposed along a portion of the diaphragm 210 that is supported by the support portion 211. In the configuration shown in FIG. 7, the four piezoelectric portions 212 are disposed on the vibration plate 210, but the number of piezoelectric portions 212 is not limited to this. In the configuration shown in FIG. 7, the end of the piezoelectric portion 212 is disposed on the side 214 or the side 215, but the end may be disposed away from the side 214 or the side 215.
  • FIG. 8 is a cross-sectional view of the piezoelectric device 20 taken along the line CC ′ shown in FIG.
  • the support part 211 includes a base body 220 and an insulating layer 221.
  • the base body 220 is formed of, for example, silicon (Si) having a thickness of about 400 nm.
  • the insulating layer 221 is made of, for example, silicon oxide (SiO 2).
  • the diaphragm 210 is formed on the support portion 211 formed in this way.
  • the piezoelectric portion 212 disposed along the portion of the diaphragm 210 supported by the support portion 211 includes a piezoelectric thin film F2, an upper electrode E2, and wirings 222 and 223.
  • the piezoelectric thin film F2 is disposed on the diaphragm 210 so as to vibrate with the vibration of the diaphragm 210.
  • the thickness of the piezoelectric thin film F2 in this embodiment is about 500 nm.
  • the ratio of the width (D) of the vibration portion of the piezoelectric thin film F2 to the distance (C) from the center of the vibration plate 210 to the support portion 211 can be, for example, about 40%.
  • the distance C can be about 300 ⁇ m and the width D can be about 120 ⁇ m.
  • An upper electrode E2 is disposed on the upper side of the piezoelectric thin film F2.
  • the upper electrode E2 can be Al (aluminum) having a thickness of about 50 nm.
  • the upper electrode E2 can have a structure having a tensile stress. By giving the upper electrode E2 a tensile stress, the stress in the piezoelectric portion 212 is corrected, and deformation of the diaphragm 210 can be suppressed.
  • the wiring 222 is electrically connected to the upper electrode E2.
  • the wiring 223 is electrically connected to the lower electrode (the diaphragm 210).
  • the wirings 222 and 223 are formed using, for example, gold (Au), platinum (Pt), titanium (Ti), aluminum (Al), or the like.
  • the thickness of the wirings 222 and 223 is about 700 nm.
  • the piezoelectric thin film F2 vibrates as the diaphragm 210 vibrates due to sound pressure.
  • a voltage corresponding to the vibration of the piezoelectric thin film F ⁇ b> 2 is output via the wirings 222 and 223 of the piezoelectric portion 212.
  • a piezoelectric thin film F2 according to an embodiment of the present invention is a piezoelectric thin film F2 made of a gallium nitride crystal having a wurtzite structure, and the gallium nitride crystal includes at least one of trivalent transition metal elements.
  • the gallium nitride crystal has a structure in which some gallium atoms are substituted with a trivalent transition metal element.
  • the trivalent transition metal element includes at least one of lutetium, yttrium, dysprosium, and scandium.
  • the piezoelectric thin film F2 can improve the piezoelectric constant. As a result, the piezoelectric thin film F2 can obtain a good electromechanical coupling coefficient, and the piezoelectricity is improved.
  • the piezoelectric thin film F2 is preferably formed on the lower electrode E1 mainly composed of Hf. Since Hf is a metal having a lattice constant close to that of GaN, the crystallinity of the piezoelectric thin film F2 formed on the hafnium film E1 can be improved by using Hf for the lower electrode.
  • the ratio of the number of gallium atoms and the total number of lutetium, yttrium, dysprosium, and scandium atoms in the piezoelectric thin film F2 to the number of at least one of lutetium, yttrium, dysprosium, and scandium. Is preferably greater than 0 at% and less than or equal to 50 at%.
  • the piezoelectric thin film F2 can further improve the piezoelectric constant. More preferably, the ratio of the number of atoms is 37.5 at% or more and 50 at% or less. In this case, the piezoelectric thin film F2 can further improve the piezoelectric constant.
  • the piezoelectric device 10 includes the above-described piezoelectric thin film F2. Accordingly, the piezoelectric constant can be improved in the piezoelectric device.
  • a piezoelectric film manufacturing method targets an alloy composed of gallium and a trivalent transition metal element (for example, at least one of lutetium, yttrium, dysprosium, and scandium). Then, the above-described piezoelectric thin film F2 is formed on the substrate F1. Thereby, the piezoelectric thin film F2 having a good piezoelectric constant can be obtained.
  • a trivalent transition metal element for example, at least one of lutetium, yttrium, dysprosium, and scandium.
  • a piezoelectric film manufacturing method uses a target made of gallium and a target made of a trivalent transition metal element (for example, at least one of lutetium, yttrium, dysprosium, and scandium). Then, the above-described piezoelectric thin film F2 is formed on the substrate F1. Thereby, the piezoelectric thin film F2 having a good piezoelectric constant can be obtained.
  • a trivalent transition metal element for example, at least one of lutetium, yttrium, dysprosium, and scandium.
  • the oxygen content in the target composed of a trivalent transition metal element is preferably 5000 wtppm or less.
  • the piezoelectric constant can be further improved in the piezoelectric thin film F2 (or F2).
  • each embodiment described above is for facilitating understanding of the present invention, and is not intended to limit the present invention.
  • the present invention can be changed / improved without departing from the spirit thereof, and the present invention includes equivalents thereof.
  • those obtained by appropriately modifying the design of each embodiment by those skilled in the art are also included in the scope of the present invention as long as they include the features of the present invention.
  • each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate.
  • Each embodiment is an exemplification, and it is needless to say that a partial replacement or combination of configurations shown in different embodiments is possible, and these are also included in the scope of the present invention as long as they include the features of the present invention. .

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Ceramic Engineering (AREA)
  • Physical Vapour Deposition (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

La présente invention améliore la constante piézoélectrique d'un film piézoélectrique de GaN. L'invention porte sur un film piézoélectrique qui est constitué d'un cristal de nitrure de gallium ayant une structure de wurtzite, le cristal de nitrure de gallium contenant au moins un élément de métal de transition trivalent, tout en ayant une structure dans laquelle certains des atomes de gallium dans le cristal de nitrure de gallium sont substitués par l'élément de métal de transition trivalent.
PCT/JP2017/024547 2016-07-05 2017-07-04 Film piézoélectrique, son procédé de production et composant piézoélectrique utilisant un film piézoélectrique WO2018008651A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2018526400A JP6698159B2 (ja) 2016-07-05 2017-07-04 圧電膜及びその製造方法並びに圧電膜を用いた圧電部品

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016133556 2016-07-05
JP2016-133556 2016-07-05

Publications (1)

Publication Number Publication Date
WO2018008651A1 true WO2018008651A1 (fr) 2018-01-11

Family

ID=60912131

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/024547 WO2018008651A1 (fr) 2016-07-05 2017-07-04 Film piézoélectrique, son procédé de production et composant piézoélectrique utilisant un film piézoélectrique

Country Status (2)

Country Link
JP (1) JP6698159B2 (fr)
WO (1) WO2018008651A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110601673A (zh) * 2019-08-12 2019-12-20 清华大学 基于铪系铁电薄膜的声表面波器件及薄膜体声波器件
CN111742421A (zh) * 2018-02-21 2020-10-02 株式会社电装 压电膜、其制造方法、压电膜层叠体、其制造方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002374145A (ja) * 2001-06-15 2002-12-26 Ube Electronics Ltd 圧電薄膜共振子
JP2005109678A (ja) * 2003-09-29 2005-04-21 Matsushita Electric Ind Co Ltd 共振器の製造方法及び共振器

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002374145A (ja) * 2001-06-15 2002-12-26 Ube Electronics Ltd 圧電薄膜共振子
JP2005109678A (ja) * 2003-09-29 2005-04-21 Matsushita Electric Ind Co Ltd 共振器の製造方法及び共振器

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
SUZUKI, MASASHI: "Giant piezoelectricity near phase boundary in rare earth doped GaN thin films", EXTENDED ABSTRACTS OF THE JSAP SPRING MEETING, vol. 60, 11 March 2013 (2013-03-11) *
YANAGITANI TAKAHIKO: "Enhanced piezoelectricity YbGaN films near phase boundary", APPLIED PHYSICS LETTERS, vol. 104, no. 8, 24 February 2014 (2014-02-24), pages 082911 - 1-082911-3, XP012182510, DOI: doi:10.1063/1.4866969 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111742421A (zh) * 2018-02-21 2020-10-02 株式会社电装 压电膜、其制造方法、压电膜层叠体、其制造方法
US20200357976A1 (en) * 2018-02-21 2020-11-12 Denso Corporation Piezoelectric film, method of manufacturing same, piezoelectric film laminated body, and method of manufacturing same
US11785857B2 (en) * 2018-02-21 2023-10-10 Denso Corporation Piezoelectric film, method of manufacturing same, piezoelectric film laminated body, and method of manufacturing same
CN111742421B (zh) * 2018-02-21 2024-04-05 株式会社电装 压电膜、其制造方法、压电膜层叠体、其制造方法
CN110601673A (zh) * 2019-08-12 2019-12-20 清华大学 基于铪系铁电薄膜的声表面波器件及薄膜体声波器件
CN110601673B (zh) * 2019-08-12 2021-08-13 清华大学 基于铪系铁电薄膜的声表面波器件及薄膜体声波器件

Also Published As

Publication number Publication date
JP6698159B2 (ja) 2020-05-27
JPWO2018008651A1 (ja) 2019-05-16

Similar Documents

Publication Publication Date Title
US10965270B2 (en) Piezoelectric thin film and piezoelectric vibrator
US10608162B2 (en) Stacked film, electronic device substrate, electronic device, and method of fabricating stacked film
Molarius et al. Piezoelectric ZnO films by rf sputtering
US9972769B2 (en) Piezoelectric thin film and method for manufacturing the same, and piezoelectric element
WO2015025716A1 (fr) Résonateur piézoélectrique et processus pour sa production
CN111244263B (zh) 压电薄膜元件
US11495726B2 (en) Piezoelectric element, and resonator using piezoelectric element
Mertin et al. Enhanced piezoelectric properties of c-axis textured aluminium scandium nitride thin films with high scandium content: Influence of intrinsic stress and sputtering parameters
WO2018008651A1 (fr) Film piézoélectrique, son procédé de production et composant piézoélectrique utilisant un film piézoélectrique
JP2021520755A (ja) フィルムバルク音響波共振器およびその製造方法
TW202119757A (zh) 體聲波共振器
JP6426061B2 (ja) 積層薄膜構造体の製造方法、積層薄膜構造体及びそれを備えた圧電素子
JP2018056349A (ja) 圧電膜及びその製造方法並びに圧電膜を用いた圧電部品
WO2022130676A1 (fr) Résonateur et dispositif résonant
WO2017149675A1 (fr) Film piézoélectrique, procédé permettant de produire ce dernier et composant piézoélectrique utilisant un film piézoélectrique
CN106797207B (zh) 压电振子以及压电振动装置
US11968902B2 (en) Piezoelectric body and MEMS device using same
JP2009231615A (ja) 圧電素子の製造方法、圧電素子、電子機器
US10211043B2 (en) Stacked film, electronic device substrate, electronic device, and method of fabricating stacked film
JP6973745B2 (ja) Ｐｚｔ薄膜積層体の製造方法
US20210384882A1 (en) Resonance device and method for manufacturing resonance device
JP6998718B2 (ja) 圧電素子、圧電素子の製造方法、及び圧電素子を用いた共振子
TWI765612B (zh) 層疊體、使用了該層疊體的壓電器件、層疊體的製造方法以及壓電器件的製造方法
JP6666994B2 (ja) 圧電素子、及び圧電素子の製造方法
US20210098681A1 (en) Semiconductor structure and method for manufacturing thereof

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: 17824254

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2018526400

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17824254

Country of ref document: EP

Kind code of ref document: A1