WO2021172259A1 - 圧電デバイス - Google Patents
圧電デバイス Download PDFInfo
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- WO2021172259A1 WO2021172259A1 PCT/JP2021/006585 JP2021006585W WO2021172259A1 WO 2021172259 A1 WO2021172259 A1 WO 2021172259A1 JP 2021006585 W JP2021006585 W JP 2021006585W WO 2021172259 A1 WO2021172259 A1 WO 2021172259A1
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- Prior art keywords
- single crystal
- electrode layer
- layer
- lower electrode
- recess
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- 239000013078 crystal Substances 0.000 claims abstract description 72
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 claims description 4
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims description 4
- 230000000149 penetrating effect Effects 0.000 claims description 3
- 239000010453 quartz Substances 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 238000000605 extraction Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 description 21
- 238000004519 manufacturing process Methods 0.000 description 17
- 230000003014 reinforcing effect Effects 0.000 description 13
- 230000005284 excitation Effects 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052804 chromium Inorganic materials 0.000 description 4
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 description 4
- 229910001120 nichrome Inorganic materials 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- 238000005530 etching Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000003491 array Methods 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 238000000708 deep reactive-ion etching Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 238000001020 plasma etching Methods 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 235000012431 wafers Nutrition 0.000 description 2
- 230000004913 activation Effects 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
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- 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
- H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
-
- 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
- H10N30/072—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by laminating or bonding of piezoelectric or electrostrictive bodies
-
- 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
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
-
- 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
- H03H9/02228—Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer
-
- 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
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/173—Air-gaps
-
- 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
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/174—Membranes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
-
- 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
- H10N30/06—Forming electrodes or interconnections, e.g. leads or terminals
-
- 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
- H10N30/08—Shaping or machining of piezoelectric or electrostrictive bodies
- H10N30/085—Shaping or machining of piezoelectric or electrostrictive bodies by machining
- H10N30/086—Shaping or machining of piezoelectric or electrostrictive bodies by machining by polishing or grinding
-
- 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
- H10N30/8542—Alkali metal based oxides, e.g. lithium, sodium or potassium niobates
-
- 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
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
- H10N30/871—Single-layered electrodes of multilayer piezoelectric or electrostrictive devices, e.g. internal electrodes
-
- 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
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
- H10N30/877—Conductive materials
Definitions
- the present invention relates to a piezoelectric device.
- Non-Patent Document 1 As prior documents describing the configuration of piezoelectric devices, "Modeling, Fabrication, and characterization of Piezoelectric Micromachined Ultrasonic Transducer Arrays Based on Cavity SOI Wafers" Y. Lu et al., Journal Microelectromechanical Systems, vol. 24, no. 2015, p.1143-1149. (Non-Patent Document 1).
- the piezoelectric device described in Non-Patent Document 1 includes an SOI substrate having a cavity, a piezoelectric layer arranged at least above the cavity, an upper electrode layer provided above the piezoelectric layer, and a piezoelectric layer. It is provided with a lower electrode layer provided on the opposite side of the upper electrode layer. The lower electrode layer is exposed on the periphery of the SOI substrate.
- Non-Patent Document 1 when a voltage is applied between the upper electrode layer and the lower electrode layer and the piezoelectric layer vibrates, the vibration propagates to the peripheral edge of the piezoelectric device through the lower electrode layer. Therefore, the excitation efficiency of the piezoelectric device is low.
- the present invention has been made in view of the above problems, and an object of the present invention is to provide a piezoelectric device having high excitation efficiency.
- the piezoelectric device based on the present invention includes a base portion and a laminated portion.
- the base includes one main surface and the other main surface located on the opposite side of one main surface, and has a recess formed on one main surface.
- the laminated portion is laminated on one main surface side of the base portion so as to cover the recess from above.
- the laminated portion includes, at least above the recess, a single crystal piezoelectric layer and a pair of electrode layers that apply a voltage to the single crystal piezoelectric layer.
- the lower electrode layer which constitutes at least a part of the pair of electrode layers and extends along the base side of the single crystal piezoelectric layer, is located only in the recess.
- the excitation efficiency of the piezoelectric device can be increased.
- FIG. 5 is a cross-sectional view of the piezoelectric device of FIG. 1 as viewed from the direction of the arrow along line II-II. It is sectional drawing which shows the state which provided the lower electrode layer on the lower surface of the single crystal piezoelectric layer in the manufacturing method of the piezoelectric device which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the state before forming the concave part and the protruding part in the base part in the manufacturing method of the piezoelectric device which concerns on Embodiment 1 of this invention.
- FIG. 5 is a cross-sectional view showing a state in which a base portion is bonded to the lower surface of a single crystal piezoelectric layer in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- FIG. 5 is a cross-sectional view showing a state in which the upper surface of the single crystal piezoelectric layer is scraped in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- FIG. 5 is a cross-sectional view of the piezoelectric device of FIG. 10 as viewed from the direction of the arrow along the XI-XI line.
- FIG. 1 is a plan view showing the configuration of the piezoelectric device according to the first embodiment of the present invention.
- FIG. 2 is a cross-sectional view of the piezoelectric device of FIG. 1 as viewed from the direction of the arrow along line II-II.
- the piezoelectric device 100 includes a base portion 110 and a laminated portion 120.
- the base 110 includes one main surface 111 and the other main surface 112 located on the opposite side of one main surface 111.
- the base 110 has a recess 113 formed on one of the main surfaces 111.
- the outer shape of the recess 113 is circular when viewed from the direction orthogonal to one of the main surfaces 111, but may be elliptical or polygonal.
- the width of the opening located on one main surface 111 side of the recess 113 is narrower than the width of the bottom of the recess 113.
- the width of the opening may be equal to the width of the bottom, and the width of the opening may be wider than the width of the bottom.
- the region located above the opening of the recess 113 may be referred to as above the recess 113.
- the recess 113 is covered from above by the laminated portion 120 laminated on one main surface 111 side of the base 110.
- the inside of the recess 113 is a closed space.
- the pressure inside the recess 113 is a negative pressure.
- the pressure inside the recess 113 may be atmospheric pressure or positive pressure.
- the base 110 is made of Si.
- the material constituting the base 110 is not limited to Si.
- the laminated portion 120 includes a single crystal piezoelectric layer 130 and a pair of electrode layers.
- the pair of electrode layers applies a voltage to the single crystal piezoelectric layer 130.
- the pair of electrode layers is composed of an upper electrode layer 140 and a lower electrode layer 150.
- the single crystal piezoelectric layer 130 is located above the base 110.
- the single crystal piezoelectric layer 130 is arranged so that at least a part of the single crystal piezoelectric layer 130 is located above the recess 113.
- a hole 131 penetrating from one main surface 111 to the other main surface 112 is provided in a portion of the single crystal piezoelectric layer 130 located above the lower electrode layer 150.
- the single crystal piezoelectric layer 130 is composed of lithium tantalate or lithium niobate.
- the single crystal piezoelectric layer 130 composed of lithium tantalate or lithium niobate has a uniform polarization state.
- the single crystal piezoelectric layer 130 may be made of quartz.
- the upper electrode layer 140 is arranged above the single crystal piezoelectric layer 130.
- the upper electrode layer 140 is arranged so that at least a part of the upper electrode layer 140 is located above the recess 113.
- the upper electrode layer 140 is arranged above a part of the single crystal piezoelectric layer 130.
- An adhesion layer made of, for example, Ti, Cr, Ni, NiCr, or the like may be arranged between the upper electrode layer 140 and the single crystal piezoelectric layer 130.
- the upper electrode layer 140 is made of a metal such as Al or Pt.
- the upper electrode layer 140 is connected to the first lead-out wiring 160.
- the first lead-out wiring 160 is connected to the upper surface of the portion of the upper electrode layer 140 located above the base portion 110, and is drawn out along the surface of the single crystal piezoelectric layer 130 opposite to the base portion 110 side.
- the first lead-out wiring 160 is made of a metal such as Au.
- a close contact layer may be formed between the first lead-out wiring 160 and the upper electrode layer 140.
- the adhesion layer is made of, for example, Ti, Cr, Ni or NiCr. Further, the first lead-out wiring 160 and the upper electrode layer 140 are in ohmic contact with each other.
- the lower electrode layer 150 is arranged so as to face at least a part of the upper electrode layer 140 with the single crystal piezoelectric layer 130 interposed therebetween.
- the lower electrode layer 150 constitutes a part of the pair of electrode layers.
- the lower electrode layer 150 extends along the base 110 side of the single crystal piezoelectric layer 130.
- the lower electrode layer 150 is located only in the recess 113.
- the lower electrode layer 150 is arranged above the recess 113 so as to face at least a part of the upper electrode layer 140 with the single crystal piezoelectric layer 130 interposed therebetween.
- a part of the lower electrode layer 150 is arranged so as to be located below the hole 131 formed in the single crystal piezoelectric layer 130.
- the lower electrode layer 150 is formed so as to cover the pores 131 of the single crystal piezoelectric layer 130 from below.
- the lower electrode layer 150 is made of a metal such as Al or Pt.
- the second lead-out wiring 170 electrically connected to the lower electrode layer 150 is provided in the hole 131.
- the second lead-out wiring 170 is connected to the upper surface of the lower electrode layer 150 in the hole 131, covers the inner surface of the hole 131, and is opposite to the base 110 side of the single crystal piezoelectric layer 130. It is pulled out along the surface of.
- the second lead-out wiring 170 is made of a metal such as Au.
- a close contact layer may be formed between the second lead-out wiring 170 and the lower electrode layer 150.
- the adhesion layer is made of, for example, Ti, Cr, Ni or NiCr. Further, the second lead-out wiring 170 and the lower electrode layer 150 are in ohmic contact with each other.
- the lower electrode layer 150 may be formed so as to cover the lower part of the hole 131 of the single crystal piezoelectric layer 130 with an adhesion layer.
- the material of the adhesion layer is not particularly limited as long as it is a material having conductivity and adhesion.
- the adhesion layer is composed of, for example, Ti, Cr, Ni or NiCr.
- the base 110 includes a protrusion 114 protruding into the recess 113 from the bottom of the recess 113.
- the protruding portion 114 does not necessarily have to be provided. As shown in FIG. 2, the depth of the recess 113 is H1, the height of the protrusion 114 from the bottom of the recess 113 is H2, and the relationship of H2 ⁇ H1 is satisfied.
- the protruding portion 114 has a frustum-like shape.
- the cross-sectional area of the protruding portion 114 increases as the distance from the bottom of the recess 113 increases.
- the cross-sectional area may become smaller as the distance from the bottom of the recess 113 increases.
- the cross-sectional area of the protrusion 114 may be constant regardless of the distance from the bottom of the recess 113.
- the entire inside of the hole 131 overlaps with the upper surface 114t of the protrusion 114.
- the area inside the hole 131 is S1
- the area of the upper surface 114t of the protrusion 114 is S2, and the relationship S2 ⁇ S1.
- the reinforcing lower electrode layer 180 is provided between the lower electrode layer 150 and the upper surface 114t of the protruding portion 114.
- the reinforcing lower electrode layer 180 does not necessarily have to be provided.
- the reinforcing lower electrode layer 180 does not necessarily have to have conductivity, and may not be made of metal.
- the thickness of the lower electrode layer 150 of the portion where the voltage is applied to the single crystal piezoelectric layer 130 is t1
- the lower portion of the portion located between the upper surface 114t of the protrusion 114 and the hole 131 is t2
- the relationship of t2> t1 is satisfied.
- a voltage is applied to the single crystal piezoelectric layer 130 at a portion located between the upper surface 114t of the protruding portion 114 and the hole 131. It is thicker than the part to be used.
- a voltage is applied to the single crystal piezoelectric layer 130 at the portion of the lower electrode layer 150 located between the upper surface 114t of the protrusion 114 and the hole 131. Thicker than the part.
- the upper surface 114t of the protrusion 114 is in contact with the lower electrode layer. In the present embodiment, the upper surface 114t of the protrusion 114 is in contact with the reinforcing lower electrode layer 180.
- FIG. 3 is a cross-sectional view showing a state in which a lower electrode layer is provided on the lower surface of the single crystal piezoelectric layer in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- the thickness of the single crystal piezoelectric layer 130 at the time of formation is thicker than the thickness of the single crystal piezoelectric layer 130 finally included in the piezoelectric device 100 according to the present embodiment.
- the lower electrode layer 150 is provided on the lower surface of the single crystal piezoelectric layer 130 by a lift-off method, a plating method, an etching method, or the like.
- the reinforcing lower electrode layer 180 is further provided on a part of the lower surface of the lower electrode layer 150.
- FIG. 4 is a cross-sectional view showing a state before forming a recess and a protrusion at the base in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- FIG. 5 is a cross-sectional view showing a state in which a recess and a protrusion are formed in the base portion in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- a recess 113 and a protrusion are formed in the base 110 by deep reactive ion etching (DRIE) or the like from one main surface 111 side of the base 110 to the base 110.
- DRIE deep reactive ion etching
- FIG. 6 is a cross-sectional view showing a state in which the base portion is bonded to the lower surface of the single crystal piezoelectric layer in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- one main surface 111 of the base 110 is bonded to the lower surface of the single crystal piezoelectric layer 130 by surface activation bonding or atomic diffusion bonding.
- a bonding layer made of Ti or the like may be interposed in the bonding surface.
- the inside of the recess 113 becomes a closed space.
- the reinforcing lower electrode layer 180 and the upper surface 114t of the protruding portion 114 are in contact with each other.
- the reinforcing lower electrode layer 180 and the upper surface 114t of the protruding portion 114 are not joined and can be brought into contact with each other.
- the single crystal piezoelectric layer 130 and the base 110 are joined under vacuum pressure in order to prevent foreign matter from entering the recess 113.
- the vacuum pressure may be any of low vacuum, medium vacuum, high vacuum and ultra high vacuum. Since the single crystal piezoelectric layer 130 and the base 110 are joined in this way, the pressure inside the recess 113 becomes a negative pressure.
- the atmosphere when joining the single crystal piezoelectric layer 130 and the base 110 is not limited to vacuum pressure.
- the single crystal piezoelectric layer 130 may be bonded to the base 110 under atmospheric pressure, or may be bonded to the base 110 under a pressure higher than atmospheric pressure.
- FIG. 7 is a cross-sectional view showing a state in which the upper surface of the single crystal piezoelectric layer is scraped in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- the upper surface of the single crystal piezoelectric layer 130 is shaved by CMP or the like to make the single crystal piezoelectric layer 130 a desired thickness.
- the thickness of the single crystal piezoelectric layer 130 is adjusted so that a desired amount of expansion and contraction of the single crystal piezoelectric layer 130 can be obtained by applying a voltage.
- a release layer may be formed by implanting ions in advance on the upper surface side of the single crystal piezoelectric layer 130.
- the thickness of the single crystal piezoelectric layer 130 can be easily adjusted by peeling the peeling layer before the upper surface of the single crystal piezoelectric layer 130 is scraped by CMP or the like.
- FIG. 8 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the single crystal piezoelectric layer in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- the upper electrode layer 140 is provided on a part of the upper surface of the single crystal piezoelectric layer 130 by a lift-off method, a plating method, an etching method, or the like.
- the laminated portion 120 is laminated on one main surface 111 side of the base 110.
- the laminated portion 120 may be provided with a through slit communicating with the recess 113 by RIE or the like.
- the first lead-out wiring 160 is formed by using a photolithography method, a lift-off method, or the like so as to be connected to the upper surface of a portion of the upper electrode layer 140 located above the base 110.
- FIG. 9 is a cross-sectional view showing a state in which a hole is provided in the single crystal piezoelectric layer in the method for manufacturing a piezoelectric device according to the first embodiment of the present invention.
- the hole 131 is provided in the single crystal piezoelectric layer 130 by an etching method such as RIE.
- the second lead-out wiring 170 is formed by using a photolithography method, a lift-off method, or the like.
- the lower electrode layer 150 is located only in the recess 113, a voltage is applied by the upper electrode layer 140 and the lower electrode layer 150, and the voltage is simply applied.
- the crystalline piezoelectric layer 130 vibrates, it is possible to suppress the vibration propagating to the peripheral edge of the piezoelectric device 100 through the lower electrode layer 150 and being attenuated. As a result, the excitation efficiency of the piezoelectric device 100 can be increased.
- the base 110 includes a protrusion 114 protruding from the bottom of the recess 113 into the recess 113, and the upper surface 114t of the protrusion 114 is in contact with the lower electrode layer.
- the laminated portion 120 can be supported by the protruding portion 114, and the laminated portion 120 can be prevented from being curved toward the recess 113.
- a hole 131 penetrating from one main surface 111 to the other main surface 112 is provided in a portion of the single crystal piezoelectric layer 130 located above the lower electrode layer 150.
- a second lead-out wiring 170 electrically connected to the lower electrode layer 150 is provided in the hole 131, and the entire inside of the hole 131 is viewed from a direction orthogonal to one of the main surfaces 111. , It overlaps with the upper surface 114t of the protruding portion 114.
- the protruding portion 114 supports the reinforcing lower electrode layer 180, the lower electrode layer 150, and the second drawer wiring 170, and suppresses the occurrence of cracks in the laminated portion 120 when the second drawer wiring 170 is formed. Can be done.
- the portion of the lower electrode layer located between the upper surface 114t of the protruding portion 114 and the hole 131 is thicker than the portion where voltage is applied to the single crystal piezoelectric layer 130. ..
- the electrode extraction portion of the lower electrode layer can be reinforced to improve the reliability of the piezoelectric device 100.
- the inside of the recess 113 is sealed, it is possible to suppress the mixing of foreign matter into the inside of the recess 113.
- the single crystal piezoelectric layer 130 is composed of lithium tantalate, lithium niobate, or quartz, so that the polarization state of the single crystal piezoelectric layer 130 is made uniform.
- the excitation characteristics of the piezoelectric device 100 can be improved.
- the piezoelectric device according to the second embodiment of the present invention is different from the piezoelectric device 100 according to the first embodiment of the present invention in that a pair of electrode layers is mainly composed of only a lower electrode layer. The description of the configuration similar to that of the piezoelectric device 100 according to the first embodiment will not be repeated.
- FIG. 10 is a plan view showing the configuration of the piezoelectric device according to the second embodiment of the present invention.
- FIG. 11 is a cross-sectional view of the piezoelectric device of FIG. 10 as viewed from the direction of the arrow along the XI-XI line.
- the piezoelectric device 200 includes a base portion 110 and a laminated portion 220.
- the laminated portion 220 includes a single crystal piezoelectric layer 130 and a pair of electrode layers.
- the pair of electrode layers applies a voltage to the single crystal piezoelectric layer 130.
- the pair of electrode layers is composed of only the lower electrode layer 250.
- a pair of comb-shaped electrode layers are formed in the lower electrode layer 250.
- a voltage is applied to the single crystal piezoelectric layer 130 located between the comb-shaped electrode layers.
- the single crystal piezoelectric layer 130 is provided with a hole 131 and another hole different from the hole 131.
- the hole 131 is located above one of the pair of electrode layers and the other hole is above the other of the pair of electrode layers.
- the first lead-out wire 160 is connected to the upper surface of the lower electrode layer 250 in the other hole portion in the same manner as the second lead-out wire 170, and covers the inner surface of the other hole portion while being a single crystal. It is drawn out along the surface of the piezoelectric layer 130 opposite to the base 110 side. Below the other holes, other protrusions and other reinforcing lower electrode layers are provided.
- the other reinforcing lower electrode layer, the lower electrode layer 250, and the first drawer wiring 160 are supported by the other protrusions, and cracks are suppressed from occurring in the laminated portion 220 when the first drawer wiring 160 is formed. can do.
- the pair of electrode layers is composed of only the lower electrode layer 250, the pair of electrode layers are arranged in a closed space in the recess 113. As a result, the pair of electrode layers can be protected, so that the environmental resistance of the piezoelectric device 200 can be improved.
- Piezoelectric device 110 base, 111,112 main surface, 113 recess, 114 protrusion, 114t top surface, 120,220 laminated part, 130 single crystal piezoelectric layer, 131 hole part, 140 upper electrode layer, 150,250 Lower electrode layer, 160 1st lead-out wiring, 170 2nd lead-out wiring, 180 Lower electrode layer for reinforcement.
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Abstract
Description
図1は、本発明の実施形態1に係る圧電デバイスの構成を示す平面図である。図2は、図1の圧電デバイスをII-II線矢印方向から見た断面図である。
図3は、本発明の実施形態1に係る圧電デバイスの製造方法において、単結晶圧電体層の下面に下部電極層を設けた状態を示す断面図である。形成時の単結晶圧電体層130の厚みは、本実施形態に係る圧電デバイス100に最終的に含まれる単結晶圧電体層130の厚みより厚い。
以下、本発明の実施形態2に係る圧電デバイスについて図を参照して説明する。本発明の実施形態2に係る圧電デバイスは、1対の電極層が下部電極層のみで構成されている点が主に、本発明の実施形態1に係る圧電デバイス100と異なるため、本発明の実施形態1に係る圧電デバイス100と同様である構成については説明を繰り返さない。
Claims (5)
- 一方の主面と、該一方の主面とは反対側に位置する他方の主面とを含み、かつ、前記一方の主面に形成された凹部を有する基部と、
前記凹部を上方から覆うように前記基部の前記一方の主面側に積層された積層部とを備え、
前記積層部は、少なくとも前記凹部の上方において、単結晶圧電体層と、該単結晶圧電体層に電圧を印加する1対の電極層とを含み、
前記1対の電極層の少なくとも一部を構成し、前記単結晶圧電体層の前記基部側に沿って延在する下部電極層は、前記凹部内のみに位置している、圧電デバイス。 - 前記基部は、前記凹部の底から前記凹部内に突出した突出部を含み、
前記突出部の上面は、前記下部電極層と接している、請求項1に記載の圧電デバイス。 - 前記単結晶圧電体層において前記下部電極層の上方に位置する部分に、前記一方の主面から前記他方の主面まで貫通した孔部が設けられており、
前記孔部内において前記下部電極層に電気的に接続された引出配線が設けられており、
前記一方の主面に直交する方向から見て、前記孔部の内部全体が、前記突出部の前記上面と重なっている、請求項2に記載の圧電デバイス。 - 前記下部電極層において、前記突出部の前記上面と前記孔部との間に位置する部分は、前記単結晶圧電体層に電圧を印加する部分より、厚い、請求項3に記載の圧電デバイス。
- 前記単結晶圧電体層は、タンタル酸リチウム、ニオブ酸リチウムまたは水晶で構成されている、請求項1から請求項4のいずれか1項に記載の圧電デバイス。
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2006001125A1 (ja) * | 2004-06-25 | 2006-01-05 | Murata Manufacturing Co., Ltd. | 圧電デバイス |
JP2009225232A (ja) * | 2008-03-18 | 2009-10-01 | Tdk Corp | 共振子フィルタ |
JP2013005250A (ja) * | 2011-06-17 | 2013-01-07 | Seiko Epson Corp | Memsデバイスの製造方法、memsデバイス、及び超音波トランスデューサー |
JP2015156626A (ja) * | 2014-01-16 | 2015-08-27 | 京セラ株式会社 | 弾性波素子、分波器および通信装置 |
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Publication number | Priority date | Publication date | Assignee | Title |
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WO2006001125A1 (ja) * | 2004-06-25 | 2006-01-05 | Murata Manufacturing Co., Ltd. | 圧電デバイス |
JP2009225232A (ja) * | 2008-03-18 | 2009-10-01 | Tdk Corp | 共振子フィルタ |
JP2013005250A (ja) * | 2011-06-17 | 2013-01-07 | Seiko Epson Corp | Memsデバイスの製造方法、memsデバイス、及び超音波トランスデューサー |
JP2015156626A (ja) * | 2014-01-16 | 2015-08-27 | 京セラ株式会社 | 弾性波素子、分波器および通信装置 |
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