WO2016103515A1 - Method for producing piezoelectric material, piezoelectric element using piezoelectric material produced using same, and device using piezoelectric element - Google Patents

Method for producing piezoelectric material, piezoelectric element using piezoelectric material produced using same, and device using piezoelectric element Download PDF

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Publication number
WO2016103515A1
WO2016103515A1 PCT/JP2014/084702 JP2014084702W WO2016103515A1 WO 2016103515 A1 WO2016103515 A1 WO 2016103515A1 JP 2014084702 W JP2014084702 W JP 2014084702W WO 2016103515 A1 WO2016103515 A1 WO 2016103515A1
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component
piezoelectric
composition
piezoelectric material
temperature
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PCT/JP2014/084702
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French (fr)
Japanese (ja)
Inventor
角　浩二
和也 北田
朋裕 酒井
泰彰 濱田
鉄也 一色
木村　里至
彰雄 伊藤
恒雄 半田
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セイコーエプソン株式会社
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Priority to PCT/JP2014/084702 priority Critical patent/WO2016103515A1/en
Publication of WO2016103515A1 publication Critical patent/WO2016103515A1/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • 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
    • H10N30/09—Forming piezoelectric or electrostrictive materials
    • H10N30/093—Forming inorganic materials
    • 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

Definitions

  • the present invention relates to a method for manufacturing a piezoelectric material, a piezoelectric element using the piezoelectric material manufactured thereby, and a piezoelectric element applied device.
  • the piezoelectric element applied device include an ultrasonic device such as an actuator and an ultrasonic oscillator, an ultrasonic sensor, an ultrasonic motor, a pressure sensor, a pyroelectric element such as a piezoelectric motor and an IR sensor, and a power generation device.
  • Piezoelectric devices mounted on devices using piezoelectric elements as drive sources such as actuators, ultrasonic devices such as ultrasonic oscillators, pyroelectric elements such as ultrasonic motors, pressure sensors, and IR sensors
  • Piezoelectric materials used as piezoelectric layers (piezoelectric ceramics) constituting elements and the like are required to have high piezoelectric characteristics.
  • the characteristics required for the piezoelectric body include various characteristics such as a piezoelectric constant, a dielectric constant, and a Young's modulus.
  • the piezoelectric constant d33
  • the piezoelectric characteristic means a piezoelectric constant (d33).
  • a typical example of a piezoelectric material having high piezoelectric characteristics is lead zirconate titanate (PZT).
  • Such lead-free piezoelectric materials include piezoelectric materials containing alkali metals such as K x Na (1-x) NbO 3 and (Ba, Na) TiO 3, and piezoelectric materials not containing alkali metals such as BiFeO 3 —BaTiO 3. There are materials.
  • phase diagram Morphotropic Phase Boundary
  • PZT is such that the MPB line is positioned substantially parallel to the temperature axis, or approximately the composition axis.
  • the MPB line is generally inclined with respect to the temperature axis in the lead-free piezoelectric material (see, for example, FIG. 1 of Patent Document 1).
  • the MPB line is inclined as described above, even if a composition located on the MPB at a specific temperature, for example, room temperature, is selected according to the required characteristics, if the operating environment temperature changes, the MPB line is separated from the MPB line. There is a problem that there exists a temperature region in which the piezoelectric characteristics deteriorate due to temperature change, heat generation during use, and the like.
  • a lead-free piezoelectric material that has the MPB line as parallel as possible to the temperature axis in the above-described phase diagram and has little temperature dependency is required.
  • the piezoelectric material is required to have high piezoelectric characteristics.
  • a high Curie temperature (Tc) in relation to the use environment temperature is also an important condition required for the piezoelectric material. This is because the piezoelectric material functions only at a temperature lower than the Curie temperature.
  • a piezoelectric material having a high Curie temperature is highly versatile because it can be used in a wider temperature range.
  • a piezoelectric material having a high Curie temperature tends to have poor piezoelectric characteristics.
  • the present invention provides a piezoelectric material having a low environmental load and excellent practicality, a manufacturing method thereof, a piezoelectric element using the piezoelectric material manufactured thereby, and a piezoelectric element application device. Objective.
  • the first component lead-free piezoelectric material comprising a complex oxide having a perovskite structure that is rhombohedral in a single composition and has a Curie temperature of Tc1, and in a single composition
  • a second component lead-free piezoelectric material comprising a complex oxide having a perovskite structure that is a crystal other than rhombohedral and has a Curie temperature of Tc2
  • the first component and the second component are selected so that the absolute value
  • the molar ratio of the second component to (first component + second component) is 0.1 or more in the straight line connecting Tc1 and Tc2. 0.9 or less and 280 ° C
  • the first component and the second component so as to satisfy the relationship of
  • the MPB composition is specified, and the composition has a composition near the MPB.
  • MPB lines are boundaries created by different crystal systems.
  • the piezoelectric constant of the piezoelectric material changes depending on the composition of the material. That is, the piezoelectric characteristics have composition dependency. In the composition on the MPB line (MPB composition), the piezoelectric constant takes a maximum value.
  • a composition region in which the piezoelectric constant is within a range of 70% or more with respect to the piezoelectric constant of the MPB composition at room temperature is a composition near the MPB. It is defined as
  • the first component may be any one of a Ba-based component containing barium at the A site, an Nb-based component containing niobium at the B site, and a Bi-based component containing bismuth at the A site.
  • the two components are any one component different from the first component among the Ba-based component containing barium at the A site, the Nb-based component containing niobium at the B site, and the Bi-based component containing bismuth at the A site. It is preferable. By combining components belonging to different material systems, the advantages of the respective materials are utilized, and the piezoelectric material is more practical.
  • Another aspect of the present invention is a piezoelectric element comprising a piezoelectric layer made of the piezoelectric material manufactured in the above aspect and an electrode provided on the piezoelectric layer.
  • the piezoelectric material does not contain lead, the environmental load can be reduced.
  • the MPB line is set up and a piezoelectric material with less temperature dependency is used, a piezoelectric element with less temperature dependency can be realized.
  • the Curie temperature is high, a piezoelectric element that can be used in a wide temperature range can be realized.
  • another aspect of the present invention is a piezoelectric element application device including the piezoelectric element according to the above aspect. Since the piezoelectric material does not contain lead, environmental load can be reduced. In addition, since a MPB line is set up and a piezoelectric material with less temperature dependency is used, a device with less temperature dependency can be realized. In addition, since the Curie temperature is high, a device that can be used in a wide temperature range can be realized. Examples of such a piezoelectric element applied device include the following.
  • a liquid ejecting head comprising a pressure generating chamber communicating with a nozzle opening and the piezoelectric element described above.
  • a liquid ejecting apparatus comprising the liquid ejecting head according to the above aspect.
  • An ultrasonic sensor comprising: a vibrating portion that transmits the displacement generated by driving the piezoelectric element described above to the outside; and a matching layer that transmits the generated pressure wave to the outside.
  • a piezoelectric motor comprising at least a vibrating body provided with the above-described piezoelectric element and a moving body in contact with the vibrating body.
  • a power generation device comprising an electrode for taking out the electric charge generated by the above-described piezoelectric element from the electrode.
  • the phase diagram explaining the manufacturing method of the piezoelectric material of this invention The figure which shows the relationship between a piezoelectric constant and temperature.
  • 1 is an exploded perspective view illustrating a schematic configuration of a recording head according to an embodiment of the invention.
  • 1 is a plan view of a recording head according to an embodiment of the present invention. 1 is a cross-sectional view of a recording head according to an embodiment of the invention. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment of the present invention.
  • the present invention provides a novel method for obtaining a piezoelectric material having an MPB line standing as much as possible and having a low temperature dependency.
  • this novel technique it is possible to easily obtain a piezoelectric material having a high Curie temperature or high piezoelectric characteristics.
  • T means tetragonal crystal
  • M means monoclinic crystal
  • R means rhombohedral crystal
  • O means orthorhombic crystal
  • C means cubic crystal
  • the piezoelectric material manufacturing method of the present invention realizes a piezoelectric material having an MPB line standing as much as possible by combining two components under the following conditions. Hereinafter, the combination conditions will be described.
  • each of the two components is a lead-free piezoelectric material made of a complex oxide having a perovskite structure.
  • the first component is a rhombohedral complex oxide.
  • the Curie temperature of the first component is Tc1.
  • the second component is a complex oxide having a crystal structure other than rhombohedral.
  • the Curie temperature of the second component is Tc2.
  • rhombohedral crystals are selected as the first component and crystals other than rhombohedral crystals, for example, tetragonal crystals, are selected as the second component because rhombohedral crystals have the largest number of polarization axes.
  • Rhombohedral crystals have four polarization axes (eight polarization axes when considering the plus and minus directions separately), for example, tetragonal, orthorhombic, monoclinic, triclinic Crystals all have one polarization axis (two directions of polarization axes when the positive and negative directions are separated).
  • the deformation of the piezoelectric body is accompanied by rotation of polarization or expansion / contraction / contraction of polarization. Therefore, it can be considered that the piezoelectric characteristics increase as the number of polarization axes increases. That is, it is possible to improve the piezoelectric characteristics by combining the first component of rhombohedral crystal and the second component having other crystal structure.
  • the first component having the Curie temperature Tc1 and the second component having the Curie temperature Tc2 the one having
  • FIG. 1 shows a phase diagram of a piezoelectric material composed of a first component and a second component.
  • the vertical axis X is temperature (° C.).
  • the horizontal axis represents the molar ratio of the second component to the total of the first component and the second component x ((number of moles of the second component) / (number of moles of the first component + number of moles of the second component)).
  • the phase diagram of FIG. 1 shows a composition range (indicated as “R” in the figure) composed of rhombohedral crystals and tetragonal (indicated as T in the figure) or orthorhombic (indicated as “O” in the figure) and cubic.
  • FIG. 1 shows a Curie temperature profile of a composition system with a large value of
  • the Curie temperature profile is indicated by a dotted line.
  • is inclined with respect to the vertical axis.
  • the MPB line m is inclined to the left side in the figure, that is, to the side where the ratio of the first component having a low Tc is large.
  • the Curie temperature profile becomes almost horizontal as shown by the dotted line in FIG. 1, and the MPB line M It becomes possible to obtain a piezoelectric material in which the MPB line M stands.
  • the portion of the dotted profile excluding both ends indicates the Curie temperature Tc3 of a piezoelectric material (two-component piezoelectric material) composed of two components.
  • the Curie temperature Tc3 of the two-component piezoelectric material obtained by selecting the first component and the second component so that
  • the piezoelectric constant of the piezoelectric material varies depending on the composition of the material. That is, the piezoelectric characteristics have composition dependency.
  • the piezoelectric constant takes a maximum value. Therefore, in order to obtain a piezoelectric material with high characteristics, it is preferable to combine the three components under the above conditions and to have a composition near the MPB.
  • a composition region in which the piezoelectric constant is within a range of 70% or more with respect to the piezoelectric constant of the MPB composition at room temperature (any temperature within a range of 20 ° C. or more and 25 ° C. or less) is a composition near the MPB. It is defined as In FIG. 1, the composition in the vicinity of the MPB is shown by hatching.
  • FIG. 2 the piezoelectric characteristics are highest at the Curie temperature regardless of the composition, and become lower as the temperature goes away from the Curie temperature.
  • the temperature change of the piezoelectric characteristics is steep near the Curie temperature, and is gentle in a region away from the Curie temperature to the low temperature side.
  • FIGS. 3A and 3B show this state as contour lines in the phase diagram.
  • FIG. 3A is a phase diagram when the absolute value of the difference between the Curie temperatures Tc1 and Tc2 is large and the MPB line m is inclined.
  • FIG. 3B is a phase diagram when the absolute value of the difference between the Curie temperatures Tc1 and Tc2 is small and the MPB line M is standing.
  • contour lines indicate the height of the piezoelectric constant (d33).
  • the MPB lines m and M in the actual piezoelectric material are not straight lines, and the contour lines are not circular.
  • FIGS. 3A and 3B these are simplified for easy understanding of the explanation. ing.
  • the Curie temperature profile (the solid line profile in FIG. 3A and the dotted line profile in FIG. 3B) is also shown in a more simplified state.
  • Tu represents the upper limit of the operating temperature range of the piezoelectric material.
  • the MPB composition at 25 ° C. is Pm0
  • the composition shifted from the MPB composition Pm0 in the direction in which the ratio of the second component decreases (left side in the figure) is Pm1
  • the ratio of the second component from the MPB composition Pm0 is The composition shifted in the increasing direction (right side in the figure) is shown as Pm2.
  • the MPB composition at 25 ° C. is PM0
  • the composition shifted from the MPB composition PM0 in the direction in which the ratio of the second component decreases (left side in the figure) is PM1
  • the ratio of the second component from the MPB composition PM0 is The composition shifted in the increasing direction (right side in the figure) is shown as PM2.
  • the contour lines are considerably simplified. Actually, however, the change in the piezoelectric constant (d33) near the Curie temperature Tc is steep as shown in FIG. 2 in any composition. Thus, it is gentle in the region away from the Curie temperature to the low temperature side. Therefore, it is preferable that the Curie temperature Tc is sufficiently higher than the upper limit Tu of the use temperature. For example, it is preferably 50 ° C. or more, more preferably 100 ° C. or more higher than the upper limit value Tu of the use temperature. The Curie temperature Tc is preferably higher over the entire composition range. As can be seen from FIG. 1, the two-component piezoelectric material obtained by the present invention has a high Curie temperature Tc3 regardless of the composition. Therefore, from this point, it can be said that there is little change in the temperature dependence tendency of the piezoelectric characteristics due to the composition error.
  • the Curie temperature Tc3 of the two-component piezoelectric material is 280 ° C. or higher in consideration of general use of the piezoelectric material. That is, by setting the Curie temperature Tc3 to 280 ° C. or higher, it is possible to provide a piezoelectric material with very high versatility.
  • the Curie temperature Tc3 is not limited to the composition in the vicinity of the MPB, but in almost the entire composition region, for example, in the portion where the molar ratio x of the second component to the sum of the first component and the second component is 0.1 or more and 0.9 or less. It is preferable that it is 280 degreeC or more. With such a two-component piezoelectric material, the Curie temperature is sufficiently high regardless of the composition, and the change in the temperature dependence tendency of the piezoelectric characteristics due to the composition error can be suppressed to a very small level. Become.
  • the Curie temperature Tc3 it is not essential to satisfy the condition that the Curie temperature Tc3 is 280 ° C. or higher in the entire composition range where the molar ratio x of the second component is 0.1 or higher and 0.9 or lower. In a part of the composition range where the molar ratio x of the second component is 0.1 or more and 0.9 or less, when there is a region where the Curie temperature Tc3 does not reach 280 ° C., the Curie temperature Tc 3 becomes 280 ° C. or more.
  • the composition of the located region is selected.
  • the first component and the second component may be selected under the condition that the Curie temperature Tc3 is 280 ° C. or higher in the composition near the MPB.
  • the first component is rhombohedral in the single composition.
  • Examples of such perovskite complex oxides are shown in Table 1.
  • the second component is a crystal other than rhombohedral crystals in a single composition.
  • Examples of such perovskite complex oxides are shown in Table 2.
  • the first component and the second component are preferably different material systems.
  • the second component is preferably an Nb-based component.
  • the second component is preferably an Nb-based component.
  • FIG. 4 is a graph showing the relationship between the piezoelectric characteristics (d33) of the piezoelectric material and the Curie temperature. As shown in FIG. 4, the relationship between the piezoelectric properties (d33) of the piezoelectric material and the Curie temperature is as follows: Ba system containing barium at the A site, Nb system containing niobium at the B site, and Bi containing bismuth at the A site. There are three types of systems.
  • the Curie temperature Tc becomes an intermediate value between the two as shown by the dotted line in FIG. 4, and the piezoelectric characteristic (d33) is Since the maximum value is taken in the vicinity of the MPB line, it is expected that the value exceeds the larger value of both as shown by the solid line in FIG. The same can be said when two kinds of materials of the same system are combined.
  • materials belonging to different systems often have different characteristics. Therefore, when materials belonging to different systems are combined, the advantages of the respective materials are utilized, and a piezoelectric material with more practicality can be obtained.
  • the absolute value of the difference between the Curie temperature Tc1 of the first component and the Curie temperature Tc2 of the second component is within 50 ° C. and the MPB line is as standing as possible, the Curie temperature near the MPB composition is The value of Tc3 shown below should not be significantly different.
  • FIG. 5 shows as a first component (Bi, Na, La) TiO 3, a phase diagram of a combination by selecting NaNbO 3 as the second component.
  • the first component (Bi, Na, La) TiO 3 is a rhombohedral crystal alone, and its Curie temperature Tc1 is 335 ° C.
  • NaNbO 3 as the second component alone is tetragonal and has a Curie temperature Tc2 of 365 ° C. Therefore, the condition of
  • the MPB line M1 stands almost vertically and only changes in a range where the composition ratio of the second component ranges from 0.5 to 0.6.
  • the Curie temperature Tc3 is 350 ° C. In this example, the Curie temperature Tc3 is 280 ° C. or higher over the entire composition range where the molar ratio x of the second component to the total of the first component and the second component is 0.1 to 0.9.
  • the molar ratio x with the two components can be selected within the range of 0.1 or more and 0.9 or less.
  • a piezoelectric material having high piezoelectric characteristics can be obtained.
  • both molar ratio of 0.40: to 0.60 A method for forming a piezoelectric layer with a piezoelectric material having a composition will be described.
  • Such a precursor solution is dropped on a substrate, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating.
  • the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes.
  • the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes.
  • baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus.
  • FIG. 6 shows a phase diagram in which (Bi, Na, La) TiO 3 is selected as the first component and (K, Na) NbO 3 to which Li and Ta are added as the second component is selected and combined.
  • the first component (Bi, Na, La) TiO 3 is a rhombohedral crystal alone, and its Curie temperature Tc1 is 335 ° C.
  • K, Na) NbO 3 to which Li and Ta as the second component are added is orthorhombic alone, and its Curie temperature Tc is 325 ° C. Therefore, the condition of
  • the MPB line M2 stands almost vertically and only changes in the range of the composition ratio of the second component from 0.46 to 0.63.
  • the Curie temperature Tc3 is 330 ° C. In this example, the Curie temperature Tc3 is 280 ° C. or higher over the entire composition range where the molar ratio x of the second component to the total of the first component and the second component is 0.1 to 0.9.
  • the molar ratio x with the two components can be selected within the range of 0.1 or more and 0.9 or less.
  • a piezoelectric material having high piezoelectric characteristics can be obtained.
  • Starting materials include bismuth 2-ethylhexanoate, sodium 2-ethylhexanoate, lanthanum 2-ethylhexanoate, titanium 2-ethylhexanoate, potassium 2-ethylhexanoate, 2-ethylhexanoic acid Niobium, lithium 2-ethylhexanoate, and tantalum 2-ethylhexanoate are mixed in an n-octane solution with the molar ratio of the metal elements adjusted so as to match the stoichiometric ratio of the above composition. Make a body solution.
  • Such a precursor solution is dropped on a substrate, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating.
  • the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes.
  • the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes.
  • baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus.
  • Figure 7 shows as a first component (Bi, Na, La) TiO 3, as the second component (Bi, K) phase diagram which is a combination by selecting TiO 3.
  • the first component (Bi, Na, La) TiO 3 is a rhombohedral crystal alone, and its Curie temperature Tc1 is 335 ° C.
  • the second component (Bi, K) TiO 3 alone is a tetragonal crystal, and its Curie temperature Tc is 380 ° C. Therefore, the condition of
  • the MPB line M3 stands substantially vertically and only changes in the range of the composition ratio of the second component from 0.31 to 0.35.
  • the Curie temperature Tc3 is 357.5 ° C. In this example, the Curie temperature Tc3 is 280 ° C. or higher over the entire composition range where the molar ratio x of the second component to the total of the first component and the second component is 0.1 to 0.9.
  • the molar ratio x with the two components can be selected within the range of 0.1 or more and 0.9 or less.
  • a piezoelectric material having high piezoelectric characteristics can be obtained.
  • both molar A method for forming a piezoelectric layer with a piezoelectric material having a composition of 0.65: 0.35 will be described.
  • Such a precursor solution is dropped on a substrate, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating.
  • the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes.
  • the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes.
  • baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus.
  • FIG. 8 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid jet head including a piezoelectric element according to an embodiment of the present invention
  • FIG. 9 is a plan view of FIG. 10 is a cross-sectional view taken along line AA ′ of FIG.
  • the flow path forming substrate 10 of this embodiment is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.
  • the flow path forming substrate 10 has a plurality of pressure generating chambers 12 arranged in parallel in the width direction.
  • a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a supply path 14 and a communication path 15.
  • the communication part 13 communicates with a manifold part 31 of a protective substrate, which will be described later, and constitutes a part of a manifold that becomes a common ink chamber for each pressure generating chamber 12.
  • the ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13.
  • the ink supply path 14 is formed by narrowing the width of the flow path from one side.
  • the ink supply path may be formed by narrowing the width of the flow path from both sides.
  • the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path.
  • the flow path forming substrate 10 is provided with a liquid flow path including the pressure generation chamber 12, the communication portion 13, the ink supply path 14, and the communication path 15.
  • a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like.
  • the nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.
  • the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the elastic film 50 is made of titanium oxide or the like.
  • An adhesion layer 56 is provided for improving the adhesion between the first electrode 60 and the base.
  • An insulator film made of zirconium oxide or the like may be formed between the elastic film 50 and the adhesion layer 56 as necessary.
  • a first electrode 60 a piezoelectric layer 70 which is a thin film having a thickness of 2 ⁇ m or less, preferably 0.3 to 1.5 ⁇ m, and a second electrode 80 are laminated.
  • the piezoelectric element 300 is configured.
  • the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80.
  • one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12.
  • the first electrode 60 is a common electrode of the piezoelectric element 300
  • the second electrode 80 is an individual electrode of the piezoelectric element 300.
  • the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device.
  • the elastic film 50, the adhesion layer 56, the first electrode 60, and the insulator film provided as necessary function as a vibration plate.
  • the present invention is not limited to this.
  • the elastic film 50 and the adhesion layer 56 may not be provided.
  • the piezoelectric element 300 itself may substantially serve as a diaphragm.
  • the piezoelectric layer 70 is made of the above-described piezoelectric material of the present invention.
  • a piezoelectric material has high piezoelectric characteristics and dielectric characteristics in a wide use environment temperature range, and also has a high Curie temperature, so that a piezoelectric element exhibiting excellent displacement characteristics in a wide use environment temperature can be realized.
  • the piezoelectric material does not contain lead, the load on the environment can be reduced.
  • Each second electrode 80 that is an individual electrode of the piezoelectric element 300 is drawn from the vicinity of the end on the ink supply path 14 side and extended to the adhesion layer 56, for example, gold (Au) or the like.
  • the lead electrode 90 which consists of is connected.
  • a protection having a manifold portion 31 constituting at least a part of the manifold 100 On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the first electrode 60, the adhesion layer 56, and the lead electrode 90, a protection having a manifold portion 31 constituting at least a part of the manifold 100.
  • the substrate 30 is bonded via an adhesive 35.
  • the manifold portion 31 penetrates the protective substrate 30 in the thickness direction and is formed across the width direction of the pressure generating chamber 12.
  • the manifold 100 is configured as a common ink chamber for the pressure generation chambers 12.
  • the communication portion 13 of the flow path forming substrate 10 may be divided into a plurality of pressure generation chambers 12 and only the manifold portion 31 may be used as a manifold. Further, for example, only the pressure generation chamber 12 is provided in the flow path forming substrate 10, and the manifold 100 is attached to a member (for example, the elastic film 50, the adhesion layer 56, etc.) interposed between the flow path forming substrate 10 and the protective substrate 30. An ink supply path 14 that communicates with each pressure generating chamber 12 may be provided.
  • a piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 facing the piezoelectric element 300.
  • the piezoelectric element holding part 32 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.
  • a protective substrate 30 it is preferable to use substantially the same material as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc.
  • the same material as the flow path forming substrate 10 is used.
  • the silicon single crystal substrate was used.
  • the protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction.
  • the vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.
  • a drive circuit 120 for driving the piezoelectric elements 300 arranged in parallel is fixed.
  • a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 120.
  • the drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 made of a conductive wire such as a bonding wire.
  • a compliance substrate 40 composed of a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30.
  • the sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the manifold portion 31 is sealed by the sealing film 41.
  • the fixing plate 42 is formed of a relatively hard material. Since the area of the fixing plate 42 facing the manifold 100 is an opening 43 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 41. Has been.
  • ink is taken in from an ink introduction port connected to an external ink supply means (not shown), and the interior from the manifold 100 to the nozzle opening 21 is filled with ink, and then driven.
  • a voltage is applied between each of the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, and the elastic film 50, the adhesion layer 56, the first electrode 60, and the piezoelectric body.
  • a silicon dioxide film made of silicon dioxide (SiO 2 ) or the like that constitutes the elastic film 50 is formed on the surface of the flow path forming substrate wafer 110 that is a silicon wafer by thermal oxidation or the like.
  • an adhesion layer 56 made of titanium oxide or the like is formed on the elastic film 50 (silicon dioxide film) by a reactive sputtering method, thermal oxidation, or the like.
  • the first electrode 60 is formed on the adhesion layer 56.
  • the first electrode 60 made of platinum, iridium, iridium oxide, or a laminated structure thereof is formed on the adhesion layer 56.
  • the adhesion layer 56 and the first electrode 60 can be formed by, for example, a sputtering method or a vapor deposition method.
  • the method for manufacturing the piezoelectric layer 70 is not particularly limited.
  • a solution obtained by dissolving and dispersing an organometallic compound in a solvent is applied and dried, and further fired at a high temperature to obtain the piezoelectric layer 70 made of a metal oxide.
  • the piezoelectric layer 70 can be formed using a chemical solution method such as a MOD (Metal-Organic Decomposition) method or a sol-gel method.
  • the piezoelectric layer 70 may be a laser ablation method, a sputtering method, a pulse laser deposition method (PLD method), a CVD method, an aerosol deposition method, or the like.
  • the piezoelectric layer 70 is formed by a chemical coating method
  • 2-ethylhexanoate or acetate containing a desired element is used as a starting material.
  • a piezoelectric layer made of a perovskite complex oxide containing bismuth, barium, iron and titanium bismuth 2-ethylhexanoate, barium 2-ethylhexanoate, iron 2-ethylhexanoate, 2-
  • titanium ethylhexanoate is used.
  • a precursor solution is prepared by mixing such a raw material with a solvent such as an n-octane solution and adjusting the molar ratio of the metal elements so as to coincide with the stoichiometric ratio.
  • the precursor solution is dropped onto the previously prepared lower electrode, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating.
  • the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes.
  • the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes.
  • baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus.
  • the piezoelectric layer 70 can be formed by repeating the above steps five times.
  • the second electrode 80 made of platinum or the like is formed on the piezoelectric layer 70 by a sputtering method or the like, and the piezoelectric layer 70 and the piezoelectric layer 70 and the regions facing the pressure generation chambers 12 are formed.
  • the second electrode 80 is simultaneously patterned to form the piezoelectric element 300 including the first electrode 60, the piezoelectric layer 70, and the second electrode 80.
  • the patterning of the piezoelectric layer 70 and the second electrode 80 can be performed collectively by dry etching via a resist (not shown) formed in a predetermined shape. Thereafter, post-annealing may be performed in a temperature range of 600 ° C. to 800 ° C. as necessary. Thereby, a good interface between the piezoelectric layer 70 and the first electrode 60 or the second electrode 80 can be formed, and the crystallinity of the piezoelectric layer 70 can be improved.
  • a lead electrode 90 made of, for example, gold (Au) over the entire surface of the flow path forming substrate wafer patterning is performed for each piezoelectric element 300 through a mask pattern made of, for example, a resist. .
  • a protective substrate wafer which is a silicon wafer and serves as a plurality of protective substrates 30, is bonded to the piezoelectric element 300 side of the flow path forming substrate wafer via the adhesive 35, the flow path forming substrate wafer is preliminarily fixed. Reduce the thickness to.
  • a mask film is newly formed on the flow path forming substrate wafer and patterned into a predetermined shape.
  • the flow path forming substrate wafer is subjected to anisotropic etching (wet etching) using an alkaline solution such as KOH through the mask film, so that the pressure generating chamber 12, the communicating portion 13, the ink corresponding to the piezoelectric element 300 is obtained.
  • anisotropic etching wet etching
  • an alkaline solution such as KOH
  • the configuration and manufacturing method are not limited to those described above.
  • a silicon single crystal substrate is exemplified as the substrate 10, but the present invention is not particularly limited thereto, and for example, a substrate such as an SOI substrate or glass may be used.
  • the piezoelectric element 300 in which the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are sequentially laminated on the substrate 10 is illustrated, but the invention is not particularly limited thereto.
  • the present invention can also be applied to a longitudinal vibration type piezoelectric element in which electrode forming materials are alternately stacked and expanded and contracted in the axial direction.
  • the piezoelectric layer may be a bulk instead of the thin film as described above.
  • carbonates or oxides are used as starting materials. For example, K 2 CO 3 , Na 2 CO 3 , and Nb 2 O 5 . These starting materials are weighed to match the stoichiometric ratio and wet mixed in ethanol using a ball mill. The obtained mixture is dried and calcined at 700 ° C. for 3 hours. An appropriate amount of PVA as a binder is added to these calcined powders, pulverized and mixed using a mortar, particle size adjustment is performed through a 150-mesh sieve, and the obtained powder is formed into disk-shaped pellets with a single screw press.
  • the molded pellets and the remainder of the calcined powder are placed in a crucible and fired at 1100 ° C. for 3 hours to obtain a disk-shaped oxide.
  • both surfaces of the obtained disk-shaped oxide are polished to prepare a surface, and a silver paste is applied and baked on this to obtain a piezoelectric body having a silver electrode.
  • starting materials include barium carbonate, titanium oxide, bismuth oxide, tin oxide, iron oxide, zirconium oxide, lanthanum oxide, and lithium carbonate.
  • the ink jet recording head of these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus.
  • FIG. 11 is a schematic view showing an example of the ink jet recording apparatus.
  • cartridges 2A and 2B constituting ink supply means are detachably provided, and a carriage on which the recording head units 1A and 1B are mounted. 3 is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction.
  • the recording head units 1A and 1B for example, are configured to eject a black ink composition and a color ink composition, respectively.
  • the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5.
  • the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.
  • each of the ink jet recording head units 1A and 1B has one ink jet recording head I.
  • the present invention is not particularly limited to this.
  • one ink jet recording head unit 1A or 1 1B may have two or more ink jet recording heads.
  • the ink jet recording head used in the ink jet recording apparatus has been described as an example of the liquid ejecting head.
  • the piezoelectric material obtained by the manufacturing method of the present invention is a liquid other than ink.
  • the present invention can also be applied to a liquid ejecting head that ejects water.
  • liquid ejecting heads include various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in manufacturing color filters such as liquid crystal displays, organic EL displays, and FED (field emission displays). ) And the like, electrode material ejection heads used for electrode formation, bio-organic matter ejection heads used for biochip production, and the like.
  • the piezoelectric element of the present invention can be applied to a piezoelectric element of a liquid ejecting head typified by an ink jet recording head, but is not limited thereto.
  • the piezoelectric material of the present invention can also be applied to a piezoelectric element used for a piezoelectric element application device other than a liquid jet head. Examples of such piezoelectric element applied devices include ultrasonic sensors, piezoelectric motors, ultrasonic motors, piezoelectric transformers, vibratory dust removal devices, pressure-electric converters, ultrasonic transmitters, pressure sensors, and acceleration sensors. .
  • power generation devices can be mentioned.
  • a power generation device a power generation device using pressure-electric conversion effect, a power generation device using electron excitation (photoelectromotive force) by light, a power generation device using electron excitation (thermoelectromotive force) by heat, a vibration is used.
  • the piezoelectric material of the present invention can be suitably used for a ferroelectric element such as a ferroelectric memory.
  • I Inkjet recording head (liquid jet head), 10 flow path forming substrate, 12 pressure generating chamber, 13 communication section, 14 ink supply path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 manifold section, 32 piezoelectric element Holding part, 40 compliance substrate, 50 elastic film, 60 first electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 manifold, 120 drive circuit, 300 piezoelectric element

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Abstract

A method for producing a two-component piezoelectric material comprising: a first lead-free piezoelectric material component comprising a complex oxide having a perovskite structure, having a Curie temperature of Tc1, and forming rhombohedral crystals in an independent composition; and a second lead-free piezoelectric material component comprising a complex oxide having a perovskite structure, having a Curie temperature of Tc2, and forming a crystal other than a rhombohedral crystal in an independent composition. Therein, the first component and the second component are selected in a manner such that the absolute value of the difference between Tc1 and Tc2, |Tc1-Tc2|, is 50°C or less, and the first component and the second component are combined with one another by using a phase diagram in which the horizontal axis represents the compositional ratio of the first and second components and the vertical axis represents temperature and selecting a composition that is located in the region at or above 280°C, exhibits a mole ratio of the second component to the total of the first and second components of 0.1 to 0.9, inclusive, and is located along a straight line connecting Tc1 and Tc2.

Description

圧電材料の製造方法、並びにこれにより製造された圧電材料を用いた圧電素子、及び圧電素子応用デバイスPiezoelectric material manufacturing method, piezoelectric element using the piezoelectric material manufactured thereby, and piezoelectric element application device
　本発明は、圧電材料の製造方法、並びにこれにより製造された圧電材料を用いた圧電素子、及び圧電素子応用デバイスに関する。圧電素子応用デバイスとしては、アクチュエーター、超音波発振機等の超音波デバイス、超音波センサー、超音波モーター、圧力センサー、圧電モーター、ＩＲセンサー等の焦電素子、発電装置等が挙げられる。 The present invention relates to a method for manufacturing a piezoelectric material, a piezoelectric element using the piezoelectric material manufactured thereby, and a piezoelectric element applied device. Examples of the piezoelectric element applied device include an ultrasonic device such as an actuator and an ultrasonic oscillator, an ultrasonic sensor, an ultrasonic motor, a pressure sensor, a pyroelectric element such as a piezoelectric motor and an IR sensor, and a power generation device.
　従来、アクチュエーター、超音波発振機等の超音波デバイス、超音波モーター、圧力センサー、ＩＲセンサー等の焦電素子等、圧電素子を駆動源として用いたデバイス（圧電素子応用デバイス）に搭載される圧電素子などを構成する圧電体層（圧電セラミックス）として用いられる圧電材料には高い圧電特性が求められている。圧電体に要求される特性としては、圧電定数、誘電率、ヤング率など、さまざまな特性があるが、本発明では、圧電定数（ｄ３３）に着目する。以下、「圧電特性」とは、圧電定数（ｄ３３）を意味するものとする。高い圧電特性を持つ圧電材料の代表例として、チタン酸ジルコン酸鉛（ＰＺＴ）が挙げられる。 Piezoelectric devices mounted on devices using piezoelectric elements as drive sources (piezoelectric device application devices) such as actuators, ultrasonic devices such as ultrasonic oscillators, pyroelectric elements such as ultrasonic motors, pressure sensors, and IR sensors Piezoelectric materials used as piezoelectric layers (piezoelectric ceramics) constituting elements and the like are required to have high piezoelectric characteristics. The characteristics required for the piezoelectric body include various characteristics such as a piezoelectric constant, a dielectric constant, and a Young's modulus. In the present invention, attention is paid to the piezoelectric constant (d33). Hereinafter, the “piezoelectric characteristic” means a piezoelectric constant (d33). A typical example of a piezoelectric material having high piezoelectric characteristics is lead zirconate titanate (PZT).
　しかしながら、環境問題の観点から、鉛の含有量を抑えた圧電材料が求められている。このような非鉛系圧電材料としては、ＫｘＮａ（１－ｘ）ＮｂＯ３、（Ｂａ，Ｎａ）ＴｉＯ３などアルカリ金属を含む圧電材料や、ＢｉＦｅＯ３－ＢａＴｉＯ３などアルカリ金属を含まない圧電材料がある。 However, from the viewpoint of environmental problems, there is a demand for a piezoelectric material with a reduced lead content. Such lead-free piezoelectric materials include piezoelectric materials containing alkali metals such as K x Na (1-x) NbO 3 and (Ba, Na) TiO 3, and piezoelectric materials not containing alkali metals such as BiFeO 3 —BaTiO 3. There are materials.
　このような圧電材料において、組成相境界（ＭＰＢ：Ｍｏｒｐｈｏｔｏｒｏｐｉｃ　Ｐｈａｓｅ　Ｂｏｕｎｄａｒｙ）付近の組成を使用することにより、大きな圧電特性が得られることが知られている。しかしながら、横軸に組成を縦軸に温度を採った相図（以下、「相図」という）において、ＰＺＴはＭＰＢラインが温度軸に対してほぼ平行に位置する、または組成軸に対してほぼ垂直に位置するのに対し、非鉛系圧電材料では、一般的に、そのＭＰＢラインが温度軸に対して傾斜している（例えば、特許文献１の図１など参照）。このようにＭＰＢラインが傾斜している場合、要求特性に応じて特定の温度、例えば室温でＭＰＢ上に位置する組成を選んでも、使用環境温度が変化すればＭＰＢラインから離れることから、使用環境温度の変化や使用中の発熱等に起因して圧電特性が低下する温度領域が存在するという問題がある。 It is known that in such a piezoelectric material, a large piezoelectric characteristic can be obtained by using a composition in the vicinity of a composition phase boundary (MPB: Morphotropic Phase Boundary). However, in a phase diagram (hereinafter referred to as “phase diagram”) in which the composition is plotted on the horizontal axis and the temperature is plotted on the vertical axis, PZT is such that the MPB line is positioned substantially parallel to the temperature axis, or approximately the composition axis. In contrast, the MPB line is generally inclined with respect to the temperature axis in the lead-free piezoelectric material (see, for example, FIG. 1 of Patent Document 1). When the MPB line is inclined as described above, even if a composition located on the MPB at a specific temperature, for example, room temperature, is selected according to the required characteristics, if the operating environment temperature changes, the MPB line is separated from the MPB line. There is a problem that there exists a temperature region in which the piezoelectric characteristics deteriorate due to temperature change, heat generation during use, and the like.
　よって、上述した相図においてＭＰＢラインが温度軸に対してなるべく平行で、温度依存性の少ない非鉛系圧電材料が求められている。また、圧電材料に、高い圧電特性が求められていることは言うまでもないが、使用環境温度との関係で、キュリー温度（Ｔｃ）が高いことも、圧電材料に求められる重要な条件である。圧電材料は、キュリー温度より低い温度でしか機能しないからである。キュリー温度が高い圧電材料は、より広い温度範囲で使用することが可能であるため、汎用性が高い。しかしながら、一般的にキュリー温度が高い圧電材料は圧電特性が悪いという傾向がある。 Therefore, a lead-free piezoelectric material that has the MPB line as parallel as possible to the temperature axis in the above-described phase diagram and has little temperature dependency is required. Needless to say, the piezoelectric material is required to have high piezoelectric characteristics. However, a high Curie temperature (Tc) in relation to the use environment temperature is also an important condition required for the piezoelectric material. This is because the piezoelectric material functions only at a temperature lower than the Curie temperature. A piezoelectric material having a high Curie temperature is highly versatile because it can be used in a wider temperature range. However, generally, a piezoelectric material having a high Curie temperature tends to have poor piezoelectric characteristics.
　ここで、ＭＰＢラインを温度軸に対してなるべく平行にする、温度依存性を低減する等の条件を満足した圧電材料を得るために、異なる組成の圧電材料を複数組み合わせて利用するという考え方がある（特許文献２、３など参照）。なお、以下の説明において、横軸に組成を縦軸に温度を採った相図において、ＭＰＢラインが温度軸に対して平行に近い状態、または組成軸に対して垂直に近い状態を、「ＭＰＢラインが立っている」と表現する。 Here, in order to obtain a piezoelectric material satisfying conditions such as making the MPB line parallel to the temperature axis as much as possible and reducing temperature dependency, there is a concept of using a combination of a plurality of piezoelectric materials having different compositions. (See Patent Documents 2 and 3). In the following description, in the phase diagram in which the horizontal axis represents the composition and the vertical axis represents the temperature, the MPB line is almost parallel to the temperature axis or perpendicular to the composition axis. "The line is standing."
特開２００９－２１５１１１号公報JP 2009-215111 A 特開２００３－２７７１４３号公報JP 2003-277143 A 特開２０１１－１８１７６４号公報JP 2011-181764 A
　しかし、どのような成分をどのような組成で組みあわせればＭＰＢラインが立って温度依存性の少ない圧電材料が得られるのか、どのような成分をどのような組成で組みあわせれば圧電特性の高い圧電材料が得られるのか、どのような成分をどのような組成で組みあわせればキュリー温度が高い圧電材料が得られるのか、に関して明確な指標を示す知見は未だ存在しない。また、温度依存性が少ない、圧電特性が高い、キュリー温度が高い、といった複数の条件のうち、１つを満たすだけでは、必ずしも実用性の高い圧電材料とはいえない。実用性の高い圧電材料を得るには、複数の条件を同時に満たすような組成が好ましい。明確な指標が無い中で、そのような成分の組み合わせと組成を見出すのは極めて困難である。現在、このような複数の条件を同時に満たす圧電材料は、実質的にＰＺＴしか存在しない。そして、現在、ＰＺＴに匹敵する非鉛系圧電材料は存在しない。そこで、ＰＺＴのように、ＭＰＢラインが立っており、広い使用環境温度範囲で圧電特性が高く、また、キュリー温度が高い非鉛系圧電材料の出現が熱望されている。 However, what kind of components are combined with what composition can produce a piezoelectric material with an MPB line standing and less temperature dependence, and what kind of components are combined with what composition is a piezoelectric material with high piezoelectric characteristics. There is still no knowledge showing a clear index as to whether a material can be obtained and what kind of components are combined in what composition to obtain a piezoelectric material having a high Curie temperature. In addition, it is not necessarily a highly practical piezoelectric material if only one of a plurality of conditions such as low temperature dependency, high piezoelectric characteristics, and high Curie temperature is satisfied. In order to obtain a highly practical piezoelectric material, a composition that satisfies a plurality of conditions simultaneously is preferable. In the absence of a clear indicator, it is extremely difficult to find such component combinations and compositions. Currently, there is substantially only PZT as a piezoelectric material that satisfies such a plurality of conditions simultaneously. At present, there is no lead-free piezoelectric material comparable to PZT. Therefore, like PZT, the MPB line stands, and the appearance of a lead-free piezoelectric material having a high piezoelectric characteristic in a wide use environment temperature range and a high Curie temperature is eagerly desired.
　なお、このような問題は、インクジェット式記録ヘッドだけではなく、勿論、インク以外の液滴を吐出する他の液体噴射ヘッドにおいても同様に存在し、また、液体噴射ヘッド以外に用いられる圧電素子においても同様に存在する。 Such a problem exists not only in the ink jet recording head, but of course in other liquid ejecting heads that eject droplets other than ink, and also in piezoelectric elements used in other than liquid ejecting heads. Exist as well.
　本発明はこのような事情に鑑み、環境負荷が低く、実用性に優れた圧電材料及びその製造方法、並びにこれにより製造された圧電材料を用いた圧電素子及び圧電素子応用デバイスを提供することを目的とする。 In view of such circumstances, the present invention provides a piezoelectric material having a low environmental load and excellent practicality, a manufacturing method thereof, a piezoelectric element using the piezoelectric material manufactured thereby, and a piezoelectric element application device. Objective.
　上記課題を解決する本発明の態様は、単独組成では菱面体晶であり且つキュリー温度がＴｃ１であるペロブスカイト型構造を有する複合酸化物からなる第１成分の非鉛系圧電材料と、単独組成では菱面体晶以外の結晶であり且つキュリー温度がＴｃ２であるペロブスカイト型構造を有する複合酸化物からなる第２成分の非鉛系圧電材料と、からなる２成分系圧電材料の製造方法であって、前記Ｔｃ１と前記Ｔｃ２との差の絶対値｜Ｔｃ１－Ｔｃ２｜が５０℃以下となるように、前記第１成分と第２成分とを選定し、横軸に前記第１成分と前記第２成分との組成比を、縦軸に温度を採った相図において、前記Ｔｃ１と前記Ｔｃ２とを結ぶ直線のうち、第２成分の（第１成分＋第２成分）に対するモル比率が０．１以上０．９以下且つ２８０℃以上に位置する領域の組成を選択して、前記第１成分と前記第２成分とを組み合わせることを特徴とする２成分系圧電材料の製造方法にある。 An aspect of the present invention that solves the above problems is the first component lead-free piezoelectric material comprising a complex oxide having a perovskite structure that is rhombohedral in a single composition and has a Curie temperature of Tc1, and in a single composition A second component lead-free piezoelectric material comprising a complex oxide having a perovskite structure that is a crystal other than rhombohedral and has a Curie temperature of Tc2, The first component and the second component are selected so that the absolute value | Tc1−Tc2 | of the difference between the Tc1 and the Tc2 is 50 ° C. or less, and the horizontal axis represents the first component and the second component. In the phase diagram in which the temperature is plotted on the vertical axis, the molar ratio of the second component to (first component + second component) is 0.1 or more in the straight line connecting Tc1 and Tc2. 0.9 or less and 280 ° C By selecting the composition of a region located above, is in the method for producing a two-component piezoelectric material characterized by combining said first component and said second component.
　かかる態様では、鉛を含有していないため環境負荷が低く、また、ＭＰＢラインが立っており、温度依存性が少なく、また、キュリー温度が高い圧電材料を製造できる。 In such an embodiment, since it does not contain lead, the environmental load is low, the MPB line is standing, the temperature dependence is low, and a piezoelectric material having a high Curie temperature can be manufactured.
　ここで、｜Ｔｃ１－Ｔｃ２｜／｜Ｔｃ１＋Ｔｃ２｜≦０．１の関係を満たすように、前記第１成分と前記第２成分とを選定することが好ましい。これによれば、Ｔｃ１とＴｃ２との差の絶対値｜Ｔｃ１－Ｔｃ２｜の範囲をさらに限定することにより、より、ＭＰＢラインが立っており、温度依存性が少ない圧電材料を実現できる。 Here, it is preferable to select the first component and the second component so as to satisfy the relationship of | Tc1-Tc2 | / | Tc1 + Tc2 | ≦ 0.1. According to this, by further limiting the range of the absolute value | Tc1−Tc2 | of the difference between Tc1 and Tc2, it is possible to realize a piezoelectric material having more MPB lines and less temperature dependency.
　また、横軸に前記第１成分と前記第２成分との合計に対する前記第２成分のモル比を、縦軸に温度を採った相図において、ＭＰＢ組成を特定し、ＭＰＢ近傍の組成を有するように前記第１成分と前記第２成分とを組み合わせることが好ましい。ＭＰＢラインは、異なる結晶系によって作られる境界線である。圧電材料の圧電定数は、当該材料の組成によって変化する。すなわち、圧電特性は組成依存性を有する。ＭＰＢライン上の組成（ＭＰＢ組成）において、圧電定数は極大値をとる。ＭＰＢラインが立っている圧電材料の、ＭＰＢ近傍の組成を採用することにより、圧電特性が高い状態を、広い温度範囲で維持することが可能である。本発明においては、圧電定数が、室温（２０℃以上２５℃以下の範囲内における任意の温度）におけるＭＰＢ組成の圧電定数に対して７０％以上の範囲内である組成領域を、ＭＰＢ近傍の組成と定義する。 Further, in the phase diagram in which the horizontal axis represents the molar ratio of the second component to the sum of the first component and the second component, and the vertical axis represents temperature, the MPB composition is specified, and the composition has a composition near the MPB. Thus, it is preferable to combine the first component and the second component. MPB lines are boundaries created by different crystal systems. The piezoelectric constant of the piezoelectric material changes depending on the composition of the material. That is, the piezoelectric characteristics have composition dependency. In the composition on the MPB line (MPB composition), the piezoelectric constant takes a maximum value. By adopting a composition in the vicinity of the MPB of the piezoelectric material on which the MPB line stands, it is possible to maintain a high piezoelectric characteristic in a wide temperature range. In the present invention, a composition region in which the piezoelectric constant is within a range of 70% or more with respect to the piezoelectric constant of the MPB composition at room temperature (any temperature within a range of 20 ° C. or more and 25 ° C. or less) is a composition near the MPB. It is defined as
　また、前記第１成分は、Ａサイトにバリウムを含むＢａ系、Ｂサイトにニオブを含むＮｂ系、及びＡサイトにビスマスを含むＢｉ系の成分のうち、いずれか１つの成分であり、前記第２成分は、Ａサイトにバリウムを含むＢａ系、Ｂサイトにニオブを含むＮｂ系、及びＡサイトにビスマスを含むＢｉ系の成分のうち、前記第１成分とは異なるいずれか１つの成分であることが好ましい。互いに異なる材料系に属する成分を組み合わせることによって、それぞれの材料が持つ長所が活かされ、より実用性に優れた圧電材料となる。 The first component may be any one of a Ba-based component containing barium at the A site, an Nb-based component containing niobium at the B site, and a Bi-based component containing bismuth at the A site. The two components are any one component different from the first component among the Ba-based component containing barium at the A site, the Nb-based component containing niobium at the B site, and the Bi-based component containing bismuth at the A site. It is preferable. By combining components belonging to different material systems, the advantages of the respective materials are utilized, and the piezoelectric material is more practical.
　本発明の他の態様は、上記態様で製造された圧電材料からなる圧電体層と、前記圧電体層に設けられた電極と、を備えたことを特徴とする圧電素子にある。 Another aspect of the present invention is a piezoelectric element comprising a piezoelectric layer made of the piezoelectric material manufactured in the above aspect and an electrode provided on the piezoelectric layer.
　これによれば、圧電材料が鉛を含有していないため環境負荷を低減することができる。また、ＭＰＢラインが立っており、温度依存性が少ない圧電材料を利用するため、温度依存性が少ない圧電素子が実現できる。また、キュリー温度が高いため、広い温度範囲で使用可能な圧電素子が実現できる。 According to this, since the piezoelectric material does not contain lead, the environmental load can be reduced. In addition, since the MPB line is set up and a piezoelectric material with less temperature dependency is used, a piezoelectric element with less temperature dependency can be realized. In addition, since the Curie temperature is high, a piezoelectric element that can be used in a wide temperature range can be realized.
　また、本発明の他の態様は、上記態様の圧電素子を備えた圧電素子応用デバイスである。圧電材料が鉛を含有していないため環境負荷を低減することができる。また、ＭＰＢラインが立っており、温度依存性の少ない圧電材料を利用するため、温度依存性が少ないデバイスが実現できる。また、キュリー温度が高いため、広い温度範囲で使用可能なデバイスが実現できる。このような圧電素子応用デバイスとしては、例えば次のようなものが挙げられる。 Further, another aspect of the present invention is a piezoelectric element application device including the piezoelectric element according to the above aspect. Since the piezoelectric material does not contain lead, environmental load can be reduced. In addition, since a MPB line is set up and a piezoelectric material with less temperature dependency is used, a device with less temperature dependency can be realized. In addition, since the Curie temperature is high, a device that can be used in a wide temperature range can be realized. Examples of such a piezoelectric element applied device include the following.
　ノズル開口に連通する圧力発生室と、上述した圧電素子と、を具備することを特徴とする液体噴射ヘッド。 A liquid ejecting head comprising a pressure generating chamber communicating with a nozzle opening and the piezoelectric element described above.
　上記態様の液体噴射ヘッドを具備することを特徴とする液体噴射装置。 A liquid ejecting apparatus comprising the liquid ejecting head according to the above aspect.
　上述した圧電素子を駆動することによって生じる変位を外部に伝える振動部と、発生した圧力波を外部に伝える整合層を備えたことを特徴とする超音波センサー。 An ultrasonic sensor comprising: a vibrating portion that transmits the displacement generated by driving the piezoelectric element described above to the outside; and a matching layer that transmits the generated pressure wave to the outside.
　上述した圧電素子を配した振動体と、接触する移動体とを少なくとも具備する圧電モーター。 A piezoelectric motor comprising at least a vibrating body provided with the above-described piezoelectric element and a moving body in contact with the vibrating body.
　上述した圧電素子により生じた電荷を上記電極から取り出す電極を備えたことを特徴とする発電装置。 A power generation device comprising an electrode for taking out the electric charge generated by the above-described piezoelectric element from the electrode.
本発明の圧電材料の製造方法を説明する相図。The phase diagram explaining the manufacturing method of the piezoelectric material of this invention. 圧電定数と温度との関係を示す図。The figure which shows the relationship between a piezoelectric constant and temperature. ＭＰＢライン及びキュリー温度のプロファイルの傾きと圧電特性との関係を説明するための相図。The phase diagram for demonstrating the relationship between the inclination of the profile of a MPB line and Curie temperature, and a piezoelectric characteristic. 圧電特性とキュリー温度との関係を示す図。The figure which shows the relationship between a piezoelectric characteristic and Curie temperature. 本発明の圧電材料の製造方法の実施例を説明する相図。The phase diagram explaining the Example of the manufacturing method of the piezoelectric material of this invention. 本発明の圧電材料の製造方法の実施例を説明する相図。The phase diagram explaining the Example of the manufacturing method of the piezoelectric material of this invention. 本発明の圧電材料の製造方法の実施例を説明する相図。The phase diagram explaining the Example of the manufacturing method of the piezoelectric material of this invention. 本発明の一実施形態に係る記録ヘッドの概略構成を示す分解斜視図。1 is an exploded perspective view illustrating a schematic configuration of a recording head according to an embodiment of the invention. 本発明の一実施形態に係る記録ヘッドの平面図。1 is a plan view of a recording head according to an embodiment of the present invention. 本発明の一実施形態に係る記録ヘッドの断面図。1 is a cross-sectional view of a recording head according to an embodiment of the invention. 本発明の一実施形態に係る記録装置の概略構成を示す図。1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment of the present invention.
　以下、本発明を実施形態に基づいて詳細に説明する。先に説明したとおり、どのような成分をどのような組成で組みあわせればＭＰＢラインが立って温度依存性の少ない圧電材料が得られるのか、どのような成分をどのような組成で組みあわせれば圧電特性の高い圧電材料が得られるのか、どのような成分をどのような組成で組みあわせればキュリー温度が高い圧電材料が得られるのか、に関して明確な指標を示す知見は今まで存在しなかった。本発明は、ＭＰＢラインができるだけ立っており、温度依存性の少ない圧電材料を得るための新規な手法を提供するものである。また、この新規な手法によれば、キュリー温度が高い、あるいは圧電特性が高い圧電材料を容易に得ることが可能となる。 Hereinafter, the present invention will be described in detail based on embodiments. As explained above, what components are combined in what composition can produce a piezoelectric material with an MPB line and less temperature dependence, and what components can be combined in what composition Until now, there has been no knowledge showing a clear index as to whether a piezoelectric material with high characteristics can be obtained or what components are combined in what composition to obtain a piezoelectric material with a high Curie temperature. The present invention provides a novel method for obtaining a piezoelectric material having an MPB line standing as much as possible and having a low temperature dependency. In addition, according to this novel technique, it is possible to easily obtain a piezoelectric material having a high Curie temperature or high piezoelectric characteristics.
　なお、以下で説明する図表において、“Ｔ”は正方晶、“Ｍ”は単斜晶、“Ｒ”は菱面体晶、“Ｏ”は斜方晶、“Ｃ”は立方晶を意味するものとする。 In the charts described below, “T” means tetragonal crystal, “M” means monoclinic crystal, “R” means rhombohedral crystal, “O” means orthorhombic crystal, and “C” means cubic crystal. And
（圧電材料の製造方法）
　本発明の圧電材料の製造方法は、２つの成分を、以下のような条件で組み合わせることにより、ＭＰＢラインができるだけ立った圧電材料を実現するものである。以下、組み合わせの条件について説明する。 (Piezoelectric material manufacturing method)
The piezoelectric material manufacturing method of the present invention realizes a piezoelectric material having an MPB line standing as much as possible by combining two components under the following conditions. Hereinafter, the combination conditions will be described.
　まず、２つの成分は、いずれもペロブスカイト型構造を有する複合酸化物からなる非鉛系圧電材料である。第１成分は、菱面体晶の複合酸化物である。第１成分のキュリー温度はＴｃ１である。第２成分は、菱面体晶以外の結晶構造を持つ複合酸化物である。第２成分のキュリー温度はＴｃ２である。 First, each of the two components is a lead-free piezoelectric material made of a complex oxide having a perovskite structure. The first component is a rhombohedral complex oxide. The Curie temperature of the first component is Tc1. The second component is a complex oxide having a crystal structure other than rhombohedral. The Curie temperature of the second component is Tc2.
　第１成分として菱面体晶、第２成分として菱面体晶以外の結晶、例えば、正方晶を選定するのは、菱面体晶が最も分極軸の数が多いからである。菱面体晶は、４つの分極軸（プラス方向とマイナス方向を分けて考えた場合は８つの分極軸）を持つ、他の結晶系、例えば、正方晶、斜方晶、単斜晶、三斜晶は、全て分極軸が１つ（プラス方向とマイナス方向を分けた場合は２方向の分極軸）である。圧電体の変形は、分極の回転または分極の伸縮・収縮を伴う。よって、分極軸の数が多い方が、圧電特性が高くなると考えられる。すなわち、菱面体晶の第１成分と、それ以外の結晶構造を持つ第２成分とを組み合わせることによって、圧電特性を向上させることが可能である。 The reason why rhombohedral crystals are selected as the first component and crystals other than rhombohedral crystals, for example, tetragonal crystals, are selected as the second component because rhombohedral crystals have the largest number of polarization axes. Rhombohedral crystals have four polarization axes (eight polarization axes when considering the plus and minus directions separately), for example, tetragonal, orthorhombic, monoclinic, triclinic Crystals all have one polarization axis (two directions of polarization axes when the positive and negative directions are separated). The deformation of the piezoelectric body is accompanied by rotation of polarization or expansion / contraction / contraction of polarization. Therefore, it can be considered that the piezoelectric characteristics increase as the number of polarization axes increases. That is, it is possible to improve the piezoelectric characteristics by combining the first component of rhombohedral crystal and the second component having other crystal structure.
　また、第２に、キュリー温度Ｔｃ１の第１成分と、キュリー温度がＴｃ２の第２成分とを選定する際に、｜Ｔｃ１－Ｔｃ２｜が５０℃以下であるものを選択する。 Second, when selecting the first component having the Curie temperature Tc1 and the second component having the Curie temperature Tc2, the one having | Tc1-Tc2 | of 50 ° C. or lower is selected.
　その理由について説明する。 Explain why.
　第１成分と第２成分によって構成される圧電材料の相図を図１に示す。図１において、縦軸Ｘは温度（℃）である。横軸は、第１成分と第２成分の合計に対する第２成分のモル比ｘ（（第２成分のモル数）／（第１成分のモル数＋第２成分のモル数））である。図１の相図は、菱面体晶で構成される組成範囲（図では“Ｒ”と表示）と正方晶（図ではＴと表示）または斜方晶（図では“Ｏ”と表示）と立方晶（図では“Ｃ”と表示）で構成されている。図１には、｜Ｔｃ１－Ｔｃ２｜の値が大きい（５０℃より大きい）組成系のキュリー温度のプロファイルを実線で、｜Ｔｃ１－Ｔｃ２｜の値が小さい（５０℃以下である）組成系のキュリー温度のプロファイルを点線で示している。｜Ｔｃ１－Ｔｃ２｜の値が大きい組成系のＭＰＢラインｍは、縦軸に対して傾斜している。ＭＰＢラインｍは、図中左側、つまり、Ｔｃが低い第１成分の比率が大きい方に傾いている。 FIG. 1 shows a phase diagram of a piezoelectric material composed of a first component and a second component. In FIG. 1, the vertical axis X is temperature (° C.). The horizontal axis represents the molar ratio of the second component to the total of the first component and the second component x ((number of moles of the second component) / (number of moles of the first component + number of moles of the second component)). The phase diagram of FIG. 1 shows a composition range (indicated as “R” in the figure) composed of rhombohedral crystals and tetragonal (indicated as T in the figure) or orthorhombic (indicated as “O” in the figure) and cubic. It is composed of crystals (indicated as “C” in the figure). FIG. 1 shows a Curie temperature profile of a composition system with a large value of | Tc1-Tc2 | (greater than 50 ° C.) as a solid line, and a composition system with a small value of | Tc1-Tc2 | (less than 50 ° C.). The Curie temperature profile is indicated by a dotted line. The MPB line m of the composition system having a large value of | Tc1-Tc2 | is inclined with respect to the vertical axis. The MPB line m is inclined to the left side in the figure, that is, to the side where the ratio of the first component having a low Tc is large.
　そこで、｜Ｔｃ１－Ｔｃ２｜が５０℃以下となるように、第１成分と第２成分とを選択すると、キュリー温度のプロファイルは図１中点線で示したように水平に近くなり、ＭＰＢラインＭの傾きが小さくなり、ＭＰＢラインＭが立った圧電材料を得ることが可能となる。図１において、点線のプロファイルのうち、両端を除いた部分は、２つの成分からなる圧電材料（２成分系圧電材料）のキュリー温度Ｔｃ３を示している。この点線のプロファイルから理解できるように、｜Ｔｃ１－Ｔｃ２｜が５０℃以下となるように第１成分と第２成分とを選択することによって得られた２成分系圧電材料のキュリー温度Ｔｃ３は、横軸全域に亘って高くなる。 Therefore, when the first component and the second component are selected so that | Tc1-Tc2 | is 50 ° C. or less, the Curie temperature profile becomes almost horizontal as shown by the dotted line in FIG. 1, and the MPB line M It becomes possible to obtain a piezoelectric material in which the MPB line M stands. In FIG. 1, the portion of the dotted profile excluding both ends indicates the Curie temperature Tc3 of a piezoelectric material (two-component piezoelectric material) composed of two components. As can be understood from the dotted line profile, the Curie temperature Tc3 of the two-component piezoelectric material obtained by selecting the first component and the second component so that | Tc1-Tc2 | It becomes higher over the entire horizontal axis.
　ここで、圧電材料の圧電定数は、当該材料の組成によって変化する。すなわち、圧電特性は組成依存性を有する。ＭＰＢライン上の組成（ＭＰＢ組成）において、圧電定数は極大値をとる。よって、特性の高い圧電材料を得るためには、３つの成分を上記の条件で組み合わせ、かつＭＰＢ近傍の組成をとることが好ましい。本発明においては、圧電定数が、室温（２０℃以上２５℃以下の範囲内における任意の温度）におけるＭＰＢ組成の圧電定数に対して７０％以上の範囲内である組成領域を、ＭＰＢ近傍の組成と定義する。図１では、ＭＰＢ近傍の組成をハッチングで示している。 Here, the piezoelectric constant of the piezoelectric material varies depending on the composition of the material. That is, the piezoelectric characteristics have composition dependency. In the composition on the MPB line (MPB composition), the piezoelectric constant takes a maximum value. Therefore, in order to obtain a piezoelectric material with high characteristics, it is preferable to combine the three components under the above conditions and to have a composition near the MPB. In the present invention, a composition region in which the piezoelectric constant is within a range of 70% or more with respect to the piezoelectric constant of the MPB composition at room temperature (any temperature within a range of 20 ° C. or more and 25 ° C. or less) is a composition near the MPB. It is defined as In FIG. 1, the composition in the vicinity of the MPB is shown by hatching.
　また、図２に示すように、圧電特性は、その組成に関わらず、キュリー温度で最も高く、キュリー温度から低温側へ離れるほど低くなる。そして、圧電特性の温度変化は、キュリー温度付近では急峻であり、キュリー温度から低温側に離れた領域では緩やかである。この様子を、相図内に等高線にして示したものが、図３（ａ）及び（ｂ）である。図３（ａ）は、キュリー温度Ｔｃ１とＴｃ２の差の絶対値が大きく、ＭＰＢラインｍが傾斜している場合の相図である。図３（ｂ）は、キュリー温度Ｔｃ１とＴｃ２の差の絶対値が小さく、ＭＰＢラインＭが立っている場合の相図である。これらの図において、等高線は、圧電定数（ｄ３３）の高さを示したものである。実際の圧電材料におけるＭＰＢラインｍ及びＭは直線ではなく、また、等高線も円形ではないが、図３（ａ）及び（ｂ）では、説明を理解しやすくするために、これらを単純化して示している。また、キュリー温度のプロファイル（図３（ａ）の実線及び図３（ｂ）の点線のプロファイル）も、より簡略化した状態で示している。なお、図中Ｔｕは、圧電材料の使用温度範囲の上限値を示す。 Further, as shown in FIG. 2, the piezoelectric characteristics are highest at the Curie temperature regardless of the composition, and become lower as the temperature goes away from the Curie temperature. The temperature change of the piezoelectric characteristics is steep near the Curie temperature, and is gentle in a region away from the Curie temperature to the low temperature side. FIGS. 3A and 3B show this state as contour lines in the phase diagram. FIG. 3A is a phase diagram when the absolute value of the difference between the Curie temperatures Tc1 and Tc2 is large and the MPB line m is inclined. FIG. 3B is a phase diagram when the absolute value of the difference between the Curie temperatures Tc1 and Tc2 is small and the MPB line M is standing. In these figures, contour lines indicate the height of the piezoelectric constant (d33). The MPB lines m and M in the actual piezoelectric material are not straight lines, and the contour lines are not circular. However, in FIGS. 3A and 3B, these are simplified for easy understanding of the explanation. ing. Further, the Curie temperature profile (the solid line profile in FIG. 3A and the dotted line profile in FIG. 3B) is also shown in a more simplified state. In the figure, Tu represents the upper limit of the operating temperature range of the piezoelectric material.
　図３（ａ）において、２５℃におけるＭＰＢ組成をＰｍ０、ＭＰＢ組成Ｐｍ０から第２成分の割合が少なくなる方向（図中左側）にずれた組成をＰｍ１、ＭＰＢ組成Ｐｍ０から第２成分の割合が多くなる方向（図中右側）にずれた組成をＰｍ２として示す。図３（ｂ）において、２５℃におけるＭＰＢ組成をＰＭ０、ＭＰＢ組成ＰＭ０から第２成分の割合が少なくなる方向（図中左側）にずれた組成をＰＭ１、ＭＰＢ組成ＰＭ０から第２成分の割合が多くなる方向（図中右側）にずれた組成をＰＭ２として示す。図３（ａ）の相図では、環境温度が変化した場合、図中矢印で示したように、Ｐｍ０とＰｍ１とＰｍ２とでは、圧電特性の変動傾向（温度依存性の傾向）がかなり異なってしまう。一方、図３（ｂ）の相図では、環境温度が変化しても、図中矢印で示したように、ＰＭ０とＰＭ１とＰＭ２とでは、圧電特性の変動傾向（温度依存性の傾向）はあまり変化しない。つまり、図３（ｂ）に示したように、ＭＰＢラインが立っており、Ｔｃ１とＴｃ２との絶対値の差が小さければ、組成がずれたとしても、温度依存性の傾向の変化が起こりにくいと言える。実際に、圧電材料を用いて圧電素子を製造する際のことを考えると、理想的な組成（たとえば２５℃におけるＭＰＢ組成）を目標として圧電素子を製造しても、最終的にはその組成からずれてしまうことが多い。よって、ＭＰＢラインがなるべく立った圧電材料を利用することで、組成の誤差が発生したとしても圧電特性の温度依存性の傾向の変化が少なくなり、特性のばらつきが少ない圧電素子を得ることが可能となる。なお、ここで説明した圧電特性の温度依存性の傾向の変化も、「温度依存性」の一種と考えることができる。 In FIG. 3A, the MPB composition at 25 ° C. is Pm0, the composition shifted from the MPB composition Pm0 in the direction in which the ratio of the second component decreases (left side in the figure) is Pm1, and the ratio of the second component from the MPB composition Pm0 is The composition shifted in the increasing direction (right side in the figure) is shown as Pm2. In FIG. 3 (b), the MPB composition at 25 ° C. is PM0, the composition shifted from the MPB composition PM0 in the direction in which the ratio of the second component decreases (left side in the figure) is PM1, and the ratio of the second component from the MPB composition PM0 is The composition shifted in the increasing direction (right side in the figure) is shown as PM2. In the phase diagram of FIG. 3A, when the environmental temperature changes, as shown by the arrows in the figure, the fluctuation tendency (temperature dependence tendency) of the piezoelectric characteristics is significantly different among Pm0, Pm1, and Pm2. End up. On the other hand, in the phase diagram of FIG. 3 (b), even if the environmental temperature changes, as shown by the arrows in the figure, the fluctuation tendency (temperature dependence tendency) of the piezoelectric characteristics is between PM0, PM1, and PM2. Does not change much. That is, as shown in FIG. 3B, if the MPB line is standing and the difference between the absolute values of Tc1 and Tc2 is small, even if the composition is deviated, the temperature-dependent tendency hardly changes. It can be said. Actually, when considering the case of manufacturing a piezoelectric element using a piezoelectric material, even if a piezoelectric element is manufactured with an ideal composition (for example, MPB composition at 25 ° C.) as a target, it is finally determined from the composition. Often slips. Therefore, by using a piezoelectric material with the MPB line standing as much as possible, even if a composition error occurs, the change in the temperature dependence tendency of the piezoelectric characteristics is reduced, and a piezoelectric element with little variation in characteristics can be obtained. It becomes. Note that the change in the temperature dependency tendency of the piezoelectric characteristics described here can also be considered as a kind of “temperature dependency”.
　また、図３（ａ）では等高線をかなり単純化して示しているが、実際は、どのような組成においても、図２に示したように、キュリー温度Ｔｃ付近における圧電定数（ｄ３３）の変化が急峻となり、キュリー温度から低温側に離れた領域では緩やかである。よって、使用温度の上限値Ｔｕに対して、キュリー温度Ｔｃは十分に高いことが好ましい。例えば、使用温度の上限値Ｔｕに対して５０℃以上、より好ましくは１００℃以上高いことが好ましい。また、キュリー温度Ｔｃは、組成範囲全体に亘って高い方が好ましい。図１からわかるように、本発明によって得られる２成分系圧電材料は、どのような組成をとってもキュリー温度Ｔｃ３が高い。よって、このような点からも、組成の誤差に起因する圧電特性の温度依存性の傾向の変化が少ないと言える。 In FIG. 3A, the contour lines are considerably simplified. Actually, however, the change in the piezoelectric constant (d33) near the Curie temperature Tc is steep as shown in FIG. 2 in any composition. Thus, it is gentle in the region away from the Curie temperature to the low temperature side. Therefore, it is preferable that the Curie temperature Tc is sufficiently higher than the upper limit Tu of the use temperature. For example, it is preferably 50 ° C. or more, more preferably 100 ° C. or more higher than the upper limit value Tu of the use temperature. The Curie temperature Tc is preferably higher over the entire composition range. As can be seen from FIG. 1, the two-component piezoelectric material obtained by the present invention has a high Curie temperature Tc3 regardless of the composition. Therefore, from this point, it can be said that there is little change in the temperature dependence tendency of the piezoelectric characteristics due to the composition error.
　２成分系圧電材料のキュリー温度Ｔｃ３は、圧電材料の一般的な用途を考慮すると、２８０℃以上であれば十分である。つまり、キュリー温度Ｔｃ３を２８０℃以上とすることで、汎用性が非常に高い圧電材料を提供することが可能となる。キュリー温度Ｔｃ３は、ＭＰＢ近傍の組成だけでなく、ほぼ全体の組成領域、たとえば第１成分と第２成分との合計に対する第２成分のモル比ｘが０．１以上０．９以下の部分において、２８０℃以上であることが好ましい。このような２成分系圧電材料であれば、どのような組成をとってもキュリー温度が十分に高くなり、組成の誤差に起因する圧電特性の温度依存性の傾向の変化をかなり小さく抑えることが可能となる。 It is sufficient that the Curie temperature Tc3 of the two-component piezoelectric material is 280 ° C. or higher in consideration of general use of the piezoelectric material. That is, by setting the Curie temperature Tc3 to 280 ° C. or higher, it is possible to provide a piezoelectric material with very high versatility. The Curie temperature Tc3 is not limited to the composition in the vicinity of the MPB, but in almost the entire composition region, for example, in the portion where the molar ratio x of the second component to the sum of the first component and the second component is 0.1 or more and 0.9 or less. It is preferable that it is 280 degreeC or more. With such a two-component piezoelectric material, the Curie temperature is sufficiently high regardless of the composition, and the change in the temperature dependence tendency of the piezoelectric characteristics due to the composition error can be suppressed to a very small level. Become.
　ただし、本発明では、第２成分のモル比ｘが０．１以上０．９以下の組成範囲すべてで、キュリー温度Ｔｃ３が２８０℃以上となるような条件を満足することは必須ではない。第２成分のモル比ｘが０．１以上０．９以下の組成範囲のうち、一部において、キュリー温度Ｔｃ３が２８０℃に達していない領域がある場合は、キュリー温度Ｔｃ３が２８０℃以上に位置する領域の組成を選択する。たとえば、ＭＰＢ近傍の組成を利用したい場合には、少なくともＭＰＢ近傍の組成において、キュリー温度Ｔｃ３が２８０℃以上となるような条件で、第１成分と第２成分とを選択すれば良い。 However, in the present invention, it is not essential to satisfy the condition that the Curie temperature Tc3 is 280 ° C. or higher in the entire composition range where the molar ratio x of the second component is 0.1 or higher and 0.9 or lower. In a part of the composition range where the molar ratio x of the second component is 0.1 or more and 0.9 or less, when there is a region where the Curie temperature Tc3 does not reach 280 ° C., the Curie temperature Tc 3 becomes 280 ° C. or more. The composition of the located region is selected. For example, when the composition near the MPB is desired to be used, the first component and the second component may be selected under the condition that the Curie temperature Tc3 is 280 ° C. or higher in the composition near the MPB.
　（第１成分及び第２成分）
　第１成分は、単独組成では菱面体晶である。このようなペロブスカイト型複合酸化物の例を、表１に示す。 (First component and second component)
The first component is rhombohedral in the single composition. Examples of such perovskite complex oxides are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　また、第２成分は、単独組成では菱面体晶以外の結晶である。このようなペロブスカイト型複合酸化物の例を、表２に示す。 Further, the second component is a crystal other than rhombohedral crystals in a single composition. Examples of such perovskite complex oxides are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　第１成分と第２成分とは、異なる材料系であることが好ましい。例えば、第１成分がＢｉ系の成分である場合、第２成分はＮｂ系の成分であることが好ましい。また、例えば、第１成分がＢａ系の成分である場合、第２成分はＮｂ系の成分であることが好ましい。図４は、圧電材料の圧電特性（ｄ３３）とキュリー温度との関係を示す図である。図４に示すように、圧電材料の圧電特性（ｄ３３）とキュリー温度との関係は、Ａサイトにバリウムを含むＢａ系、Ｂサイトにニオブを含むＮｂ系、及び、Ａサイトにビスマスを含むＢｉ系の３種類に分類される。また、異なる材料系、例えばＢｉ系の成分とＮｂ系の成分とを組み合わせると、図４中点線で示したように、キュリー温度Ｔｃは両者の間の中間の値となり、圧電特性（ｄ３３）は、ＭＰＢライン近傍で極大値をとることから、図４中実線で示したように、両者の大きい方の値を上回る値をとることが予想される。同じ系の材料を２種類組み合わせても、同様のことが言える。しかし、異なる系に属する材料は、異なる特長を持つことが多い。よって、異なる系に属する材料同士を組み合わせると、それぞれの材料が持つ長所が活かされ、より実用性に優れた圧電材料を得ることが可能となる。 The first component and the second component are preferably different material systems. For example, when the first component is a Bi-based component, the second component is preferably an Nb-based component. For example, when the first component is a Ba-based component, the second component is preferably an Nb-based component. FIG. 4 is a graph showing the relationship between the piezoelectric characteristics (d33) of the piezoelectric material and the Curie temperature. As shown in FIG. 4, the relationship between the piezoelectric properties (d33) of the piezoelectric material and the Curie temperature is as follows: Ba system containing barium at the A site, Nb system containing niobium at the B site, and Bi containing bismuth at the A site. There are three types of systems. Also, when different material systems, for example, Bi-based components and Nb-based components are combined, the Curie temperature Tc becomes an intermediate value between the two as shown by the dotted line in FIG. 4, and the piezoelectric characteristic (d33) is Since the maximum value is taken in the vicinity of the MPB line, it is expected that the value exceeds the larger value of both as shown by the solid line in FIG. The same can be said when two kinds of materials of the same system are combined. However, materials belonging to different systems often have different characteristics. Therefore, when materials belonging to different systems are combined, the advantages of the respective materials are utilized, and a piezoelectric material with more practicality can be obtained.
（実施例）
　以下、実施例を説明する。実施例の説明（表３を含む）において、キュリー温度Ｔｃ３の値は、第１成分と第２成分の合計に対する第２成分もモル比ｘ＝０．５の組成における値である。本発明では、第１成分のキュリー温度Ｔｃ１と第２成分のキュリー温度Ｔｃ２との差の絶対値が５０℃以内であり、ＭＰＢラインがなるべく立った状態であるため、ＭＰＢ組成付近のキュリー温度は、以下に示したＴｃ３の値と大きくは異ならないはずである。 (Example)
Examples will be described below. In the description of the examples (including Table 3), the value of the Curie temperature Tc3 is a value in the composition of the molar ratio x = 0.5 for the second component with respect to the total of the first component and the second component. In the present invention, since the absolute value of the difference between the Curie temperature Tc1 of the first component and the Curie temperature Tc2 of the second component is within 50 ° C. and the MPB line is as standing as possible, the Curie temperature near the MPB composition is The value of Tc3 shown below should not be significantly different.
（実施例１）
　図５に、第１成分として（Ｂｉ，Ｎａ，Ｌａ）ＴｉＯ３、第２成分としてＮａＮｂＯ３を選択して組み合わせた相図を示す。第１成分である（Ｂｉ，Ｎａ，Ｌａ）ＴｉＯ３は、単独では菱面体晶であり、そのキュリー温度Ｔｃ１は３３５℃である。第２成分であるＮａＮｂＯ３は、単独では正方晶であり、キュリー温度Ｔｃ２は３６５℃である。従って、｜Ｔｃ１－Ｔｃ２｜≦５０℃の条件を満たしている。また、｜Ｔｃ１－Ｔｃ２｜／｜Ｔｃ１＋Ｔｃ２｜≦０．１の条件をも満たしている。ＭＰＢラインＭ１は、ほぼ垂直に立ち、第２成分の組成比が０．５～０．６に亘る範囲で変化するだけである。キュリー温度Ｔｃ３は３５０℃である。本実施例では、第１成分と第２成分との合計に対する第２成分のモル比ｘが０．１以上０．９以下の組成範囲全域で、キュリー温度Ｔｃ３が２８０℃以上であるため、第２成分とのモル比ｘは０．１以上０．９以下の範囲内で選択することが可能である。特に、ＭＰＢ近傍の組成を有するように第１成分と第２成分とを組み合わせれば、圧電特性の高い圧電材料が得られる。 (Example 1)
Figure 5 shows as a first component (Bi, Na, La) TiO 3, a phase diagram of a combination by selecting NaNbO 3 as the second component. The first component (Bi, Na, La) TiO 3 is a rhombohedral crystal alone, and its Curie temperature Tc1 is 335 ° C. NaNbO 3 as the second component alone is tetragonal and has a Curie temperature Tc2 of 365 ° C. Therefore, the condition of | Tc1-Tc2 | ≦ 50 ° C. is satisfied. Also, the condition of | Tc1-Tc2 | / | Tc1 + Tc2 | ≦ 0.1 is satisfied. The MPB line M1 stands almost vertically and only changes in a range where the composition ratio of the second component ranges from 0.5 to 0.6. The Curie temperature Tc3 is 350 ° C. In this example, the Curie temperature Tc3 is 280 ° C. or higher over the entire composition range where the molar ratio x of the second component to the total of the first component and the second component is 0.1 to 0.9. The molar ratio x with the two components can be selected within the range of 0.1 or more and 0.9 or less. In particular, when the first component and the second component are combined so as to have a composition near the MPB, a piezoelectric material having high piezoelectric characteristics can be obtained.
　一例として、第１成分として（Ｂｉ０．５，Ｎａ０．４，Ｌａ０．１）ＴｉＯ３、第２成分としてＮａＮｂＯ３を選定し、両者のモル比を０．４０：０．６０とした組成の圧電材料によって、圧電体層を形成するための方法を説明する。 As an example, as a first component (Bi 0.5, Na 0.4, La 0.1) TiO 3, as a second component selected NaNbO 3, both molar ratio of 0.40: to 0.60 A method for forming a piezoelectric layer with a piezoelectric material having a composition will be described.
　出発原料として、２－エチルへキサン酸ビスマス、２－エチルへキサン酸ナトリウム、２－エチルへキサン酸ランタン、２－エチルへキサン酸チタン、２－エチルへキサン酸ニオブを、ｎ－オクタン溶液に、上記組成の化学量論比と一致するように金属元素のモル比を調整して混合し、前駆体溶液を作製する。 As starting materials, bismuth 2-ethylhexanoate, sodium 2-ethylhexanoate, lanthanum 2-ethylhexanoate, titanium 2-ethylhexanoate, niobium 2-ethylhexanoate in an n-octane solution Then, the molar ratio of the metal elements is adjusted and mixed so as to coincide with the stoichiometric ratio of the above composition to prepare a precursor solution.
　このような前駆体溶液を、基板上に滴下し、５００ｒｐｍで６秒間回転後、３０００ｒｐｍで基板を２０秒回転させてスピンコート法により前駆体膜を形成する。次に、ホットプレート上に基板を載せ、１８０℃で２分間乾燥する。次いで、ホットプレート上に基板を載せ、３５０℃で２分間脱脂を行う。この溶液塗布から脱脂までの工程を２回繰り返した後に、酸素雰囲気中で、ＲＴＡ装置で、７５０℃で５分間焼成を行う。以上の工程を５回繰り返すことにより、圧電体層が完成する。 Such a precursor solution is dropped on a substrate, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating. Next, the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes. Next, the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes. After repeating this process from solution application to degreasing twice, baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus. By repeating the above process five times, the piezoelectric layer is completed.
（実施例２）
　図６には、第１成分として（Ｂｉ，Ｎａ，Ｌａ）ＴｉＯ３、第２成分としてＬｉとＴａを添加した（Ｋ，Ｎａ）ＮｂＯ３を選択して組み合わせた相図を示す。第１成分である（Ｂｉ，Ｎａ，Ｌａ）ＴｉＯ３は、単独では菱面体晶であり、そのキュリー温度Ｔｃ１は３３５℃である。第２成分であるＬｉとＴａを添加した（Ｋ，Ｎａ）ＮｂＯ３は、単独では斜方晶であり、そのキュリー温度Ｔｃは３２５℃である。従って、｜Ｔｃ１－Ｔｃ２｜≦５０℃の条件を満たしている。また、｜Ｔｃ１－Ｔｃ２｜／｜Ｔｃ１＋Ｔｃ２｜≦０．１の条件をも満たしている。ＭＰＢラインＭ２は、ほぼ垂直に立ち、第２成分の組成比が０．４６～０．６３の範囲で変化するだけである。キュリー温度Ｔｃ３は３３０℃である。本実施例では、第１成分と第２成分との合計に対する第２成分のモル比ｘが０．１以上０．９以下の組成範囲全域で、キュリー温度Ｔｃ３が２８０℃以上であるため、第２成分とのモル比ｘは０．１以上０．９以下の範囲内で選択することが可能である。特に、ＭＰＢ近傍の組成を有するように第１成分と第２成分とを組み合わせれば、圧電特性の高い圧電材料が得られる。 (Example 2)
FIG. 6 shows a phase diagram in which (Bi, Na, La) TiO 3 is selected as the first component and (K, Na) NbO 3 to which Li and Ta are added as the second component is selected and combined. The first component (Bi, Na, La) TiO 3 is a rhombohedral crystal alone, and its Curie temperature Tc1 is 335 ° C. (K, Na) NbO 3 to which Li and Ta as the second component are added is orthorhombic alone, and its Curie temperature Tc is 325 ° C. Therefore, the condition of | Tc1-Tc2 | ≦ 50 ° C. is satisfied. Also, the condition of | Tc1-Tc2 | / | Tc1 + Tc2 | ≦ 0.1 is satisfied. The MPB line M2 stands almost vertically and only changes in the range of the composition ratio of the second component from 0.46 to 0.63. The Curie temperature Tc3 is 330 ° C. In this example, the Curie temperature Tc3 is 280 ° C. or higher over the entire composition range where the molar ratio x of the second component to the total of the first component and the second component is 0.1 to 0.9. The molar ratio x with the two components can be selected within the range of 0.1 or more and 0.9 or less. In particular, when the first component and the second component are combined so as to have a composition near the MPB, a piezoelectric material having high piezoelectric characteristics can be obtained.
　一例として、第１成分として（Ｂｉ０．５，Ｎａ０．４，Ｌａ０．１）ＴｉＯ３、第２成分としてＬｉとＴａを添加した（Ｋ０．５，Ｎａ０．５）ＮｂＯ３を選定し、両者のモル比を０．３７：０．６３とした組成の圧電材料によって、圧電体層を形成するための方法を説明する。 As an example, (Bi 0.5 , Na 0.4 , La 0.1 ) TiO 3 as the first component, and (K 0.5 , Na 0.5 ) NbO 3 with Li and Ta added as the second component. A method for forming a piezoelectric layer with a piezoelectric material having a composition selected and having a molar ratio of 0.37: 0.63 will be described.
　出発原料として、２－エチルへキサン酸ビスマス、２－エチルへキサン酸ナトリウム、２－エチルへキサン酸ランタン、２－エチルへキサン酸チタン、２－エチルへキサン酸カリウム、２－エチルへキサン酸ニオブ、２－エチルへキサン酸リチウム、２－エチルへキサン酸タンタルを、ｎ－オクタン溶液に、上記組成の化学量論比と一致するように金属元素のモル比を調整して混合し、前駆体溶液を作製する。 Starting materials include bismuth 2-ethylhexanoate, sodium 2-ethylhexanoate, lanthanum 2-ethylhexanoate, titanium 2-ethylhexanoate, potassium 2-ethylhexanoate, 2-ethylhexanoic acid Niobium, lithium 2-ethylhexanoate, and tantalum 2-ethylhexanoate are mixed in an n-octane solution with the molar ratio of the metal elements adjusted so as to match the stoichiometric ratio of the above composition. Make a body solution.
　このような前駆体溶液を、基板上に滴下し、５００ｒｐｍで６秒間回転後、３０００ｒｐｍで基板を２０秒回転させてスピンコート法により前駆体膜を形成する。次に、ホットプレート上に基板を載せ、１８０℃で２分間乾燥する。次いで、ホットプレート上に基板を載せ、３５０℃で２分間脱脂を行う。この溶液塗布から脱脂までの工程を２回繰り返した後に、酸素雰囲気中で、ＲＴＡ装置で、７５０℃で５分間焼成を行う。以上の工程を５回繰り返すことにより、圧電体層が完成する。 Such a precursor solution is dropped on a substrate, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating. Next, the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes. Next, the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes. After repeating this process from solution application to degreasing twice, baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus. By repeating the above process five times, the piezoelectric layer is completed.
（実施例３）
　図７には、第１成分として（Ｂｉ，Ｎａ，Ｌａ）ＴｉＯ３、第２成分として（Ｂｉ，Ｋ）ＴｉＯ３を選択して組み合わせた相図を示す。第１成分である（Ｂｉ，Ｎａ，Ｌａ）ＴｉＯ３は、単独では菱面体晶であり、そのキュリー温度Ｔｃ１は３３５℃である。第２成分である（Ｂｉ，Ｋ）ＴｉＯ３は、単独では正方晶であり、そのキュリー温度Ｔｃは３８０℃である。従って、｜Ｔｃ１－Ｔｃ２｜≦５０℃の条件を満たしている。また、｜Ｔｃ１－Ｔｃ２｜／｜Ｔｃ１＋Ｔｃ２｜≦０．１の条件をも満たしている。ＭＰＢラインＭ３は、ほぼ垂直に立ち、第２成分の組成比が０．３１～０．３５の範囲で変化するだけである。また、キュリー温度Ｔｃ３は３５７．５℃である。本実施例では、第１成分と第２成分との合計に対する第２成分のモル比ｘが０．１以上０．９以下の組成範囲全域で、キュリー温度Ｔｃ３が２８０℃以上であるため、第２成分とのモル比ｘは０．１以上０．９以下の範囲内で選択することが可能である。特に、ＭＰＢ近傍の組成を有するように第１成分と第２成分とを組み合わせれば、圧電特性の高い圧電材料が得られる。 (Example 3)
Figure 7 shows as a first component (Bi, Na, La) TiO 3, as the second component (Bi, K) phase diagram which is a combination by selecting TiO 3. The first component (Bi, Na, La) TiO 3 is a rhombohedral crystal alone, and its Curie temperature Tc1 is 335 ° C. The second component (Bi, K) TiO 3 alone is a tetragonal crystal, and its Curie temperature Tc is 380 ° C. Therefore, the condition of | Tc1-Tc2 | ≦ 50 ° C. is satisfied. Also, the condition of | Tc1-Tc2 | / | Tc1 + Tc2 | ≦ 0.1 is satisfied. The MPB line M3 stands substantially vertically and only changes in the range of the composition ratio of the second component from 0.31 to 0.35. The Curie temperature Tc3 is 357.5 ° C. In this example, the Curie temperature Tc3 is 280 ° C. or higher over the entire composition range where the molar ratio x of the second component to the total of the first component and the second component is 0.1 to 0.9. The molar ratio x with the two components can be selected within the range of 0.1 or more and 0.9 or less. In particular, when the first component and the second component are combined so as to have a composition near the MPB, a piezoelectric material having high piezoelectric characteristics can be obtained.
　一例として、第１成分として（Ｂｉ０．５，Ｎａ０．４，Ｌａ０．１）ＴｉＯ３、第２成分として（Ｂｉ０．５，Ｋ０．５）ＴｉＯ３を選定し、両者のモル比を０．６５:０．３５とした組成の圧電材料によって、圧電体層を形成するための方法を説明する。 As an example, as a first component (Bi 0.5, Na 0.4, La 0.1) TiO 3, as the second component (Bi 0.5, K 0.5) selects the TiO 3, both molar A method for forming a piezoelectric layer with a piezoelectric material having a composition of 0.65: 0.35 will be described.
　出発原料として、２－エチルへキサン酸ビスマス、２－エチルへキサン酸ナトリウム、２－エチルへキサン酸ランタン、２－エチルへキサン酸チタン、２－エチルへキサン酸カリウムを、ｎ－オクタン溶液に、上記組成の化学量論比と一致するように金属元素のモル比を調整して混合し、前駆体溶液を作製する。 As starting materials, bismuth 2-ethylhexanoate, sodium 2-ethylhexanoate, lanthanum 2-ethylhexanoate, titanium 2-ethylhexanoate, potassium 2-ethylhexanoate in an n-octane solution Then, the molar ratio of the metal elements is adjusted and mixed so as to coincide with the stoichiometric ratio of the above composition to prepare a precursor solution.
　このような前駆体溶液を、基板上に滴下し、５００ｒｐｍで６秒間回転後、３０００ｒｐｍで基板を２０秒回転させてスピンコート法により前駆体膜を形成する。次に、ホットプレート上に基板を載せ、１８０℃で２分間乾燥する。次いで、ホットプレート上に基板を載せ、３５０℃で２分間脱脂を行う。この溶液塗布から脱脂までの工程を２回繰り返した後に、酸素雰囲気中で、ＲＴＡ装置で、７５０℃で５分間焼成を行う。以上の工程を５回繰り返すことにより、圧電体層が完成する。 Such a precursor solution is dropped on a substrate, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating. Next, the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes. Next, the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes. After repeating this process from solution application to degreasing twice, baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus. By repeating the above process five times, the piezoelectric layer is completed.
（その他の実施形態）
　相図及び具体的な製法の説明は省略するが、上記以外の組み合わせも可能である。表３～表５に、上記の実施例１～３を含め、第１成分と第２成分の組合せの実施例を示す。 (Other embodiments)
A phase diagram and description of a specific manufacturing method are omitted, but combinations other than the above are possible. Tables 3 to 5 show examples of combinations of the first component and the second component, including Examples 1 to 3 described above.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　（圧電素子、液体噴射ヘッド）
　図８は、本発明の一実施形態に係る圧電素子を具備する液体噴射ヘッドの一例であるインクジェット式記録ヘッドの概略構成を示す分解斜視図であり、図９は、図８の平面図であり、図１０は図９のＡ－Ａ′線断面図である。図８～図１０に示すように、本実施形態の流路形成基板１０は、シリコン単結晶基板からなり、その一方の面には二酸化シリコンからなる弾性膜５０が形成されている。 (Piezoelectric element, liquid jet head)
FIG. 8 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid jet head including a piezoelectric element according to an embodiment of the present invention, and FIG. 9 is a plan view of FIG. 10 is a cross-sectional view taken along line AA ′ of FIG. As shown in FIGS. 8 to 10, the flow path forming substrate 10 of this embodiment is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.
　流路形成基板１０には、複数の圧力発生室１２がその幅方向に並設されている。また、流路形成基板１０の圧力発生室１２の長手方向外側の領域には連通部１３が形成され、連通部１３と各圧力発生室１２とが、各圧力発生室１２毎に設けられたインク供給路１４及び連通路１５を介して連通されている。連通部１３は、後述する保護基板のマニホールド部３１と連通して各圧力発生室１２の共通のインク室となるマニホールドの一部を構成する。インク供給路１４は、圧力発生室１２よりも狭い幅で形成されており、連通部１３から圧力発生室１２に流入するインクの流路抵抗を一定に保持している。なお、本実施形態では、流路の幅を片側から絞ることでインク供給路１４を形成したが、流路の幅を両側から絞ることでインク供給路を形成してもよい。また、流路の幅を絞るのではなく、厚さ方向から絞ることでインク供給路を形成してもよい。本実施形態では、流路形成基板１０には、圧力発生室１２、連通部１３、インク供給路１４及び連通路１５からなる液体流路が設けられていることになる。 The flow path forming substrate 10 has a plurality of pressure generating chambers 12 arranged in parallel in the width direction. In addition, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a supply path 14 and a communication path 15. The communication part 13 communicates with a manifold part 31 of a protective substrate, which will be described later, and constitutes a part of a manifold that becomes a common ink chamber for each pressure generating chamber 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13. In this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. In the present embodiment, the flow path forming substrate 10 is provided with a liquid flow path including the pressure generation chamber 12, the communication portion 13, the ink supply path 14, and the communication path 15.
　また、流路形成基板１０の開口面側には、各圧力発生室１２のインク供給路１４とは反対側の端部近傍に連通するノズル開口２１が穿設されたノズルプレート２０が、接着剤や熱溶着フィルム等によって固着されている。なお、ノズルプレート２０は、例えば、ガラスセラミックス、シリコン単結晶基板、ステンレス鋼等からなる。 Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.
　一方、このような流路形成基板１０の開口面とは反対側には、上述したように弾性膜５０が形成され、この弾性膜５０上には、酸化チタン等からなり、弾性膜５０等の第１電極６０の下地との密着性を向上させるための密着層５６が設けられている。なお、弾性膜５０と密着層５６との間に、必要に応じて酸化ジルコニウム等からなる絶縁体膜が形成されていてもよい。 On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the elastic film 50 is made of titanium oxide or the like. An adhesion layer 56 is provided for improving the adhesion between the first electrode 60 and the base. An insulator film made of zirconium oxide or the like may be formed between the elastic film 50 and the adhesion layer 56 as necessary.
　さらに、この密着層５６上には、第１電極６０と、厚さが２μｍ以下、好ましくは０．３～１．５μｍの薄膜である圧電体層７０と、第２電極８０とが、積層形成されて、圧電素子３００を構成している。ここで、圧電素子３００は、第１電極６０、圧電体層７０及び第２電極８０を含む部分をいう。一般的には、圧電素子３００の何れか一方の電極を共通電極とし、他方の電極及び圧電体層７０を各圧力発生室１２毎にパターニングして構成する。本実施形態では、第１電極６０を圧電素子３００の共通電極とし、第２電極８０を圧電素子３００の個別電極としているが、駆動回路や配線の都合でこれを逆にしても支障はない。また、ここでは、圧電素子３００と当該圧電素子３００の駆動により変位が生じる振動板とを合わせてアクチュエーター装置と称する。なお、上述した例では、弾性膜５０、密着層５６、第１電極６０及び必要に応じて設ける絶縁体膜が振動板として作用するが、勿論これに限定されるものではなく、例えば、弾性膜５０や密着層５６を設けなくてもよい。また、圧電素子３００自体が実質的に振動板を兼ねるようにしてもよい。 Further, on the adhesion layer 56, a first electrode 60, a piezoelectric layer 70 which is a thin film having a thickness of 2 μm or less, preferably 0.3 to 1.5 μm, and a second electrode 80 are laminated. Thus, the piezoelectric element 300 is configured. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric element 300, and the second electrode 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. Also, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50, the adhesion layer 56, the first electrode 60, and the insulator film provided as necessary function as a vibration plate. However, the present invention is not limited to this. For example, the elastic film 50 and the adhesion layer 56 may not be provided. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.
　本実施形態においては、圧電体層７０は、上述した本発明の圧電材料からなる。かかる圧電材料は、広い使用環境温度範囲で圧電特性、誘電特性が高く、また、キュリー温度が高いので、広い使用環境温度で優れた変位特性を示す圧電素子が実現できる。また、圧電材料が鉛を含有していないため、環境への負荷を低減できる。 In the present embodiment, the piezoelectric layer 70 is made of the above-described piezoelectric material of the present invention. Such a piezoelectric material has high piezoelectric characteristics and dielectric characteristics in a wide use environment temperature range, and also has a high Curie temperature, so that a piezoelectric element exhibiting excellent displacement characteristics in a wide use environment temperature can be realized. In addition, since the piezoelectric material does not contain lead, the load on the environment can be reduced.
　このような圧電素子３００の個別電極である各第２電極８０には、インク供給路１４側の端部近傍から引き出され、密着層５６上にまで延設される、例えば、金（Ａｕ）等からなるリード電極９０が接続されている。 Each second electrode 80 that is an individual electrode of the piezoelectric element 300 is drawn from the vicinity of the end on the ink supply path 14 side and extended to the adhesion layer 56, for example, gold (Au) or the like. The lead electrode 90 which consists of is connected.
　このような圧電素子３００が形成された流路形成基板１０上、すなわち、第１電極６０、密着層５６及びリード電極９０上には、マニホールド１００の少なくとも一部を構成するマニホールド部３１を有する保護基板３０が接着剤３５を介して接合されている。このマニホールド部３１は、本実施形態では、保護基板３０を厚さ方向に貫通して圧力発生室１２の幅方向に亘って形成されており、上述のように流路形成基板１０の連通部１３と連通されて各圧力発生室１２の共通のインク室となるマニホールド１００を構成している。また、流路形成基板１０の連通部１３を圧力発生室１２毎に複数に分割して、マニホールド部３１のみをマニホールドとしてもよい。さらに、例えば、流路形成基板１０に圧力発生室１２のみを設け、流路形成基板１０と保護基板３０との間に介在する部材（例えば、弾性膜５０、密着層５６等）にマニホールド１００と各圧力発生室１２とを連通するインク供給路１４を設けるようにしてもよい。 On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the first electrode 60, the adhesion layer 56, and the lead electrode 90, a protection having a manifold portion 31 constituting at least a part of the manifold 100. The substrate 30 is bonded via an adhesive 35. In this embodiment, the manifold portion 31 penetrates the protective substrate 30 in the thickness direction and is formed across the width direction of the pressure generating chamber 12. As described above, the communication portion 13 of the flow path forming substrate 10. The manifold 100 is configured as a common ink chamber for the pressure generation chambers 12. Alternatively, the communication portion 13 of the flow path forming substrate 10 may be divided into a plurality of pressure generation chambers 12 and only the manifold portion 31 may be used as a manifold. Further, for example, only the pressure generation chamber 12 is provided in the flow path forming substrate 10, and the manifold 100 is attached to a member (for example, the elastic film 50, the adhesion layer 56, etc.) interposed between the flow path forming substrate 10 and the protective substrate 30. An ink supply path 14 that communicates with each pressure generating chamber 12 may be provided.
　また、保護基板３０の圧電素子３００に対向する領域には、圧電素子３００の運動を阻害しない程度の空間を有する圧電素子保持部３２が設けられている。圧電素子保持部３２は、圧電素子３００の運動を阻害しない程度の空間を有していればよく、当該空間は密封されていても、密封されていなくてもよい。 Further, a piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 facing the piezoelectric element 300. The piezoelectric element holding part 32 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.
　このような保護基板３０としては、流路形成基板１０の熱膨張率と略同一の材料、例えば、ガラス、セラミック材料等を用いることが好ましく、本実施形態では、流路形成基板１０と同一材料のシリコン単結晶基板を用いて形成した。 As such a protective substrate 30, it is preferable to use substantially the same material as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc. In this embodiment, the same material as the flow path forming substrate 10 is used. The silicon single crystal substrate was used.
　また、保護基板３０には、保護基板３０を厚さ方向に貫通する貫通孔３３が設けられている。そして、各圧電素子３００から引き出されたリード電極９０の端部近傍は、貫通孔３３内に露出するように設けられている。 Further, the protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.
　また、保護基板３０上には、並設された圧電素子３００を駆動するための駆動回路１２０が固定されている。この駆動回路１２０としては、例えば、回路基板や半導体集積回路（ＩＣ）等を用いることができる。そして、駆動回路１２０とリード電極９０とは、ボンディングワイヤー等の導電性ワイヤーからなる接続配線１２１を介して電気的に接続されている。 Further, on the protective substrate 30, a drive circuit 120 for driving the piezoelectric elements 300 arranged in parallel is fixed. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 120. The drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 made of a conductive wire such as a bonding wire.
　また、このような保護基板３０上には、封止膜４１及び固定板４２とからなるコンプライアンス基板４０が接合されている。ここで、封止膜４１は、剛性が低く可撓性を有する材料からなり、この封止膜４１によってマニホールド部３１の一方面が封止されている。また、固定板４２は、比較的硬質の材料で形成されている。この固定板４２のマニホールド１００に対向する領域は、厚さ方向に完全に除去された開口部４３となっているため、マニホールド１００の一方面は可撓性を有する封止膜４１のみで封止されている。 Further, a compliance substrate 40 composed of a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the manifold portion 31 is sealed by the sealing film 41. The fixing plate 42 is formed of a relatively hard material. Since the area of the fixing plate 42 facing the manifold 100 is an opening 43 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 41. Has been.
　このような本実施形態のインクジェット式記録ヘッドＩでは、図示しない外部のインク供給手段と接続したインク導入口からインクを取り込み、マニホールド１００からノズル開口２１に至るまで内部をインクで満たした後、駆動回路１２０からの記録信号に従い、圧力発生室１２に対応するそれぞれの第１電極６０と第２電極８０との間に電圧を印加し、弾性膜５０、密着層５６、第１電極６０及び圧電体層７０をたわみ変形させることにより、各圧力発生室１２内の圧力が高まりノズル開口２１からインク滴が吐出する。 In such an ink jet recording head I of this embodiment, ink is taken in from an ink introduction port connected to an external ink supply means (not shown), and the interior from the manifold 100 to the nozzle opening 21 is filled with ink, and then driven. In accordance with a recording signal from the circuit 120, a voltage is applied between each of the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, and the elastic film 50, the adhesion layer 56, the first electrode 60, and the piezoelectric body. By bending and deforming the layer 70, the pressure in each pressure generation chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.
　次に、本実施形態のインクジェット式記録ヘッドの圧電素子の製造方法の一例について説明する。 Next, an example of a method for manufacturing the piezoelectric element of the ink jet recording head of this embodiment will be described.
　まず、シリコンウェハーである流路形成基板用ウェハー１１０の表面に弾性膜５０を構成する二酸化シリコン（ＳｉＯ２）等からなる二酸化シリコン膜を熱酸化等で形成する。次いで、弾性膜５０（二酸化シリコン膜）上に、酸化チタン等からなる密着層５６を、反応性スパッタ法や熱酸化等で形成する。 First, a silicon dioxide film made of silicon dioxide (SiO 2 ) or the like that constitutes the elastic film 50 is formed on the surface of the flow path forming substrate wafer 110 that is a silicon wafer by thermal oxidation or the like. Next, an adhesion layer 56 made of titanium oxide or the like is formed on the elastic film 50 (silicon dioxide film) by a reactive sputtering method, thermal oxidation, or the like.
　次に、密着層５６上に第１電極６０を形成する。具体的には、密着層５６上に白金、イリジウム、酸化イリジウム又はこれらの積層構造等からなる第１電極６０を形成する。なお、密着層５６及び第１電極６０は、例えば、スパッタリング法や蒸着法により形成することができる。 Next, the first electrode 60 is formed on the adhesion layer 56. Specifically, the first electrode 60 made of platinum, iridium, iridium oxide, or a laminated structure thereof is formed on the adhesion layer 56. The adhesion layer 56 and the first electrode 60 can be formed by, for example, a sputtering method or a vapor deposition method.
　次いで、第１電極６０上に、圧電体層７０を積層する。圧電体層７０の製造方法は特に限定されないが、例えば、有機金属化合物を溶媒に溶解・分散した溶液を塗布乾燥し、さらに高温で焼成することで金属酸化物からなる圧電体層７０を得る、ＭＯＤ（Ｍｅｔａｌ－Ｏｒｇａｎｉｃ　Ｄｅｃｏｍｐｏｓｉｔｉｏｎ）法やゾル－ゲル法等の化学溶液法を用いて圧電体層７０を形成できる。圧電体層７０は、その他、レーザーアブレーション法、スパッタリング法、パルス・レーザー・デポジション法（ＰＬＤ法）、ＣＶＤ法、エアロゾル・デポジション法などでもよい。 Next, the piezoelectric layer 70 is laminated on the first electrode 60. The method for manufacturing the piezoelectric layer 70 is not particularly limited. For example, a solution obtained by dissolving and dispersing an organometallic compound in a solvent is applied and dried, and further fired at a high temperature to obtain the piezoelectric layer 70 made of a metal oxide. The piezoelectric layer 70 can be formed using a chemical solution method such as a MOD (Metal-Organic Decomposition) method or a sol-gel method. In addition, the piezoelectric layer 70 may be a laser ablation method, a sputtering method, a pulse laser deposition method (PLD method), a CVD method, an aerosol deposition method, or the like.
　圧電体層７０を例えば、化学塗布法で形成する場合、出発原料として、所望の元素を含む２－エチルへキサン酸塩、酢酸塩等を用いる。例えば、ビスマスとバリウムと鉄とチタンを含むペロブスカイト型複合酸化物からなる圧電体層を形成したい場合は、２－エチルヘキサン酸ビスマス、２－エチルヘキサン酸バリウム、２－エチルヘキサン酸鉄、２－エチルヘキサン酸チタンなどを用いる。このような原料とｎ－オクタン溶液等の溶媒とを混合して、化学量論比と一致するように金属元素のモル比を調整して、前駆体溶液を作成する。次いで、前記前駆体溶液を、先に作製した下部電極上に滴下し、５００ｒｐｍで６秒間回転後、３０００ｒｐｍで基板を２０秒回転させてスピンコート法により前駆体膜を形成する。次に、ホットプレート上に基板を載せ、１８０℃で２分間乾燥する。次いで、ホットプレート上に基板を載せ、３５０℃で２分間脱脂を行う。この溶液塗布から脱脂までの工程を２回繰り返した後に、酸素雰囲気中で、ＲＴＡ装置で、７５０℃で５分間焼成を行う。以上の工程を５回繰り返すことにより圧電体層７０を形成することができる。 For example, when the piezoelectric layer 70 is formed by a chemical coating method, 2-ethylhexanoate or acetate containing a desired element is used as a starting material. For example, when it is desired to form a piezoelectric layer made of a perovskite complex oxide containing bismuth, barium, iron and titanium, bismuth 2-ethylhexanoate, barium 2-ethylhexanoate, iron 2-ethylhexanoate, 2- For example, titanium ethylhexanoate is used. A precursor solution is prepared by mixing such a raw material with a solvent such as an n-octane solution and adjusting the molar ratio of the metal elements so as to coincide with the stoichiometric ratio. Next, the precursor solution is dropped onto the previously prepared lower electrode, rotated at 500 rpm for 6 seconds, and then rotated at 3000 rpm for 20 seconds to form a precursor film by spin coating. Next, the substrate is placed on a hot plate and dried at 180 ° C. for 2 minutes. Next, the substrate is placed on a hot plate and degreased at 350 ° C. for 2 minutes. After repeating this process from solution application to degreasing twice, baking is performed at 750 ° C. for 5 minutes in an oxygen atmosphere in an RTA apparatus. The piezoelectric layer 70 can be formed by repeating the above steps five times.
　このように圧電体層７０を形成した後は、圧電体層７０上に白金等からなる第２電極８０をスパッタリング法等で形成し、各圧力発生室１２に対向する領域に圧電体層７０及び第２電極８０を同時にパターニングして、第１電極６０と圧電体層７０と第２電極８０からなる圧電素子３００を形成する。なお、圧電体層７０と第２電極８０とのパターニングでは、所定形状に形成したレジスト（図示なし）を介してドライエッチングすることにより一括して行うことができる。その後、必要に応じて、６００℃～８００℃の温度域でポストアニールを行ってもよい。これにより、圧電体層７０と第１電極６０や第２電極８０との良好な界面を形成することができ、かつ、圧電体層７０の結晶性を改善することができる。 After the piezoelectric layer 70 is formed in this way, the second electrode 80 made of platinum or the like is formed on the piezoelectric layer 70 by a sputtering method or the like, and the piezoelectric layer 70 and the piezoelectric layer 70 and the regions facing the pressure generation chambers 12 are formed. The second electrode 80 is simultaneously patterned to form the piezoelectric element 300 including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. The patterning of the piezoelectric layer 70 and the second electrode 80 can be performed collectively by dry etching via a resist (not shown) formed in a predetermined shape. Thereafter, post-annealing may be performed in a temperature range of 600 ° C. to 800 ° C. as necessary. Thereby, a good interface between the piezoelectric layer 70 and the first electrode 60 or the second electrode 80 can be formed, and the crystallinity of the piezoelectric layer 70 can be improved.
　次に、流路形成基板用ウェハーの全面に亘って、例えば、金（Ａｕ）等からなるリード電極９０を形成後、例えば、レジスト等からなるマスクパターンを介して各圧電素子３００毎にパターニングする。 Next, after forming a lead electrode 90 made of, for example, gold (Au) over the entire surface of the flow path forming substrate wafer, patterning is performed for each piezoelectric element 300 through a mask pattern made of, for example, a resist. .
　次に、流路形成基板用ウェハーの圧電素子３００側に、シリコンウェハーであり複数の保護基板３０となる保護基板用ウェハーを接着剤３５を介して接合した後に、流路形成基板用ウェハーを所定の厚さに薄くする。 Next, after a protective substrate wafer, which is a silicon wafer and serves as a plurality of protective substrates 30, is bonded to the piezoelectric element 300 side of the flow path forming substrate wafer via the adhesive 35, the flow path forming substrate wafer is preliminarily fixed. Reduce the thickness to.
　次に、流路形成基板用ウェハー上にマスク膜を新たに形成し、所定形状にパターニングする。 Next, a mask film is newly formed on the flow path forming substrate wafer and patterned into a predetermined shape.
　そして、流路形成基板用ウェハーをマスク膜を介してＫＯＨ等のアルカリ溶液を用いた異方性エッチング（ウェットエッチング）することにより、圧電素子３００に対応する圧力発生室１２、連通部１３、インク供給路１４及び連通路１５等を形成する。 Then, the flow path forming substrate wafer is subjected to anisotropic etching (wet etching) using an alkaline solution such as KOH through the mask film, so that the pressure generating chamber 12, the communicating portion 13, the ink corresponding to the piezoelectric element 300 is obtained. A supply path 14 and a communication path 15 are formed.
　その後は、流路形成基板用ウェハー及び保護基板用ウェハーの外周縁部の不要部分を、例えば、ダイシング等により切断することによって除去する。そして、流路形成基板用ウェハーの保護基板用ウェハーとは反対側の面のマスク膜５２を除去した後にノズル開口２１が穿設されたノズルプレート２０を接合すると共に、保護基板用ウェハーにコンプライアンス基板４０を接合し、流路形成基板用ウェハー等を図８に示すような一つのチップサイズの流路形成基板１０等に分割することによって、本実施形態のインクジェット式記録ヘッドＩとする。 Thereafter, unnecessary portions of the outer peripheral edge of the flow path forming substrate wafer and the protective substrate wafer are removed by cutting, for example, by dicing. Then, after removing the mask film 52 on the surface of the flow path forming substrate wafer opposite to the protective substrate wafer, the nozzle plate 20 having the nozzle openings 21 formed therein is joined, and the compliance substrate is attached to the protective substrate wafer. 40 is joined, and the flow path forming substrate wafer or the like is divided into a single chip size flow path forming substrate 10 or the like as shown in FIG. 8 to obtain the ink jet recording head I of this embodiment.
　以上、インクジェット式記録ヘッド及び圧電素子の一実施形態を説明したが、その構成や製法は上述したものに限定されるものではない。例えば、上述した実施形態では、基板１０として、シリコン単結晶基板を例示したが、特にこれに限定されず、例えば、ＳＯＩ基板、ガラス等の基板を用いるようにしてもよい。 As mentioned above, although one embodiment of the ink jet recording head and the piezoelectric element has been described, the configuration and manufacturing method are not limited to those described above. For example, in the above-described embodiment, a silicon single crystal substrate is exemplified as the substrate 10, but the present invention is not particularly limited thereto, and for example, a substrate such as an SOI substrate or glass may be used.
　さらに、上述した実施形態では、基板１０上に第１電極６０、圧電体層７０及び第２電極８０を順次積層した圧電素子３００を例示したが、特にこれに限定されず、例えば、圧電材料と電極形成材料とを交互に積層させて軸方向に伸縮させる縦振動型の圧電素子にも本発明を適用することができる。 Furthermore, in the above-described embodiment, the piezoelectric element 300 in which the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are sequentially laminated on the substrate 10 is illustrated, but the invention is not particularly limited thereto. The present invention can also be applied to a longitudinal vibration type piezoelectric element in which electrode forming materials are alternately stacked and expanded and contracted in the axial direction.
　圧電体層は、上述したような薄膜ではなく、バルクとしてもよい。バルクで形成する場合は、出発原料として、炭酸塩または酸化物を使用する。例えば、Ｋ２ＣＯ３、Ｎａ２ＣＯ３、およびＮｂ２Ｏ５ などである。これらの出発原料を、化学量論比と一致するように秤取して、ボールミルを用いてエタノール中で湿式混合する。得られた混合物を乾燥した後、７００℃で３ｈ仮焼する。これら仮焼粉にバインダーとしてＰＶＡを適量加えて乳鉢を用いて粉砕混合し、１５０メッシュのふるいを通して粒度調整を行い、得られた粉体を一軸プレス装置で円板状のペレットに成形する。次に、成型したペレットと仮焼粉の残りをるつぼに入れ１１００℃で３ｈ焼成し、円板状の酸化物を得る。次いで、得られた円板状酸化物の両面を研磨して表面を整え、これに銀ペーストを塗布焼付けして銀電極を具備する圧電体を得ることができる。なお、このようなバルクの製造においては、出発原料として、炭酸バリウム、酸化チタン、酸化ビスマス、酸化スズ、酸化鉄、酸化ジルコニウム、酸化ランタン、炭酸リチウムなどを挙げることができる。 The piezoelectric layer may be a bulk instead of the thin film as described above. When forming in bulk, carbonates or oxides are used as starting materials. For example, K 2 CO 3 , Na 2 CO 3 , and Nb 2 O 5 . These starting materials are weighed to match the stoichiometric ratio and wet mixed in ethanol using a ball mill. The obtained mixture is dried and calcined at 700 ° C. for 3 hours. An appropriate amount of PVA as a binder is added to these calcined powders, pulverized and mixed using a mortar, particle size adjustment is performed through a 150-mesh sieve, and the obtained powder is formed into disk-shaped pellets with a single screw press. Next, the molded pellets and the remainder of the calcined powder are placed in a crucible and fired at 1100 ° C. for 3 hours to obtain a disk-shaped oxide. Next, both surfaces of the obtained disk-shaped oxide are polished to prepare a surface, and a silver paste is applied and baked on this to obtain a piezoelectric body having a silver electrode. In such bulk production, examples of starting materials include barium carbonate, titanium oxide, bismuth oxide, tin oxide, iron oxide, zirconium oxide, lanthanum oxide, and lithium carbonate.
　また、これら実施形態のインクジェット式記録ヘッドは、インクカートリッジ等と連通するインク流路を具備する記録ヘッドユニットの一部を構成して、インクジェット式記録装置に搭載される。図１１は、そのインクジェット式記録装置の一例を示す概略図である。 In addition, the ink jet recording head of these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 11 is a schematic view showing an example of the ink jet recording apparatus.
　図１１に示すように、インクジェット式記録ヘッドＩを有する記録ヘッドユニット１Ａ及び１Ｂは、インク供給手段を構成するカートリッジ２Ａ及び２Ｂが着脱可能に設けられ、この記録ヘッドユニット１Ａ及び１Ｂを搭載したキャリッジ３は、装置本体４に取り付けられたキャリッジ軸５に軸方向移動自在に設けられている。この記録ヘッドユニット１Ａ及び１Ｂは、例えば、それぞれブラックインク組成物及びカラーインク組成物を吐出するものとしている。 As shown in FIG. 11, in the recording head units 1A and 1B having the ink jet recording head I, cartridges 2A and 2B constituting ink supply means are detachably provided, and a carriage on which the recording head units 1A and 1B are mounted. 3 is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.
　そして、駆動モーター６の駆動力が図示しない複数の歯車およびタイミングベルト７を介してキャリッジ３に伝達されることで、記録ヘッドユニット１Ａ及び１Ｂを搭載したキャリッジ３はキャリッジ軸５に沿って移動される。一方、装置本体４にはキャリッジ軸５に沿ってプラテン８が設けられており、図示しない給紙ローラーなどにより給紙された紙等の記録媒体である記録シートＳがプラテン８に巻き掛けられて搬送されるようになっている。 The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.
　図１１に示す例では、インクジェット式記録ヘッドユニット１Ａ、１Ｂは、それぞれ１つのインクジェット式記録ヘッドＩを有するものとしたが、特にこれに限定されず、例えば、１つのインクジェット式記録ヘッドユニット１Ａ又は１Ｂが２以上のインクジェット式記録ヘッドを有するようにしてもよい。 In the example shown in FIG. 11, each of the ink jet recording head units 1A and 1B has one ink jet recording head I. However, the present invention is not particularly limited to this. For example, one ink jet recording head unit 1A or 1 1B may have two or more ink jet recording heads.
　なお、上述した実施形態では、液体噴射ヘッドの一例としてインクジェット式記録装置に利用されるインクジェット式記録ヘッドを挙げて説明したが、本発明の製造方法によって得られた圧電材料は、インク以外の液体を噴射する液体噴射ヘッドにも勿論適用することができる。このような液体噴射ヘッドとしては、例えば、プリンター等の画像記録装置に用いられる各種の記録ヘッド、液晶ディスプレイ等のカラーフィルターの製造に用いられる色材噴射ヘッド、有機ＥＬディスプレイ、ＦＥＤ（電界放出ディスプレイ）等の電極形成に用いられる電極材料噴射ヘッド、バイオｃｈｉｐ製造に用いられる生体有機物噴射ヘッド等が挙げられる。 In the above-described embodiment, the ink jet recording head used in the ink jet recording apparatus has been described as an example of the liquid ejecting head. However, the piezoelectric material obtained by the manufacturing method of the present invention is a liquid other than ink. Needless to say, the present invention can also be applied to a liquid ejecting head that ejects water. Examples of such liquid ejecting heads include various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in manufacturing color filters such as liquid crystal displays, organic EL displays, and FED (field emission displays). ) And the like, electrode material ejection heads used for electrode formation, bio-organic matter ejection heads used for biochip production, and the like.
　本発明の圧電素子は、上述したように、インクジェット式記録ヘッドに代表される液体噴射ヘッドの圧電素子に適用することができるものであるが、これに限定されるものではない。本発明の圧電材料は、液体噴射ヘッド以外の圧電素子応用デバイスに利用される圧電素子にも、適用することが可能である。このような圧電素子応用デバイスとしては、超音波センサー、圧電モーター、超音波モーター、圧電トランス、振動式ダスト除去装置、圧力－電気変換機、超音波発信機、圧力センサー、加速度センサーなどが挙げられる。 As described above, the piezoelectric element of the present invention can be applied to a piezoelectric element of a liquid ejecting head typified by an ink jet recording head, but is not limited thereto. The piezoelectric material of the present invention can also be applied to a piezoelectric element used for a piezoelectric element application device other than a liquid jet head. Examples of such piezoelectric element applied devices include ultrasonic sensors, piezoelectric motors, ultrasonic motors, piezoelectric transformers, vibratory dust removal devices, pressure-electric converters, ultrasonic transmitters, pressure sensors, and acceleration sensors. .
　また、発電装置も挙げられる。発電装置としては、圧力－電気変換効果を使用した発電装置、光による電子励起（光起電力）を使用した発電装置、熱による電子励起（熱起電力）を使用した発電装置、振動を利用した発電装置などがある。 Also, power generation devices can be mentioned. As a power generation device, a power generation device using pressure-electric conversion effect, a power generation device using electron excitation (photoelectromotive force) by light, a power generation device using electron excitation (thermoelectromotive force) by heat, a vibration is used. There are power generation devices.
　また、本発明の圧電材料は、強誘電体メモリーなどの強誘電体素子にも好適に用いることができる。 Also, the piezoelectric material of the present invention can be suitably used for a ferroelectric element such as a ferroelectric memory.
Ｉ　インクジェット式記録ヘッド（液体噴射ヘッド）、　１０　流路形成基板、　１２　圧力発生室、　１３　連通部、　１４　インク供給路、　２０　ノズルプレート、　２１　ノズル開口、　３０　保護基板、　３１　マニホールド部、　３２　圧電素子保持部、　４０　コンプライアンス基板、　５０　弾性膜、　６０　第１電極、　７０　圧電体層、　８０　第２電極、　９０　リード電極、　１００　マニホールド、　１２０　駆動回路、　３００　圧電素子 I Inkjet recording head (liquid jet head), 10 flow path forming substrate, 12 pressure generating chamber, 13 communication section, 14 ink supply path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 manifold section, 32 piezoelectric element Holding part, 40 compliance substrate, 50 elastic film, 60 first electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 manifold, 120 drive circuit, 300 piezoelectric element

Claims (6)

  1. 　単独組成では菱面体晶であり且つキュリー温度がＴｃ１であるペロブスカイト型構造を有する複合酸化物からなる第１成分の非鉛系圧電材料と、単独組成では菱面体晶以外の結晶であり且つキュリー温度がＴｃ２であるペロブスカイト型構造を有する複合酸化物からなる第２成分の非鉛系圧電材料と、からなる２成分系圧電材料の製造方法であって、
    　前記Ｔｃ１と前記Ｔｃ２との差の絶対値｜Ｔｃ１－Ｔｃ２｜が５０℃以下となるように、前記第１成分と第２成分とを選定し、
    　横軸に前記第１成分と前記第２成分との組成比を、縦軸に温度を採った相図において、前記Ｔｃ１と前記Ｔｃ２とを結ぶ直線のうち、第２成分の（第１成分＋第２成分）に対するモル比率が０．１以上０．９以下且つ２８０℃以上に位置する領域の組成を選択して、
    　前記第１成分と前記第２成分とを組み合わせることを特徴とする２成分系圧電材料の製造方法。     A single-component lead-free piezoelectric material made of a complex oxide having a perovskite structure that is rhombohedral in the single composition and has a Curie temperature of Tc1, and a crystal other than the rhombohedral in the single composition and the Curie temperature A second component lead-free piezoelectric material composed of a complex oxide having a perovskite structure with Tc2, and a method for producing a two-component piezoelectric material comprising:
    Selecting the first component and the second component so that the absolute value | Tc1-Tc2 | of the difference between the Tc1 and the Tc2 is 50 ° C. or less;
    In the phase diagram in which the horizontal axis represents the composition ratio of the first component and the second component, and the vertical axis represents temperature, of the straight lines connecting Tc1 and Tc2, the second component (first component + The composition of the region where the molar ratio to the second component) is 0.1 or more and 0.9 or less and 280 ° C. or more is selected,
    A method for producing a two-component piezoelectric material, wherein the first component and the second component are combined.
  2. 　｜Ｔｃ１－Ｔｃ２｜／｜Ｔｃ１＋Ｔｃ２｜≦０．１の関係を満たすように、前記第１成分と前記第２成分とを選定することを特徴とする請求項１に記載の２成分系圧電材料の製造方法。 2. The two-component piezoelectric material according to claim 1, wherein the first component and the second component are selected so as to satisfy a relationship of | Tc 1 −Tc 2 | / | Tc 1 + Tc 2 | ≦ 0.1. Production method.
  3. 　横軸に前記第１成分と前記第２成分との合計に対する前記第２成分のモル比を、縦軸に温度を採った相図において、ＭＰＢ組成を特定し、ＭＰＢ近傍の組成を有するように前記第１成分と前記第２成分とを組み合わせることを特徴とする請求項１又は２に記載の２成分系圧電材料の製造方法。 In the phase diagram in which the horizontal axis represents the molar ratio of the second component to the total of the first component and the second component, and the vertical axis represents temperature, the MPB composition is specified so that the composition has a composition near the MPB. The method for producing a two-component piezoelectric material according to claim 1 or 2, wherein the first component and the second component are combined.
  4. 　前記第１成分は、Ａサイトにバリウムを含むＢａ系、Ｂサイトにニオブを含むＮｂ系、及びＡサイトにビスマスを含むＢｉ系の成分のうち、いずれか１つの成分であり、
    　前記第２成分は、Ａサイトにバリウムを含むＢａ系、Ｂサイトにニオブを含むＮｂ系、及びＡサイトにビスマスを含むＢｉ系の成分のうち、前記第１成分とは異なるいずれか１つの成分である
    ことを特徴とする請求項１～３の何れか一項に記載の２成分系圧電材料の製造方法。     The first component is any one of a Ba-based component containing barium at the A site, a Nb-based component containing niobium at the B site, and a Bi-based component containing bismuth at the A site,
    The second component is any one component different from the first component among Ba-based components containing barium at the A site, Nb-based materials containing niobium at the B site, and Bi-based components containing bismuth at the A site. The method for producing a two-component piezoelectric material according to any one of claims 1 to 3, wherein:
  5. 　請求項１～４の何れか一項の２成分系圧電材料の製造方法で得られた圧電材料からなる圧電体層と、前記圧電体層を挟む電極と、を備えたことを特徴とする圧電素子。 A piezoelectric layer comprising: a piezoelectric layer made of a piezoelectric material obtained by the method for producing a two-component piezoelectric material according to any one of claims 1 to 4; and an electrode sandwiching the piezoelectric layer. element.
  6. 　請求項５に記載の圧電素子を備えた圧電素子応用デバイス。 A piezoelectric element application device comprising the piezoelectric element according to claim 5.
PCT/JP2014/084702 2014-12-26 2014-12-26 Method for producing piezoelectric material, piezoelectric element using piezoelectric material produced using same, and device using piezoelectric element WO2016103515A1 (en)

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