JP2018166188A - Piezoelectric device and piezoelectric device-applied device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a piezoelectric device that includes a piezoelectric layer including a perovskite complex oxide having excellent crystallinity and the (100) preferred orientation; and a piezoelectric element-applied device.SOLUTION: A piezoelectric element includes: a first electrode; a second electrode; and a piezoelectric layer, which is interposed between the first electrode and the second electrode and is a layered structure of a plurality of piezoelectric films containing a crystalline perovskite complex oxide represented by general formula ABO. A first piezoelectric film, formed immediately above the first electrode among the plurality of piezoelectric films contains a perovskite complex oxide comprising potassium, sodium and niobium and having the (100) preferred orientation, where the sodium content is greater than the potassium content in A sites of the perovskite complex oxide.SELECTED DRAWING: Figure 13

Description

  The present invention relates to a piezoelectric element and a piezoelectric element application device.

  In general, a piezoelectric element has a piezoelectric layer having electromechanical conversion characteristics and two electrodes that sandwich the piezoelectric layer. In recent years, development of devices using such piezoelectric elements as drive sources (piezoelectric element applied devices) has been actively conducted. As one of the piezoelectric element application devices, a liquid jet head typified by an ink jet recording head, a MEMS element typified by a piezoelectric MEMS element, an ultrasonic measuring device typified by an ultrasonic sensor, a piezoelectric actuator device, etc. There is.

As a material (piezoelectric material) of a piezoelectric layer of a piezoelectric element, for example, potassium sodium niobate ((K, Na) NbO ₃ , hereinafter referred to as “KNN”) has been proposed. Since KNN exhibits relatively high piezoelectric characteristics, it is considered as a promising candidate for lead-free piezoelectric materials. In a piezoelectric body made of polycrystalline KNN, attempts have been made to improve durability (see, for example, Patent Document 1) and displacement by orienting in a predetermined plane orientation.

In addition, polycrystalline nickel lanthanum (LaNiO ₃ , hereinafter referred to as “LNO”) is used as a buffer layer (also referred to as an orientation control layer), or strontium titanate doped with niobium (Nb) (Nb: SrTiO ₃ ). Attempts have been made to orient KNN, which is a piezoelectric body, in a predetermined plane orientation by using a single crystal substrate (see, for example, Patent Document 2).

JP 2012-124233 A Japanese Patent No. 5716799

However, LNO tends to diffuse into the piezoelectric body during firing at a high temperature, and tends to cause a compositional variation of the piezoelectric body. Further, when the dielectric constant of the buffer layer made of LNO is low, various problems such as difficulty in applying a voltage to the piezoelectric layer may occur. On the other hand, the Nb: SrTiO ₃ single crystal substrate is difficult to put into practical use from the viewpoint of cost.

  Such a problem is not limited to a piezoelectric element mounted on a liquid jet head typified by an ink jet recording head, and similarly exists in piezoelectric elements used in other piezoelectric element application devices.

  The present invention has been made in view of the above circumstances, and has a piezoelectric element having a piezoelectric layer containing a perovskite complex oxide preferentially oriented in the (100) plane and having excellent crystallinity, and application of the piezoelectric element The purpose is to provide a device.

An aspect of the present invention that solves the above problems is a perovskite complex oxide that is sandwiched between a first electrode, a second electrode, and the first electrode and the second electrode, and is represented by the general formula ABO ₃ And a piezoelectric layer that is a laminate of a plurality of piezoelectric films including a crystal of the first piezoelectric body formed on the first electrode of the plurality of piezoelectric films. The film has a perovskite type complex oxide preferentially oriented in the (100) plane and containing potassium, sodium and niobium, and the amount of sodium contained in the A site of the perovskite type complex oxide is larger than the amount of potassium. The piezoelectric element is characterized by the following.
In such an embodiment, a piezoelectric element having a piezoelectric layer containing a perovskite complex oxide that is preferentially oriented in the (100) plane and has excellent crystallinity can be obtained.

Here, in the piezoelectric element, the first piezoelectric film has a composition ratio of potassium (K) and sodium (Na) contained in the A site of the perovskite complex oxide represented by the following formula (1). It is preferable to have a relationship.
0.5 <Na / (Na + K) ≦ 0.9 (1)
According to this, it is possible to obtain a piezoelectric element having a piezoelectric layer that is preferentially oriented in the (100) plane and includes a perovskite complex oxide having excellent crystallinity.

In the piezoelectric element, the first piezoelectric film has a relationship in which the molar ratio (A / B) of the A site to the B site of the perovskite complex oxide is represented by the following formula (2). Is preferred.
0.8 <A / B ≦ 1.4 (2)
According to this, it is possible to obtain a piezoelectric element having a piezoelectric layer that is preferentially oriented in the (100) plane and includes a perovskite complex oxide having excellent crystallinity.

In the piezoelectric element, the first piezoelectric film has a half width of a peak derived from the (100) plane in the perovskite complex oxide crystal measured by an X-ray diffraction method of 0.55 ° or less. Preferably there is.
According to this, a piezoelectric element having a piezoelectric layer including a perovskite complex oxide having excellent displacement characteristics can be obtained.

Another aspect of the present invention is a piezoelectric element application device including any one of the above piezoelectric elements.
According to this aspect, it is possible to provide a piezoelectric element application device that has stable piezoelectric / dielectric characteristics and realizes toughness (mechanical characteristics) against external stress.

1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus. FIG. 2 is an exploded perspective view illustrating a schematic configuration of an ink jet recording head. FIG. 2 is a plan view showing a schematic configuration of an ink jet recording head. FIG. 4 is a cross-sectional view taken along line AA ′ in FIG. 3. The BB 'line expanded sectional view of FIG. Sectional drawing explaining the manufacture example of an ink jet recording head. Sectional drawing explaining the manufacture example of an ink jet recording head. Sectional drawing explaining the manufacture example of an ink jet recording head. Sectional drawing explaining the manufacture example of an ink jet recording head. Sectional drawing explaining the manufacture example of an ink jet recording head. Sectional drawing explaining the manufacture example of an ink jet recording head. Sectional drawing explaining the manufacture example of an ink jet recording head. The graph which shows the relationship of Na ratio of sample 1-9, a half value width, and intensity | strength. The graph which shows the A site ratio, the half value width, and intensity | strength of samples 10-15. The graph which shows the A site ratio, the half value width, and intensity | strength of samples 16-21.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows one embodiment of the present invention and can be arbitrarily changed without departing from the gist of the present invention. In addition, what attached | subjected the same code | symbol in each drawing has shown the same member, and description is abbreviate | omitted suitably. X, Y, and Z represent three spatial axes that are orthogonal to each other. In this specification, the directions along these axes are defined as a first direction X (X direction), a second direction Y (Y direction), and a third direction Z (Z direction), respectively. In the following description, it is assumed that the direction toward the positive (+) direction and the direction opposite to the arrow is the negative (-) direction. The X direction and the Y direction represent in-plane directions of the plate, layer, and film, and the Z direction represents the thickness direction or the stacking direction of the plate, layer, and film.

  In addition, the components shown in each drawing, that is, the shape and size of each part, the thickness of the plate, the layer and the film, the relative positional relationship, the repeating unit, and the like are exaggerated in explaining the present invention. There may be. Furthermore, the term “above” in this specification does not limit that the positional relationship between the components is “just above”. For example, the expressions “first electrode on the substrate” and “piezoelectric layer on the first electrode” may include other configurations between the substrate and the first electrode or between the first electrode and the piezoelectric layer. Do not exclude things that contain elements.

(Embodiment 1)
(Liquid ejecting device)
First, an ink jet recording apparatus which is an example of a liquid ejecting apparatus will be described with reference to the drawings.
FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus. As shown in the drawing, in an ink jet recording apparatus (recording apparatus) I, an ink jet recording head unit (head unit) II is detachably attached to the cartridges 2A and 2B. The cartridges 2A and 2B constitute ink supply means. The head unit II has a plurality of ink jet recording heads (recording heads) 1 (see FIG. 2 and the like) and is mounted on the carriage 3. The carriage 3 is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The head unit II and the carriage 3 are configured such that, for example, a black ink composition and a color ink composition can be ejected, respectively.

  Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), and the carriage 3 on which the head unit II is mounted is moved along the carriage shaft 5. ing. On the other hand, the apparatus main body 4 is provided with a conveyance roller 8 as a conveyance means, and a recording sheet S which is a recording medium such as paper is conveyed by the conveyance roller 8. Note that the conveyance means for conveying the recording sheet S is not limited to the conveyance roller, and may be a belt, a drum, or the like.

  The recording head 1 uses a piezoelectric element 300 (see FIG. 2 etc.) as a piezoelectric actuator device. By using the piezoelectric element 300, it is possible to avoid deterioration of various characteristics (such as durability and ink ejection characteristics) in the recording apparatus I.

(Liquid jet head)
Next, a recording head 1 which is an example of a liquid ejecting head mounted on the liquid ejecting apparatus will be described with reference to the drawings. FIG. 2 is an exploded perspective view showing a schematic configuration of the ink jet recording head. FIG. 3 is a plan view showing a schematic configuration of the ink jet recording head. 4 is a cross-sectional view taken along line AA ′ of FIG. 2 to 4 each show a part of the configuration of the recording head 1, and are omitted as appropriate.

  As shown in the figure, the flow path forming substrate (substrate) 10 is made of, for example, a silicon (Si) single crystal substrate. The material of the substrate 10 is not limited to Si, but may be SOI (Silicon On Insulator), glass, or the like.

  A pressure generation chamber 12 partitioned by a plurality of partition walls 11 is formed on the substrate 10. The pressure generating chambers 12 are juxtaposed along a direction (+ X direction) in which a plurality of nozzle openings 21 that eject ink of the same color are provided side by side.

  In the substrate 10, an ink supply path 13 and a communication path 14 are formed on one end side (+ Y direction side) of the pressure generating chamber 12. The ink supply path 13 is configured so that the area of the opening on the one end portion side of the pressure generating chamber 12 is small. The communication path 14 has substantially the same width as the pressure generation chamber 12 in the + X direction. A communication portion 15 is formed on the outside (+ Y direction side) of the communication path 14. The communication part 15 constitutes a part of the manifold 100. The manifold 100 serves as an ink chamber common to the pressure generation chambers 12. As described above, the substrate 10 is formed with a liquid flow path including the pressure generation chamber 12, the ink supply path 13, the communication path 14, and the communication portion 15.

  On one surface (surface on the −Z direction side) of the substrate 10, for example, a SUS nozzle plate 20 is bonded. Nozzle openings 21 are arranged in the nozzle plate 20 along the + X direction. The nozzle opening 21 communicates with each pressure generation chamber 12. The nozzle plate 20 can be bonded to the substrate 10 with an adhesive, a heat welding film, or the like.

A diaphragm 50 is formed on the other surface (the surface on the + Z direction side) of the substrate 10. The diaphragm 50 is constituted by, for example, an elastic film 51 formed on the substrate 10 and an insulator film 52 formed on the elastic film 51. The elastic film 51 is made of, for example, silicon dioxide (SiO ₂ ), and the insulator film 52 is made of, for example, zirconium oxide (ZrO ₂ ). The elastic film 51 may not be a separate member from the substrate 10. A part of the substrate 10 may be processed to be thin and used as the elastic film 51. The elastic film 51 is not limited to SiO _2, and may be a film using, for example, aluminum oxide (Al ₂ O ₃ ), tantalum oxide (V) (Ta ₂ O ₅ ), silicon nitride (SiN), or the like.

A piezoelectric element 300 including a first electrode 60, a piezoelectric layer 70, and a second electrode 80 is formed on the insulator film 52 with an adhesion layer 56 interposed therebetween. For example, titanium oxide (TiO _x ), titanium (Ti), SiN, or the like is used for the adhesion layer 56 and has a function of improving the adhesion between the piezoelectric layer 70 and the diaphragm 50. Note that the adhesion layer 56 can be omitted.

  In the formation process of the piezoelectric layer 70 to be described later, when an alkali metal such as potassium (K) or sodium (Na) is included in the piezoelectric body constituting the piezoelectric layer 70, it may diffuse into the first electrode 60. is there. Therefore, by providing the insulator film 52 between the first electrode 60 and the substrate 10, the insulator film 52 functions as a stopper, and the arrival of the alkali metal to the substrate 10 can be suppressed.

  The first electrode 60 is provided for each pressure generation chamber 12. That is, the first electrode 60 is configured as an individual electrode independent for each pressure generating chamber 12. The first electrode 60 is formed with a width narrower than the width of the pressure generating chamber 12 in the ± X directions. Further, the first electrode 60 is formed with a width wider than the pressure generation chamber 12 in the ± Y direction. That is, both end portions of the first electrode 60 are formed to the outside of the region facing the pressure generating chamber 12 on the vibration plate 50 in the ± Y direction. A lead electrode 90 is connected to one end of the first electrode 60 (the side opposite to the communication path 14).

  The piezoelectric layer 70 is provided between the first electrode 60 and the second electrode 80. The piezoelectric layer 70 is formed with a width wider than the width of the first electrode 60 in the ± X directions. The piezoelectric layer 70 is formed with a width wider than the length of the pressure generating chamber 12 in the ± Y direction in the ± Y direction. The end of the piezoelectric layer 70 on the ink supply path 13 side (+ Y direction side) is formed to the outside of the + Y direction side end of the first electrode 60. That is, the end of the first electrode 60 on the + Y direction side is covered with the piezoelectric layer 70. On the other hand, the end portion of the piezoelectric layer 70 on the lead electrode 90 side (−Y direction side) is on the inner side (+ Y direction side) than the end portion of the first electrode 60 on the −Y direction side. That is, the end portion on the −Y direction side of the first electrode 60 is not covered with the piezoelectric layer 70. The piezoelectric layer 70 is a thin film piezoelectric body having a predetermined thickness described later.

  The second electrode 80 is continuously provided on the piezoelectric layer 70 and the diaphragm 50 in the + X direction. That is, the second electrode 80 is configured as a common electrode common to the plurality of piezoelectric layers 70. In this embodiment, the 1st electrode 60 comprises the separate electrode provided independently corresponding to the pressure generation chamber 12, and the 2nd electrode 80 is continuously provided over the parallel arrangement direction of the pressure generation chamber 12. FIG. However, the first electrode 60 may constitute a common electrode, and the second electrode 80 may constitute an individual electrode.

  In the present embodiment, the diaphragm 50 and the first electrode 60 are displaced by the displacement of the piezoelectric layer 70 having electromechanical conversion characteristics. That is, the diaphragm 50 and the first electrode 60 substantially function as a diaphragm. However, since the second electrode 80 is also displaced due to the displacement of the piezoelectric layer 70 in practice, the region where the diaphragm 50, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are sequentially laminated is It functions as a movable part (also referred to as a vibration part) of the piezoelectric element 300.

  In the present embodiment, either the elastic film 51 or the insulator film 52 may be omitted to function as a diaphragm, or the elastic film 51 and the insulator film 52 may be omitted and the first electrode 60 may be omitted. Only may function as a diaphragm. When the first electrode 60 is directly provided on the substrate 10, it is preferable to protect the first electrode 60 with an insulating protective film or the like so that ink does not contact the first electrode 60.

  The protective substrate 30 is bonded to the substrate 10 (the vibration plate 50) on which the piezoelectric element 300 is formed by an adhesive 35. The protective substrate 30 has a manifold portion 32. The manifold part 32 constitutes at least a part of the manifold 100. The manifold portion 32 of this embodiment penetrates the protective substrate 30 in the thickness direction (Z direction), and is further formed across the width direction (+ X direction) of the pressure generating chamber 12. The manifold portion 32 communicates with the communication portion 15 of the substrate 10. With these configurations, the manifold 100 serving as an ink chamber common to the pressure generation chambers 12 is configured.

  On the protective substrate 30, a piezoelectric element holding portion 31 is formed in a region including the piezoelectric element 300. The piezoelectric element holding portion 31 has a space that does not hinder the movement of the piezoelectric element 300. This space may or may not be sealed. The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction (Z direction). The end portion of the lead electrode 90 is exposed in the through hole 33.

  Examples of the material of the protective substrate 30 include Si, SOI, glass, ceramics, metal, and resin, but it is more preferable that the protective substrate 30 be formed of a material that is substantially the same as the coefficient of thermal expansion of the substrate 10. In the present embodiment, Si is formed using the same material as the substrate 10.

  A drive circuit 120 that functions as a signal processing unit is fixed on the protective substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC: Integrated Circuit) 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 inserted through the through-hole 33. The drive circuit 120 can be electrically connected to the printer controller 200 (see FIG. 1). Such a drive circuit 120 functions as control means of the piezoelectric actuator device (piezoelectric element 300).

  A compliance substrate 40 including 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 the fixing plate 42 can be made of a hard material such as metal. A region of the fixing plate 42 facing the manifold 100 is an opening 43 that is completely removed in the thickness direction (Z direction). One surface (the surface on the + Z direction side) of the manifold 100 is sealed only with a flexible sealing film 41.

  Such a recording head 1 ejects ink droplets by the following operation. First, 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. Thereafter, according to the recording signal from the drive circuit 120, a voltage is applied between the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, and the piezoelectric element 300 is bent and deformed. As a result, the pressure in each pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle openings 21.

(Piezoelectric actuator device)
Next, the configuration of the piezoelectric element 300 used as the piezoelectric actuator device of the recording head 1 will be described with reference to the drawings.
FIG. 5 is an enlarged sectional view taken along line BB ′ of FIG. As shown in the figure, in the piezoelectric element 300, a diaphragm 50 composed of an elastic film 51 and an insulator film 52 is formed on a substrate 10 on which a pressure generation chamber 12 partitioned by a plurality of partition walls 11 is formed. In addition, the adhesion layer 56, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are sequentially laminated, and a movable part is formed by these layers.

The piezoelectric layer 70 is a laminated body composed of a plurality of piezoelectric films 74 (see FIG. 8), and the piezoelectric material constituting the piezoelectric layer 70 is a perovskite structure (ABO ₃ type) represented by a general formula ABO _3. A composite oxide having a perovskite structure) (perovskite-type composite oxide). Of the plurality of piezoelectric films 74, the first piezoelectric film 74a formed immediately above the first electrode 60 is preferentially oriented in the (100) plane. It also contains perovskite type complex oxide crystals containing potassium (K), sodium (Na) and niobium (Nb), and the amount of Na contained in the A site of the ABO ₃ type perovskite structure is larger than the amount of K. It is formed to become.

The KNN-based composite oxide constituting the first piezoelectric film 74a is formed so that the amount of Na contained in the A site of the ABO ₃ type perovskite structure is larger than the amount of K. Specifically, it is preferable that the composition ratio of K and Na contained in the A site has a relationship represented by the following formula (3). In the following formula (3), X satisfies 0.5 <X ≦ 0.9.
(K _X , Na _1-X ) NbO ₃ (3)
In the above formula (3), it is preferable that the composition ratio of K and Na contained in the A site of the KNN composite oxide has a relationship represented by the following formula (1).
0.5 <Na / (Na + K) ≦ 0.9 (1)

  That is, the Na content is more than 50 mol% and 90 mol% or less with respect to the total amount of metal elements constituting the A site (in other words, the K content is equal to the total amount of metal elements constituting the A site. It is preferably 10 mol% or more and less than 50 mol%). According to this, a KNN-based composite oxide that is preferentially oriented in the (100) plane and has excellent crystallinity can be obtained, and the piezoelectric layer 70 including the composite oxide having a composition advantageous in piezoelectric characteristics can be obtained.

  The piezoelectric material constituting the first piezoelectric film 74a may be a KNN composite oxide, and is not limited to the composition represented by the above formula (3). For example, other metal elements (additives) may be contained in the A site and B site of potassium sodium niobate. Examples of such additives include manganese (Mn), lithium (Li), barium (Ba), calcium (Ca), strontium (Sr), zirconium (Zr), titanium (Ti), bismuth (Bi), Examples include tantalum (Ta), antimony (Sb), iron (Fe), cobalt (Co), silver (Ag), magnesium (Mg), zinc (Zn), and copper (Cu).

One or more additives of this type may be included. In general, the amount of the additive is 20% or less, preferably 15% or less, more preferably 10% or less, based on the total amount of elements as the main component. The use of additives makes it easy to diversify the structure and functions by improving various characteristics. However, the presence of more than 80% of KNN is preferable from the viewpoint of exhibiting characteristics derived from KNN. Even when a composite oxide containing these other elements, is preferably configured to have a ABO ₃ type perovskite structure.

The alkali metals (K and Na) at the A site in the first piezoelectric film 74a may be added in excess relative to the stoichiometric composition. Further, the alkali metal at the A site may be deficient with respect to the stoichiometric composition. Therefore, the KNN composite oxide contained in the first piezoelectric film 74a can also be expressed by the following formula (4). In the following formula (4), X satisfies 0.5 <X ≦ 0.9.
(K _αX , Na _{α (1-X)} ) NbO ₃ (4)

  In the above formula (4), α represents the amount of K and Na that may be added excessively or the amount of K and Na that may be insufficient. When the amount of K and Na is excessive, 1.0 <α. When the amount of K and Na is insufficient, α <1.0. For example, α = 1.1 represents that 110 mol% of K and Na are contained when the amount of K and Na in the stoichiometric composition is 100 mol%. If α = 0.9, it means that 90 mol% of K and Na are contained when the amount of K and Na in the stoichiometric composition is 100 mol%. If the alkali metal at the A site is neither excessive nor insufficient with respect to the stoichiometric composition, α = 1. From the viewpoint of orientation and crystallinity, 0.8 <α ≦ 1.4 is preferable.

In other words, in the formula (4), the molar ratio (A / B) of the A site (K + Na) to the B site (Nb) of the KNN composite oxide has a relationship represented by the following formula (2). Is preferred.
0.8 <A / B ≦ 1.4 (2)

  Piezoelectric materials include materials having a composition in which some of the elements are deficient, materials having a composition in which some of the elements are excessive, and materials having a composition in which some of the elements are replaced with other elements. . As long as the basic characteristics of the piezoelectric layer 70 do not change, materials that deviate from the stoichiometric composition due to defects or excess, or materials in which some of the elements are replaced with other elements are also applicable to the piezoelectric according to the present embodiment. Included in the material.

As used herein, "K, composite oxides of ABO ₃ type perovskite structure containing Na and Nb," A, K, is not limited only to the composite oxide ABO ₃ type perovskite structure containing Na and Nb. That is, this composite oxide includes an ABO ₃ type perovskite structure oxide containing K, Na, and Nb (for example, the KNN type composite oxide exemplified above) and another composite oxide having an ABO ₃ type perovskite structure. And a piezoelectric material expressed as a mixed crystal containing a material.

  Other composite oxides are not particularly limited, but are preferably lead-free piezoelectric materials that do not contain Pb from the viewpoint of reducing the environmental load. For example, bismuth ferrate containing bismuth (Bi) and iron (Fe) ( BFO) based composite oxide, Bi, barium (Ba), Fe and Ti containing bismuth ferrate-barium titanate (BF-BT) based composite oxide, Bi, Fe, Mn, Ba and Ti containing iron Perovskite complex oxides such as bismuth manganate-barium titanate (BFM-BT) complex oxides can be used. The other complex oxide may be a lead-free piezoelectric material that does not contain Pb and Bi depending on the application. According to these, the piezoelectric element 300 is excellent in biocompatibility and has little environmental load.

Other composite oxides include lead zirconate titanate (PZT) containing Pb, zirconium (Zr) and Ti, and metal oxides such as niobium oxide, nickel oxide and magnesium oxide added to this PZT. Lead titanate (PbTiO ₃ ), lead zirconate (PbZrO ₃ ), lead lanthanum titanate ((Pb, La), TiO ₃ ), lead lanthanum zirconate titanate ((Pb, La)) (Zr, Ti) O ₃ ), lead magnesium niobate, zirconium titanate (Pb (Zr, Ti) (Mg, Nb) O ₃ ), or the like can be used.

  The first piezoelectric film 74a constituting the piezoelectric layer 70 includes the above-described KNN composite oxide. Specifically, the first piezoelectric film 74a is heat-treated by removing unnecessary substances such as a solvent from the KNN crystal (KNN-based complex oxide precursor solution) preferentially oriented on the (100) crystal plane by crystallization. It is a KNN film that is crystallized by the following method.

  In the present specification, the preferential orientation means that 50% or more, preferably 80% or more of the crystals are oriented in a predetermined crystal plane. For example, “preferentially oriented in the (100) plane” means that all the crystals of the piezoelectric layer 70 are oriented in the (100) plane and more than half of the crystals (50% or more, preferably 80%). Includes the case of being oriented in the (100) plane.

  The first piezoelectric film 74a in which the KNN crystal is preferentially oriented with respect to the (100) plane is a half of the peak derived from the (100) plane in the perovskite complex oxide crystal measured by X-ray diffraction. The value width is 0.55 ° or less. According to this, the piezoelectric element 300 having the piezoelectric layer 70 containing the perovskite complex oxide having excellent displacement characteristics can be obtained.

  In general, when controlling the crystal orientation of a piezoelectric material constituting a piezoelectric layer, the orientation control layer (also referred to as a buffer layer) is provided between the first electrode and the piezoelectric layer, for example, on the adhesion layer. Is preferably provided. By providing the orientation control layer, the piezoelectric body constituting the piezoelectric layer can be preferentially oriented in a predetermined plane orientation, for example, (100) plane.

  On the other hand, when a KNN film in which the KNN crystal is not preferentially oriented with respect to the (100) plane is used as a buffer layer, or depending on the manufacturing method of the KNN film, the random orientation or other such as (110) plane or (111) plane In some cases, the orientation is preferentially oriented in the plane orientation.

  However, in this embodiment, the amount of Na and the amount of K contained in the A site of the KNN-based composite oxide contained in the first piezoelectric film 74a among the plurality of piezoelectric films 74 constituting the piezoelectric layer 70 are set as above. By prescribing as in formula (1), a KNN-based composite oxide that is preferentially oriented in the (100) plane and excellent in crystallinity (good orientation) has a composition advantageous for piezoelectric characteristics. Thus, the piezoelectric layer 70 including the complex oxide can be obtained. That is, as long as the amount of Na and the amount of K contained in the A site of the KNN composite oxide are defined as in the above formula (1), the buffer layer is formed when the piezoelectric layer 70 is formed from the KNN composite oxide. It does not have to be provided.

  Further, a KNN composite oxide is used as the piezoelectric material constituting the first piezoelectric film 74a, and a perovskite composite other than the KNN composite oxide is used as the piezoelectric material constituting the plurality of piezoelectric films 74 formed on the upper layer. An oxide can also be used. The perovskite complex oxide other than the KNN complex oxide may be the above-mentioned lead-free piezoelectric material or lead-based piezoelectric material. In this case, the first piezoelectric film 74a using the KNN-based complex oxide in which the Na amount and the K amount contained in the A site are defined as in the above formula (1) functions as a buffer layer. As a result, a plurality of piezoelectric films 74 containing a perovskite complex oxide excellent in crystal orientation and regularity can be formed.

Further, by using the first piezoelectric film 74a in which the amount of Na and the amount of K are defined as in the above formula (1) as the orientation control layer, for example, preferential orientation is easily performed on the (110) plane or the (111) plane. Even if a plurality of piezoelectric films 74 including a piezoelectric material are formed to obtain the piezoelectric layer 70, the crystal plane orientation is easily preferentially oriented in the (100) direction. For example, by using the first piezoelectric film 74a as an orientation control layer, potassium niobate (KNbO ₃ ), titanic acid, which is difficult to be preferentially oriented to the (100) crystal plane without the orientation control layer, is used. Bismuth sodium ((Bi _0.5 , Na _0.5 ) TiO ₃ ), bismuth ferrate (BiFeO ₃ ) and the like can be oriented.
The piezoelectric layer 70 excellent in crystal orientation and crystallinity has an advantage that various characteristics can be easily improved as compared with the piezoelectric layer preferentially oriented in the random orientation or other crystal planes.

  In the piezoelectric element 300, the elastic film 51 has a thickness of 0.1 μm or more and 2.0 μm or less, the insulator film 52 has a thickness of 0.01 μm or more and 1.0 μm or less, and the adhesion layer 56 has a thickness of 0.005 μm. The thickness of the first electrode 60 is 0.01 μm or more and 1.0 μm or less, the thickness of the piezoelectric layer 70 is 0.1 μm or more and 3.0 μm or less, and the thickness of the second electrode 80 is 0.1 μm or less. Is preferably 0.01 μm or more and 1.0 μm or less. Note that when the first piezoelectric film 74a is formed as the buffer layer, the thickness of the buffer layer is set to 0.20 μm or less, preferably 0.01 μm to 0.10 μm. Note that the thicknesses of the elements listed here are merely examples, and can be changed without departing from the scope of the present invention.

The material of the first electrode 60 and the second electrode 80 may be any electrode material that does not oxidize when forming the piezoelectric element 300 and can maintain conductivity. Examples of such materials include metal materials such as platinum (Pt), iridium (Ir), gold (Au), aluminum (Al), copper (Cu), Ti, silver (Ag), and stainless steel; iridium oxide (IrO _X ), indium tin oxide (ITO), tin oxide-based conductive materials such as fluorine-doped tin oxide (FTO), zinc oxide-based conductive materials such as gallium-doped zinc oxide (GZO), strontium ruthenate (SrRuO ₃ ), Examples thereof include oxide conductive materials such as lanthanum nickelate (LaNiO ₃ ) and element-doped strontium titanate; conductive polymers and the like. As the electrode material, any of the above materials may be used alone, or a laminate in which a plurality of materials are laminated may be used. The electrode material of the first electrode 60 and the electrode material of the second electrode 80 may be the same or different.

(Piezoelectric element manufacturing method)
Next, an example of a method for manufacturing the piezoelectric element 300 will be described with reference to the drawings together with the method for manufacturing the recording head 1. 6 to 12 are cross-sectional views illustrating an example of manufacturing an ink jet recording head.

First, as shown in FIG. 6, a Si single crystal substrate is prepared as the substrate 10. Next, the substrate 10 is thermally oxidized to form an elastic film 51 made of SiO _{2 on the} surface thereof. Further, a zirconium film is formed on the elastic film 51 by a sputtering method, a vapor deposition method or the like, and is thermally oxidized to obtain an insulator film 52 made of ZrO ₂ . In this way, the diaphragm 50 composed of the elastic film 51 and the insulator film 52 is formed on the substrate 10. Next, an adhesion layer 56 made of TiO _X is formed on the insulator film 52. The adhesion layer 56 can be formed by sputtering or thermal oxidation of a Ti film. Next, the first electrode 60 made of Pt is formed on the adhesion layer 56. The first electrode 60 can be appropriately selected according to the electrode material. For example, vapor phase film formation such as sputtering, vacuum deposition (PVD), laser ablation, liquid phase film formation such as spin coating, etc. Can be formed.

  Next, as shown in FIG. 7, a resist having a predetermined shape (not shown) is formed on the first electrode 60 as a mask, and the adhesion layer 56 and the first electrode 60 are patterned simultaneously. The patterning of the adhesion layer 56 and the first electrode 60 can be performed, for example, by dry etching such as reactive ion etching (RIE) or ion milling, or wet etching using an etching solution. In addition, the shape in the patterning of the adhesion layer 56 and the first electrode 60 is not particularly limited.

  Next, as shown in FIG. 8, a first piezoelectric film 74a is formed on the first electrode 60, and a plurality of piezoelectric films 74 are formed thereon. The piezoelectric layer 70 includes a first piezoelectric film 74a and a plurality of piezoelectric films 74. The piezoelectric layer 70 can be formed by, for example, a chemical solution method (wet method) that obtains a metal oxide by applying and drying a solution containing a metal complex (precursor solution) and baking at a high temperature. In addition, it can also be formed by a laser ablation method, a sputtering method, a pulse laser deposition method (PLD method), a CVD (Chemical Vapor Deposition) method, an aerosol deposition method, or the like. In this embodiment, the wet method (liquid phase method) was used from the viewpoint of aligning the plane orientation of the piezoelectric layer 70 in the (100) direction.

  Here, the wet method (liquid phase method) is a method of forming a film by a chemical solution method such as a MOD method or a sol-gel method, and is a concept distinguished from a vapor phase method such as a sputtering method. In the present embodiment, a vapor phase method may be used as long as the piezoelectric layer 70 whose plane orientation is oriented in the (100) direction can be formed.

  For example, the piezoelectric layer 70 formed by a wet method (liquid phase method), which will be described in detail later, is a step of applying a precursor solution to form a precursor film (application step), and drying the precursor film. The first step formed by a series of steps from a step (drying step), a step of heating and degreasing the dried precursor film (degreasing step), and a step of firing the degreased precursor film (firing step). A piezoelectric film 74a and a plurality of piezoelectric films 74 are provided. That is, the piezoelectric layer 70 is formed by repeating a series of steps from the coating step to the firing step a plurality of times. In the series of steps described above, the firing step may be performed after the application step to the degreasing step are repeated a plurality of times.

  A layer or film formed by a wet method has an interface. A layer or film formed by a wet method has a trace of coating or baking, and such a trace observes the cross section or analyzes the concentration distribution of elements in the layer (or in the film). This is an interface that can be confirmed. Strictly speaking, the interface means a boundary between layers or films, but here, it means a vicinity of the boundary between layers or films. When a cross section of a layer or film formed by a wet method is observed with an electron microscope or the like, such an interface is near the boundary with an adjacent layer or film, or is darker than others, or more colored than others. Is confirmed as a thin part. In addition, when analyzing the concentration distribution of elements, such an interface is confirmed as a portion where the element concentration is higher than the other, or a portion where the element concentration is lower than the other, in the vicinity of the boundary with the adjacent layer or film. Is done. The piezoelectric layer 70 is formed by repeating a series of steps from the coating step to the firing step, or by repeating the firing step after repeating the steps from the coating step to the degreasing step (first piezoelectric body). Therefore, it has a plurality of interfaces corresponding to the first piezoelectric film 74a and each piezoelectric film 74.

  An example of a specific procedure when the piezoelectric layer 70 is formed by a wet method is as follows. First, a precursor solution for forming the piezoelectric layer 70 made of a MOD solution or sol containing a metal complex is adjusted (adjustment step). Then, the precursor solution of the piezoelectric layer 70 is applied onto the patterned first electrode 60 using a spin coating method or the like to form a precursor film (application process). Next, the precursor film is heated to a predetermined temperature, for example, 130 ° C. to 250 ° C., and dried for a predetermined time (drying process), and the dried precursor film is further heated to a predetermined temperature, for example, 300 ° C. to 450 ° C. Degreasing by holding for a certain time (degreasing step). Further, the degreased precursor film is heated to a higher temperature, for example, from 500 ° C. to 800 ° C., and kept at this temperature for a certain period of time to crystallize to form the first piezoelectric film 74a (firing step). After the formation of the first piezoelectric film 74a, the coating process, the drying process, the degreasing process, and the baking process are repeated a plurality of times, thereby forming the first piezoelectric film 74a and a plurality of piezoelectric films 74. The piezoelectric layer 70 is formed.

  In addition, each above-mentioned precursor solution melt | dissolves or disperse | distributes the metal complex which can form a perovskite type complex oxide to an organic solvent by baking, respectively. That is, the precursor solution of the piezoelectric layer 70 contains a predetermined element (K, Na and Nb in the first piezoelectric film 74a) as the central metal of the metal complex. At this time, a metal complex containing an element other than the predetermined element may be further mixed in the precursor solution of the piezoelectric layer 70.

  As the metal complex containing the predetermined element, for example, alkoxide, organic acid salt, β-diketone complex and the like can be used. In each of the precursor solutions described above, the mixing ratio of these metal complexes may be mixed so that the predetermined element contained in the perovskite complex oxide has a desired molar ratio.

  For example, in the KNN composite oxide included in the first piezoelectric film 74a, examples of the metal complex containing K include potassium 2-ethylhexanoate and potassium acetate. Examples of the metal complex containing Na include sodium 2-ethylhexanoate and sodium acetate. Examples of the metal complex containing Nb include niobium 2-ethylhexanoate and pentaethoxyniobium. When Mn is added as an additive, examples of the metal complex containing Mn include manganese 2-ethylhexanoate. At this time, two or more metal complexes may be used in combination. For example, potassium 2-ethylhexanoate and potassium acetate may be used in combination as a metal complex containing K.

  Examples of the organic solvent used for preparing the precursor solution include propanol, butanol, pentanol, hexanol, octanol, ethylene glycol, propylene glycol, octane, decane, cyclohexane, xylene, toluene, tetrahydrofuran, acetic acid, octylic acid, 2 -N-butoxyethanol, n-octane, etc., or these mixed solvents are mentioned.

The precursor solution may include an additive that stabilizes the dispersion of each metal complex. Examples of such additives include 2-ethylhexanoic acid and diethanolamine.
Examples of the heating device used in the drying step, the degreasing step, and the firing step include an RTA (Rapid Thermal Annealing) device that heats by irradiation with an infrared lamp, a hot plate, and the like.

  Next, as shown in FIG. 9, the piezoelectric layer 70 is patterned. Patterning can be performed by dry etching such as reactive ion etching or ion milling, or wet etching using an etchant. In addition, the shape in patterning of the piezoelectric layer 70 is not particularly limited. Thereafter, the second electrode 80 is formed on the patterned piezoelectric layer 70. The second electrode 80 can be formed by the same method as the first electrode 60.

  In addition, before and after forming the second electrode 80 on the piezoelectric layer 70, reheating treatment (post-annealing) may be performed in a temperature range of 600 ° C. to 800 ° C. as necessary. As described above, by performing post-annealing, good interfaces between the adhesion layer 56 and the first electrode 60, the first electrode 60 and the piezoelectric layer 70, and the piezoelectric layer 70 and the second electrode 80 are formed, respectively. And the crystallinity of the piezoelectric layer 70 can be improved.

In the present embodiment, an alkali metal (K or Na) is included in the piezoelectric material of the first piezoelectric film 74a. Alkali metal easily diffuses into the first electrode 60 in the above-described firing step. If the alkali metal passes through the first electrode 60 and reaches the substrate 10, it reacts with the substrate 10. However, in this embodiment, the insulator film 52 made of ZrO ₂ serves as a stopper function for K and Na. Therefore, it can suppress that an alkali metal reaches the substrate 10 which is a Si substrate.

Next, although not shown, the lead electrode 90 is formed and patterned into a predetermined shape (see FIG. 4).
Next, as shown in FIG. 10, a protective substrate wafer (not shown), which is a silicon wafer and serves as a plurality of protective substrates 30, is attached to the piezoelectric element 300 side of a flow path forming substrate wafer (not shown) with an adhesive 35 (FIG. 4). Then, the flow path forming substrate wafer is thinned to a predetermined thickness.

  Next, as shown in FIG. 11, a mask film 53 is newly formed on the flow path forming substrate wafer and patterned into a predetermined shape. Then, as shown in FIG. 12, the pressure corresponding to the piezoelectric element 300 is obtained by performing anisotropic etching (wet etching) using an alkali solution such as KOH on the flow path forming substrate wafer through the mask film 53. A generation chamber 12, an ink supply path 13, a communication path 14, a communication portion 15, and the like (see FIG. 4) are formed.

  Thereafter, unnecessary portions on 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, the nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate wafer opposite to the protective substrate wafer is bonded, and the compliance substrate 40 is bonded to the protective substrate wafer. The ink jet recording head (recording head 1) of the present embodiment is obtained by dividing the wafer for forming substrate or the like into a single chip size substrate 10 as shown in FIG.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to a following example.
(Production of sample 1)
First, a 6-inch (100) -plane Si single crystal substrate (substrate 10) was thermally oxidized to form an SiO ₂ film (elastic film 51) on the surface of the substrate 10. A Zr film is formed on the elastic film 51 by a sputtering method, and the Zr film is thermally oxidized to form a ZrO ₂ film (insulator film 52), and the diaphragm 50 including the elastic film 51 and the insulator film 52 is formed. Formed. Next, a Ti layer was formed on the insulator film 52 by a sputtering method, and the Ti layer was thermally oxidized to form a TiO _X layer (adhesion layer 56). Next, a Pt electrode film was formed on the adhesion layer 56 by sputtering at 450 ° C. Next, a predetermined photoresist pattern was formed on the Pt electrode film, and the Pt electrode film and the adhesion layer 56 were patterned into a predetermined shape by ion milling to form a Pt electrode (first electrode 60).

Next, a precursor solution composed of potassium 2-ethylhexanoate, sodium 2-ethylhexanoate and niobium 2-ethylhexanoate was prepared. By using this precursor solution, a KNN layer (piezoelectric layer 70) made of a KNN-based composite oxide, which will be described later, has a composition ratio of K and Na of the first KNN film (first piezoelectric film 74a). And the composition ratio of K and Na of the second-layer KNN film (piezoelectric film 74) is the composition as shown in Sample 1 of Table 1 below (K _0.8 , Na _0.2 ) NbO ₃ and the A site ratio (A / B) was 1.

  Next, the prepared precursor solution was applied by spin coating at 1500 rpm to 3000 rpm on the substrate 10 (hereinafter simply referred to as “substrate 10”) on which the first electrode 60 was formed (application step). Next, the substrate 10 was placed on a hot plate and dried at 180 ° C. (drying process). Subsequently, degreasing was performed on the hot plate at 380 ° C. on the hot plate (degreasing step). Subsequently, the heat treatment for 3 minutes was performed at 600 degreeC using the RTA apparatus (baking process). Then, the first piezoelectric film 74a was formed.

  Next, a single piezoelectric film 74 is formed by performing such a process from the coating process to the firing process once, and a KNN layer (piezoelectric layer) having a thickness of 160 nm constituted by a total of two piezoelectric films. 70) was formed and this was designated as Sample 1.

(Manufacture of samples 2-9)
The piezoelectric layer 70 was formed in the same manner as in the sample 1 except that the precursor solution was adjusted so that the composition of the KNN-based composite oxide constituting the piezoelectric layer 70 was as shown in Table 1 below. Samples 2 to 9 were used respectively. In Sample 8, the piezoelectric layer 70 is composed of an NN layer made of NaNbO ₃ (NN), and in Sample 9, the piezoelectric layer 70 is composed of a KN layer made of KNbO ₃ (KN).

(Manufacture of samples 10-15)
Samples 10 to 15 in which the Na ratio of sample 5 (Na / (Na + K) = 0.6) having the highest strength was fixed and the A site ratio (A / B) was changed were produced. In Samples 10 to 15, A> 1 when the amount of K and Na is excessive, and A <1 when the amount of K and Na is insufficient. The piezoelectric layer 70 was formed in the same manner as in the sample 1 except that the precursor solution was adjusted so that the composition of the KNN-based composite oxide constituting the piezoelectric layer 70 was as shown in Table 2 below. Samples 10 to 15 were used respectively.

(Manufacture of samples 16 to 21)
Samples 16 to 21 were prepared by fixing the Na ratio of Sample 6 (Na / (Na + K) = 0.8) and changing the A site ratio (A / B). The piezoelectric layer 70 was formed in the same manner as in the sample 1 except that the precursor solution was adjusted so that the composition of the KNN-based composite oxide constituting the piezoelectric layer 70 was as shown in Table 3 below. Samples 16 to 21 were used.

(Manufacture of sample 22)
The KNN composite oxide constituting the piezoelectric layer 70 is composed of the composition ratio of K, Na, and Mn of the first piezoelectric film 74a and the composition ratio of K, Na, and Mn of the second piezoelectric film 74. Except that the precursor solution was adjusted so as to be (K _0.4 , Na _0.6 ) (Nb _0.995 Mn _0.005 ) O ₃ having the composition as shown in Table 4 below. A piezoelectric layer 70 was formed in the same manner as in Example 1, and Sample 22 was obtained.

(Manufacture of sample 23)
The composition ratio of K and Na of the first piezoelectric film 74a in the KNN-based composite oxide constituting the piezoelectric layer 70 is the composition shown in Table 4 below (K _0.4 , Na _0.6 ). A piezoelectric solution was prepared in the same manner as in Sample 1 except that the precursor solution was adjusted to be NbO ₃ and a precursor solution for NaNbO ₃ (NN) was prepared to form the second piezoelectric film 74. A body layer 70 was formed and used as sample 23.

(Manufacture of sample 24)
The composition ratio of K and Na of the first piezoelectric film 74a in the KNN-based composite oxide constituting the piezoelectric layer 70 is the composition shown in Table 4 below (K _0.4 , Na _0.6 ). The precursor solution is adjusted to be NbO _3, and a precursor solution for (Bi _0.5 , Na _0.5 ) TiO ₃ (BNT) is prepared to form the second piezoelectric film 74. Except for this, the piezoelectric layer 70 was formed in the same manner as in the sample 1, and the sample 24 was obtained.

(Manufacture of sample 25)
The composition ratio of K and Na of the first piezoelectric film 74a in the KNN-based composite oxide constituting the piezoelectric layer 70 is the composition shown in Table 4 below (K _0.4 , Na _0.6 ). A piezoelectric solution was prepared in the same manner as Sample 1 except that the precursor solution was adjusted to be NbO _3, and a precursor solution for BiFeO ₃ (BF) was prepared to form the second piezoelectric film 74. A body layer 70 was formed and used as Sample 25.

(XRD measurement)
For samples 1 to 25, measurement of the X-ray diffraction pattern of the piezoelectric layer 70 was performed at room temperature by using an X-ray diffraction (XRD) method using “D8 Discover” manufactured by Bruker AXS Co., Ltd. I went there. In this measurement, the source was CuKα, the X-ray collimator was 0.1 mmφ, and the detector was a two-dimensional detector (GAADDS). The tube voltage and tube current at the time of measurement were 50 kV and 100 mA, respectively. The measurement conditions were set to 10 for ω, 35 for 2θ, and 120 seconds for the integration time. The two-dimensional measurement results obtained here are used as a one-dimensional diffraction pattern in the integration range 2θ = 20 to 50 and χ = −95 to −85, and the diffraction intensity (peak intensity) (Counts) and half width (°) are calculated. did.

  In general, in the X-ray diffraction pattern of the KNN layer (piezoelectric layer 70), a peak derived from the (100) plane is observed when 2θ is near 22.5 °, and a peak derived from the (110) plane is observed near 32.0 °. Is done. In Samples 1-7, Samples 11-15, and Samples 17-25, a peak was observed when 2θ was around 22.5 °, and no peak was observed around 32.0 °. Thereby, it was found that the piezoelectric layers 70 of Samples 1 to 7, Samples 11 to 15, and Samples 17 to 25 were preferentially oriented in the (100) plane. Moreover, the intensity | strength (Counts) and half value width (degree) of the peak originating in the (100) plane of each sample were computed, and these were shown to Tables 1-4. In Samples 8 to 10 and Sample 16, since no peak derived from the (100) plane was observed, the intensity became 0 and the half-value width could not be calculated.

  Moreover, based on Tables 1-3, the relationship of the composition ratio in each sample, a half value width, and peak intensity was graphed. FIG. 13 is a graph showing the relationship between Na ratio, half width and strength of Samples 1-9, and FIG. 14 is a graph showing the relationship between A site ratio, half width and strength of Samples 10-15. 15 is a graph showing the relationship between the A-site ratio, the half-value width, and the strength of samples 16 to 21.

  As shown in Tables 1 to 4 and FIGS. 13 to 15, the composition ratio of potassium and sodium contained in the A site of the KNN composite oxide constituting the first piezoelectric film 74 a is 0.5 <Na / (Na + K). ) ≦ 0.9, the samples 4 to 7 were confirmed to have a large peak intensity (Counts) derived from the (100) plane and a half width (°) of 0.55 ° or less. It was. That is, by adjusting the composition ratio of potassium and sodium of the KNN composite oxide constituting the piezoelectric layer 70 and the molar ratio of the A site to the B site (A / B) within a predetermined range, the KNN composite oxidation is performed. It has been clarified that the piezoelectric layer 70 can be obtained by preferentially orienting the object in the (100) plane and having excellent crystallinity.

  In addition to the above, Samples 11 to 15 and Samples 17 to 17 in which the molar ratio (A / B) of the A site to the B site of the KNN composite oxide is in the range of 0.8 <A / B ≦ 1.4. 21 and Sample 22 containing 10 mol% or less of Mn as an additive, or Samples 23 to 25 in which the second piezoelectric film 74 is a perovskite complex oxide other than a KNN complex oxide It was confirmed that the composite oxide was excellent in orientation and crystallinity.

  Although not shown in the embodiment, a first piezoelectric film 74a is formed as in samples 4 to 7, samples 11 to 15, and samples 17 to 25, and a plurality of piezoelectric films 74 are formed thereon. Thus, even when the thickness of the piezoelectric layer 70 is set to, for example, 0.1 μm or more and 3.0 μm or less, excellent orientation and crystallinity of various composite oxides can be maintained.

  On the other hand, Samples 1 to 3, Samples 8 to 10, and Sample 16 that do not meet the above conditions are the piezoelectric layer 70 in which the KNN-based composite oxide is not preferentially oriented in the (100) plane, or the regularity (orientation of the crystal) of the crystal. The piezoelectric layer 70 was inferior in the direction).

(Other embodiments)
In the above embodiment, the liquid ejecting head mounted on the liquid ejecting apparatus has been described as an example of the piezoelectric element application device, but the scope of application of the present invention is not limited to this. Further, although an ink jet recording head has been described as an example of the liquid ejecting head, the present invention can of course be applied to a liquid ejecting head that ejects liquid other than ink. Examples of liquid ejecting heads that eject liquids other than ink include color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, and organic EL material ejecting used in the formation of light-emitting layers and charge transport layers of organic EL displays. Head, electrode material ejection head for forming electrode pattern by drawing electrode driver solution, curable material ejection head for three-dimensional arbitrary modeling (3D printing) by repeating material ejection and material curing by light or heat Examples thereof include a piezoelectric material ejecting head that forms an arbitrary piezoelectric element pattern by drawing a piezoelectric material precursor solution and heat treatment, and a bioorganic matter ejecting head used for manufacturing a biochip.

  Since the piezoelectric element and the piezoelectric element application device of the present invention have high piezoelectric characteristics, they can be suitably used for piezoelectric actuators. Specific examples of the piezoelectric actuator device include an ultrasonic transmitter, an ultrasonic motor, a vibration dust removing device, a piezoelectric transformer, a piezoelectric speaker, a piezoelectric pump, a temperature-electric converter, a pressure-electric converter, and the like. .

  Since the piezoelectric element and the piezoelectric element application device of the present invention have high piezoelectric performance, they can be suitably used for piezoelectric sensor elements. Specific sensor elements include, for example, an ultrasonic detector (ultrasonic sensor), an angular velocity sensor (gyro sensor), an acceleration sensor, a vibration sensor, a tilt sensor, a pressure sensor, a collision sensor, a human sensor, an infrared sensor, and terahertz. Sensors, heat detection sensors (heat sensors), pyroelectric sensors, piezoelectric sensors and the like can be mentioned. In addition, the present invention may be applied to filters such as a filter for blocking harmful rays such as infrared rays, an optical filter using a photonic crystal effect due to quantum dot formation, an optical filter using optical interference of a thin film, and the like.

  In an ultrasonic measurement apparatus equipped with an ultrasonic sensor, for example, at least of the piezoelectric element of the present invention, the ultrasonic wave transmitted by the piezoelectric element of the present invention, and the ultrasonic wave received by the piezoelectric element of the present invention. An ultrasonic measurement apparatus can also be configured by including a control unit that measures a detection target using a signal based on one. Such an ultrasonic measurement device is based on the time from when the ultrasonic wave is transmitted to the time when the transmitted ultrasonic wave is reflected back to the measurement object and receives the echo signal. Information on position, shape, speed, and the like is obtained, and a piezoelectric element may be used as an element for generating an ultrasonic wave or an element for detecting an echo signal. As such an ultrasonic wave generation element and an echo signal detection element, an ultrasonic measurement device having excellent displacement characteristics can be provided.

  Since the piezoelectric element and the piezoelectric element application device of the present invention have high ferroelectricity, they can be suitably used for a ferroelectric element. Specific examples of the ferroelectric element include a ferroelectric memory (FeRAM), a ferroelectric transistor (FeFET), a ferroelectric arithmetic circuit (FeLogic), and a ferroelectric capacitor.

  The piezoelectric element and the piezoelectric element application device of the present invention can be suitably used for a voltage-controlled optical element because the domain domain can be controlled by voltage. Specific examples of the optical element include a wavelength converter, an optical waveguide, an optical path modulator, a refractive index control element, and an electronic shutter mechanism.

  Since the piezoelectric element and the piezoelectric element applied device of the present invention exhibit good pyroelectric characteristics, it can be suitably used for a pyroelectric element, and also applied to a robot using the various motors described above as a drive source. can do.

  DESCRIPTION OF SYMBOLS I ... Recording device, II ... Head unit, S ... Recording sheet, 1 ... Recording head, 2A, 2B ... Cartridge, 3 ... Carriage, 4 ... Apparatus main body, 5 ... Carriage shaft, 6 ... Drive motor, 7 ... Timing belt, DESCRIPTION OF SYMBOLS 8 ... Conveyance roller, 10 ... Board | substrate, 11 ... Partition, 12 ... Pressure generation chamber, 13 ... Ink supply path, 14 ... Communication path, 15 ... Communication part, 20 ... Nozzle plate, 21 ... Nozzle opening, 30 ... Protection board, DESCRIPTION OF SYMBOLS 31 ... Piezoelectric element holding part, 32 ... Manifold part, 33 ... Through-hole, 35 ... Adhesive, 40 ... Compliance substrate, 41 ... Sealing film, 42 ... Fixed plate, 43 ... Opening part, 50 ... Vibrating plate, 51 ... Elastic film 52 ... Insulator film 53 ... Mask film 56 ... Adhesion layer 60 ... First electrode 70 ... Piezoelectric layer 74 ... Piezoelectric film 74a ... First piezoelectric film 80 ... Second Electrode, 90 ... lead electrode 100 ... Manifold, 120 ... driving circuit, 121 ... connection wiring, 200 ... printer controller, 300 ... piezoelectric element

Claims (5)

A first electrode;
A second electrode;
A piezoelectric layer that is sandwiched between the first electrode and the second electrode and has a piezoelectric layer that is a laminate of a plurality of piezoelectric films including crystals of a perovskite complex oxide represented by the general formula ABO ₃ An element,
Of the plurality of piezoelectric films, the first piezoelectric film formed immediately above the first electrode is made of a perovskite complex oxide that is preferentially oriented in the (100) plane and contains potassium, sodium, and niobium. A piezoelectric element characterized in that the amount of sodium contained in the A site of the perovskite complex oxide is greater than the amount of potassium. The first piezoelectric film is characterized in that the composition ratio of potassium (K) and sodium (Na) contained in the A site of the perovskite complex oxide is represented by the following formula (1): The piezoelectric element according to claim 1.
0.5 <Na / (Na + K) ≦ 0.9 (1) 2. The first piezoelectric film has a relationship in which a molar ratio (A / B) of an A site to a B site of the perovskite complex oxide is represented by the following formula (2): Or the piezoelectric element of Claim 2.
0.8 <A / B ≦ 1.4 (2)   The half-width of a peak derived from a (100) plane in the crystal of the perovskite complex oxide measured by an X-ray diffraction method is 0.55 ° or less in the first piezoelectric film. The piezoelectric element according to any one of claims 1 to 3.   A piezoelectric element application device comprising the piezoelectric element according to any one of claims 1 to 4.

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