JP6015892B2 - Piezoelectric element, liquid ejecting head, liquid ejecting apparatus, ultrasonic device and sensor - Google Patents

Description

  The present invention relates to a liquid ejecting head, a liquid ejecting apparatus, and a piezoelectric element that include a piezoelectric element having a piezoelectric layer made of a piezoelectric material and an electrode and eject liquid droplets from nozzle openings.

  As a typical example of a liquid ejecting head, for example, a part of a pressure generation chamber communicating with a nozzle for ejecting ink droplets is configured by a vibration plate, and the vibration plate is deformed by a piezoelectric element to add ink in the pressure generation chamber. There is an ink jet recording head that presses and ejects ink droplets from a nozzle. A piezoelectric element used in an ink jet recording head is configured by sandwiching a piezoelectric material (electromagnetic film) made of a piezoelectric material exhibiting an electromechanical conversion function, for example, a crystallized dielectric material, between two electrodes. There is something.

  A piezoelectric material used as a piezoelectric layer constituting such a piezoelectric element is required to have high piezoelectric characteristics (amount of strain), and a typical example is lead zirconate titanate (PZT) (Patent Document 1). reference). However, from the viewpoint of environmental problems, there is a demand for a piezoelectric material with reduced lead or lead content. As a piezoelectric material not containing lead, for example, there is a piezoelectric material containing Bi, Ba, Fe, and Ti (see, for example, Patent Document 2).

JP 2001-223404 A JP 2007-287745 A

  Such a piezoelectric material containing Bi, Ba, Fe, and Ti has a problem that cracks are likely to occur compared to a PZT-based piezoelectric material. In order to solve this problem, the present inventor comprises a composite oxide having a perovskite structure containing at least bismuth, barium, iron and titanium, and the molar ratio of titanium to barium (Ti / Ba) is 1.17 or more and 1.45 or less. Thus, it was found that the generation of cracks can be suppressed. However, such a piezoelectric layer causes a problem that the amount of strain is reduced. Such a problem is not limited to a liquid jet head typified by an ink jet recording head, and similarly exists in other piezoelectric elements.

  In view of such circumstances, an object of the present invention is to provide a liquid ejecting head, a liquid ejecting apparatus, and a piezoelectric element including a piezoelectric element having a piezoelectric layer in which generation of cracks is suppressed and the amount of strain is large.

An aspect of the present invention that solves the above problem is a piezoelectric element that includes a piezoelectric layer and an electrode that sandwiches the piezoelectric layer, and the piezoelectric layer includes bismuth, iron, barium, and titanium and has a perovskite structure. The piezoelectric layer is composed of a first piezoelectric layer, and Ti / Ba, which is provided on the first piezoelectric layer and has a molar ratio of titanium to barium, is higher than that of the first piezoelectric layer. A piezoelectric element having a high second piezoelectric layer.
In such an embodiment, the first piezoelectric layer is composed of a complex oxide having a perovskite structure including bismuth, iron, barium and titanium, and a second piezoelectric layer having a higher Ti / Ba than the first piezoelectric layer. By using the piezoelectric layer, the generation of cracks in the piezoelectric layer can be suppressed, and the amount of strain is relatively large. Moreover, since it does not contain lead or the content of lead can be suppressed, the burden on the environment can be reduced.

  The second piezoelectric layer may have Ti / Ba of 1.45 or less.

According to another aspect of the invention, there is provided a liquid ejecting head including the piezoelectric element, and a liquid ejecting apparatus including the liquid ejecting head. In such an aspect, since the piezoelectric layer in which the generation of cracks is suppressed is provided, the liquid ejecting head and the liquid ejecting apparatus having excellent reliability are obtained. In addition, since the lead is not contained or the lead content is suppressed, the liquid ejecting head and the liquid ejecting apparatus are reduced in environmental load .

Another aspect of the present invention resides in an ultrasonic device including the piezoelectric element, or a sensor including the piezoelectric element. In this aspect, since the piezoelectric element having the piezoelectric layer in which the generation of cracks is suppressed is provided, an ultrasonic device or a sensor with excellent reliability can be realized. Further, since the suppressed content of not containing or lead to lead, ultrasound device burden on the environment is reduced, or may provide a sensor.

FIG. 3 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. FIG. 3 is a plan view of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view and a main part enlarged cross-sectional view of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. The photograph which observed the cross section of the sample 3 by SEM. The figure which shows the X-ray-diffraction pattern of the piezoelectric material layer of the samples 1-4. The figure which shows the X-ray-diffraction pattern of the piezoelectric material layer of the samples 6-9. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment of the present invention.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. ) Is a cross-sectional view taken along the line AA 'of FIG. 2, and FIG. As shown in FIGS. 1 to 3, the flow path forming substrate 10 of the present embodiment is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.

  A plurality of pressure generating chambers 12 are arranged in parallel in the width direction of the flow path forming substrate 10. 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.

  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.

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. On the elastic film 50, for example, titanium oxide having a thickness of about 30 to 50 nm or the like. An adhesion layer 56 for improving adhesion between the first electrode 60 such as the elastic film 50 and the like is provided. In the present embodiment, titanium oxide is used as the adhesion layer 56, but the material of the adhesion layer 56 varies depending on the first electrode 60 and the type of the underlying layer, but for example, an oxide or nitride containing zirconium or aluminum, , SiO ₂ , MgO, CeO ₂ or the like. Note that an insulator film made of zirconium oxide or the like may be provided on the elastic film 50 as necessary.

  Further, on the adhesion layer 56, a first electrode 60, a piezoelectric layer 70 which is a thin film having a thickness of 3 μm or less, preferably 0.3 to 1.5 μm, and a second electrode 80 are laminated. Thus, a piezoelectric element 300 is configured as pressure generating means for causing a pressure change in the pressure generating chamber 12. 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.

  Further, as shown in FIG. 3B, the piezoelectric layer 70 is provided on the first piezoelectric layer 71 provided on the first electrode 60 and the first piezoelectric layer 71 in the present embodiment. And the second piezoelectric layer 72 formed.

The first piezoelectric layer 71 is made of a complex oxide having a perovskite structure including bismuth (Bi), iron (Fe), barium (Ba), and titanium (Ti). In the A site of the perovskite structure, that is, the ABO ₃ type structure, oxygen is 12-coordinated, and the B site is 6-coordinated of oxygen to form an octahedron. Bi and Ba are located at the A site, and Fe and Ti are located at the B site.

  The composite oxide having a perovskite structure including Bi, Fe, Ba and Ti constituting the first piezoelectric layer 71 is a composite oxide having a perovskite structure of a mixed crystal of bismuth ferrate and barium titanate, Alternatively, it is also expressed as a solid solution in which bismuth ferrate and barium titanate are uniformly dissolved. In the X-ray diffraction pattern, bismuth ferrate and barium titanate are not detected alone.

Here, bismuth ferrate and barium titanate are known piezoelectric materials each having a perovskite structure, and those having various compositions are known. For example, as bismuth ferrate and barium titanate, in addition to BiFeO ₃ and BaTiO ₃ , some elements are missing or excessive, or some elements are replaced with other elements. In the present invention, when expressed as bismuth ferrate or barium titanate, as long as the basic characteristics are not changed, those that deviate from the stoichiometric composition due to deficiency or excess, or some of the elements are replaced with other elements. Shall also be included in the ranges of bismuth ferrate and barium titanate.

The composition of the first piezoelectric layer 71 made of a complex oxide having such a perovskite structure is represented, for example, as a mixed crystal represented by the following formula (1). Moreover, this formula (1) can also be expressed by the following formula (1 ′). Here, the description of the formula (1) and the formula (1 ′) is a composition notation based on the stoichiometry, and as described above, as long as the perovskite structure can be taken, an unavoidable composition due to lattice mismatch, oxygen deficiency, etc. Of course, partial substitution of elements and the like are allowed. For example, if the stoichiometric ratio is 1, the range of 0.85 to 1.20 is allowed.
(1-x) [BiFeO ₃ ] -x [BaTiO ₃ ] (1)
(0 <x <0.40)
(Bi _1-x Ba _x ) (Fe _1-x Ti _x ) O ₃ (1 ′)
(0 <x <0.40)

  Further, the complex oxide constituting the first piezoelectric layer 71 may further contain an element other than Bi, Fe, Ba, and Ti. Examples of other elements include Mn and Co. Of course, even a complex oxide containing other elements needs to have a perovskite structure.

  When the first piezoelectric layer 71 contains Mn and Co, it is estimated that Mn and Co are located at the B site, and Mn and Co are complex oxides having a structure in which a part of Fe located at the B site is substituted. Is done. For example, when Mn is included, the composite oxide constituting the first piezoelectric layer 71 has a structure in which a part of Fe in a solid solution in which bismuth ferrate and barium titanate are uniformly dissolved, is substituted with Mn, or It is expressed as a composite oxide having a perovskite structure of mixed crystal of bismuth ferrate manganate and barium titanate, and its basic characteristics are a composite oxide having a perovskite structure of mixed crystal of bismuth ferrate and barium titanate. Although the same, it has been found that the leakage characteristics are improved. Further, when Co is included, the leakage characteristics are improved similarly to Mn. In the X-ray diffraction pattern, bismuth ferrate, barium titanate, bismuth ferrate manganate and bismuth ferrate cobaltate are not detected alone. Further, although Mn and Co have been described as examples, it has been found that leakage characteristics are similarly improved when two other transition metal elements are included at the same time. In addition, other known additives may be included to improve the properties.

The first piezoelectric layer 71 made of a composite oxide having a perovskite structure including Mn and Co in addition to Bi, Fe, Ba, and Ti is, for example, a mixed crystal represented by the following formula (2). . Moreover, this formula (2) can also be expressed by the following formula (2 ′). In Formula (2) and Formula (2 ′), M is Mn or Co. Here, the description of the formula (2) and the formula (2 ′) is a composition notation based on the stoichiometry, and as described above, as long as the perovskite structure can be taken, an unavoidable composition due to lattice mismatch, oxygen deficiency, etc. Deviation is allowed. For example, if the stoichiometry is 1, one in the range of 0.85 to 1.20 is allowed.
(1-x) [Bi (Fe _1-y M _y ) O ₃ ] -x [BaTiO ₃ ] (2)
(0 <x <0.40, 0.01 <y <0.09)
_{(Bi 1-x Ba x)} ((Fe 1-y M y) 1-x Ti x) O 3 (2 ')
(0 <x <0.40, 0.01 <y <0.09)

  Similarly to the first piezoelectric layer 71, the second piezoelectric layer 72 is made of a composite oxide containing Bi, Fe, Ba, and Ti and having a perovskite structure. The second piezoelectric layer 72 includes Ti and Ba of the second piezoelectric layer 72. The molar ratio (Ti / Ba) of the first piezoelectric layer 71 is larger than the molar ratio of Ti and Ba (Ti / Ba). The molar ratio of Ti to Ba (Ti / Ba) is preferably 1.45 or less, more preferably 1.17 or more and 1.45 or less. When Ti / Ba is set to 1.17 or more and 1.45 or less, the second piezoelectric layer 72 has a finer grain size and becomes a more uniform and dense film. In addition, the above-described composite oxide constituting the piezoelectric layer 70 preferably has a Bi to Ba molar ratio (Bi / Ba) of 2.3 or more and 4.0 or less.

The composite oxide composing the second piezoelectric layer 72 also has a perovskite structure, that is, an ABO ₃ type structure. In this structure, the A site is 12-coordinated with oxygen, and the B site is 6-coordinated with oxygen. To make an octahedron. The A site of the perovskite structure contains Bi and Ba, and the B site contains Fe and Ti.

  The composite oxide constituting the second piezoelectric layer 72 has, for example, a ratio (Bi + Ba) :( Fe + Ti) = 1: 1 between the total molar amount of Bi and Ba and the total molar amount of Fe and Ti. As long as the composite oxide composing the second piezoelectric layer 72 can have a perovskite structure, not only compositional deviation due to lattice mismatch, oxygen deficiency, etc., but also partial substitution of elements are allowed. Is done. As described above, Ti / Ba of the second piezoelectric layer 72 is larger than Ti / Ba of the first piezoelectric layer 71, and is preferably 1.45 or less. Further, Bi / Ba is preferably 2.3 or more and 4.0 or less. The composition of the second piezoelectric layer 72 is such that when the first piezoelectric layer 71 is a composite oxide represented by the above formula (1 ′), that is, the Ti / Ba of the first piezoelectric layer 71 is When it is 1, it can be represented by the following formula (3), for example. Here, the description of the formula (3) is a composition notation based on the stoichiometry. As described above, as long as the perovskite structure can be taken, the compositional deviation due to lattice mismatch, oxygen deficiency, etc. Partial replacement is also allowed. For example, if the stoichiometry is 1, one in the range of 0.85 to 1.20 is allowed.

(Bi _1-a Ba _a ) (Fe _1-b Ti _b ) O ₃ (3)
(1 <b / a, preferably 1.17 ≦ b / a ≦ 1.45, 2.3 ≦ (1-a) /a≦4.0.)

  Further, the composite oxide constituting the second piezoelectric layer 72 may also contain elements other than Bi, Fe, Ba, and Ti in order to improve desired characteristics. Examples of other elements include Mn and Co, and may include both Mn and Co. Of course, even a complex oxide containing other elements needs to have a perovskite structure.

  When the second piezoelectric layer 72 contains Mn and Co, it is assumed that Mn and Co are located at the B site, and that Mn and Co are complex oxides having a structure in which part of Fe located at the B site is substituted. Is done. For example, in the case where Mn is included, the composite oxide constituting the second piezoelectric layer 72 has the same basic characteristics as those not containing Mn or Co, but has leakage characteristics by containing Mn and Co. It will improve. Specifically, the occurrence of leak is suppressed. In addition, although Mn and Co have been described as examples, leakage characteristics can be improved in the same manner when transition metal elements such as Cr, Ni, and Cu are included or when two or more transition elements are included at the same time. These are also known to be the second piezoelectric layer 72, and may contain other known additives to improve properties.

  In the case of the complex oxide constituting the second piezoelectric layer 72, for example, the ratio of the total molar amount of the A site element to the total molar amount of the B site element (total molar amount of the A site element): (Total molar amount of B site element) = 1: 1, but as long as a perovskite structure can be obtained, not only compositional deviation due to lattice mismatch, oxygen deficiency, etc., but also partial substitution of elements is allowed Is done. In addition to Bi, Fe, Ba, and Ti, the composition of the second piezoelectric layer 72 made of a complex oxide having a perovskite structure including one or more of Mn, Co, and other transition metal elements is as follows. When the piezoelectric layer 71 is a composite oxide represented by the above formula (2 ′), for example, it is a mixed crystal represented by the following formula (4). In the formula (4), M ′ is a transition metal element such as Mn, Co, Cr, Ni, or Cu. Here, the description of the formula (4) is a composition notation based on stoichiometry, and as described above, compositional deviation due to lattice mismatch, oxygen deficiency, etc. is allowed as long as a perovskite structure can be taken. For example, if the stoichiometry is 1, one in the range of 0.85 to 1.20 is allowed.

(Bi _1-a Ba _a ) (Fe _1-bc M ′ _c Ti _b ) O ₃ (4)
(1 <b / a, preferably 1.17 ≦ b / a ≦ 1.45, 2.3 ≦ (1-a) /a≦4.0. 0 <c <0.09, preferably 0.01 ≦ c ≦ 0.05.)

The second piezoelectric layer 72 is made of other compounds having a perovskite structure, such as Bi (Zn, Ti) O ₃ , (Bi, K) TiO ₃ , (Bi, Na) TiO ₃ , (Li, Na, K) (Ta, Nb) O ₃ or the like may be contained.

  By using the piezoelectric layer 70 having the first piezoelectric layer 71 and the second piezoelectric layer 72 as described above, the second piezoelectric layer 72 is not provided as shown in the examples described later. The occurrence of cracks in the piezoelectric layer 70 can be suppressed. Therefore, the liquid jet head is excellent in reliability. Further, the piezoelectric layer 70 having the second piezoelectric layer 72 in this way is the same as the piezoelectric layer without the second piezoelectric layer 72, that is, the piezoelectric layer composed of only the first piezoelectric layer 71. The amount of strain can be obtained, and the amount of strain can be made larger than when only the second piezoelectric layer 72 is used. In other words, the piezoelectric layer 70 having the second piezoelectric layer 72 exhibits the effect of suppressing the generation of cracks, and Bi has a relatively large displacement amount among non-lead-based piezoelectric materials. The strain amount of the first piezoelectric layer 71 containing Ba, Fe, and Ti can be maintained.

  The thickness of the first piezoelectric layer 71 and the second piezoelectric layer 72 is not limited. For example, the thickness of the first piezoelectric layer 71 is 225 nm to 1125 nm. The thickness of the second piezoelectric layer 72 is 75 nm to 375 nm. The ratio between the thickness of the first piezoelectric layer 71 and the thickness of the second piezoelectric layer 72 is as follows: the thickness of the first piezoelectric layer 71: the thickness of the second piezoelectric layer 72 = 1: 0.2 to It is preferable to set it to 0.4.

  Each second electrode 80, which 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 extends to the elastic film 50 or an insulator film provided as necessary. For example, a lead electrode 90 made of gold (Au) or the like is connected.

  At least a part of the manifold 100 is formed on the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the first electrode 60, the elastic film 50, the insulator film provided as necessary, and the lead electrode 90. A protective substrate 30 having a manifold portion 31 constituting the above is joined 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 a member (for example, an elastic film 50, an insulator film provided as necessary, etc.) interposed between the flow path forming substrate 10 and the protective substrate 30 is provided. ) May be provided with an ink supply path 14 for communicating the manifold 100 and each pressure generating chamber 12.

  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 that faces 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.

  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.

  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 on the protective substrate 30. 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.

  In addition, a compliance substrate 40 including 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.

  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, 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.

  Next, an example of a method for manufacturing the ink jet recording head of the present embodiment will be described with reference to FIGS. 4 to 8 are cross-sectional views in the longitudinal direction of the pressure generating chamber.

First, as shown in FIG. 4A, a silicon dioxide film made of silicon dioxide (SiO ₂ ) or the like constituting the elastic film 50 is formed by thermal oxidation or the like on the surface of a flow path forming substrate wafer 110 that is a silicon wafer. To do. When an insulator film (not shown) made of zirconium oxide or the like is provided on the elastic film 50 or the like, it can be formed by, for example, a reactive sputtering method or thermal oxidation.

  Next, as shown in FIG. 4B, an adhesion layer 56 made of titanium oxide or the like is sputtered on the elastic film 50 (silicon dioxide film) or on the insulator film when an insulator film is provided. It is formed by ring method or thermal oxidation.

  Next, as shown in FIG. 5A, a first electrode 60 made of platinum, iridium, iridium oxide, or a laminated structure thereof is formed on the entire surface of the adhesion layer 56 by sputtering, vapor deposition, or the like. To do. Next, as shown in FIG. 5B, patterning is performed simultaneously on the first electrode 60 so that the side surfaces of the adhesion layer 56 and the first electrode 60 are inclined using a resist (not shown) having a predetermined shape as a mask.

  Next, after peeling off the resist, the piezoelectric layer 70 is laminated on the first electrode 60. Specifically, first, the first piezoelectric layer 71 is formed on the first electrode 60. The manufacturing method of the first piezoelectric layer 71 is not particularly limited. For example, the first piezoelectric layer 71 made of a metal oxide is obtained by applying and drying a solution containing a metal complex and firing at a high temperature. It can be produced by using a chemical solution method such as an organic decomposition method or a sol-gel method. In addition, laser ablation method, sputtering method, pulse laser deposition method (PLD method), chemical vapor deposition method (CVD method), aerosol deposition method, etc. One piezoelectric layer 71 can be manufactured.

  As a specific example of the formation procedure when the first piezoelectric layer 71 is formed by the chemical solution method, first, as shown in FIG. 5C, a metal complex, specifically, A MOD solution containing a metal complex containing Bi, Fe, Ba, and Ti or a precursor solution of a first piezoelectric layer made of a sol is applied using a spin coating method or the like to form a first piezoelectric precursor film 71a. Form (first piezoelectric layer coating step).

  The precursor solution of the first piezoelectric layer to be applied contains a metal complex capable of forming a complex oxide constituting the first piezoelectric layer 71 by firing, and in this embodiment, contains Bi, Fe, Ba, and Ti by firing. A metal complex capable of forming a composite oxide is mixed, and the mixture is dissolved or dispersed in an organic solvent. Further, when forming the first piezoelectric layer 71 made of a complex oxide containing Mn, Co or the like, a precursor solution containing a metal complex containing Mn, Co or the like is further used. The mixing ratio of each metal complex is such that each metal has a desired molar ratio, specifically, for example, a mixed oxide having a molar ratio of Ti and Ba (Ti / Ba) of 1 is obtained. Good. As the metal complex, for example, alkoxide, organic acid salt, β-diketone complex and the like can be used. Examples of the metal complex containing Bi include bismuth 2-ethylhexanoate and bismuth acetate. Examples of the metal complex containing Fe include iron 2-ethylhexanoate, iron acetate, and tris (acetylacetonato) iron. Examples of the metal complex containing Ba include barium isopropoxide, barium 2-ethylhexanoate, barium acetylacetonate, and the like. Examples of the metal complex containing Ti include titanium isopropoxide, titanium 2-ethylhexanoate, titanium (di-i-propoxide) bis (acetylacetonate), and the like. Examples of the metal complex containing Mn include manganese 2-ethylhexanoate and manganese acetate. Examples of the organometallic compound containing Co include cobalt 2-ethylhexanoate and cobalt (III) acetylacetonate. Of course, a metal complex containing two or more metals may be used. Examples of the solvent for the precursor solution include propanol, butanol, pentanol, hexanol, octanol, ethylene glycol, propylene glycol, octane, decane, cyclohexane, xylene, toluene, tetrahydrofuran, acetic acid, octylic acid, and the like.

Next, the first piezoelectric precursor film 71a is heated to a predetermined temperature (for example, 130 to 200 ° C.) and dried for a predetermined time (first piezoelectric layer drying step). Next, the dried first piezoelectric precursor film 71a is degreased by heating to a predetermined temperature (for example, 350 to 450 ° C.) and holding for a certain time (first piezoelectric layer degreasing step). The degreasing referred to here is to release the organic component contained in the first piezoelectric precursor film 71a as, for example, NO ₂ , CO ₂ , H ₂ O or the like. The atmosphere of the drying step or the degreasing step is not limited, and may be in the air, in an oxygen atmosphere, or in an inert gas. The first piezoelectric layer coating step, the first piezoelectric layer drying step, and the first piezoelectric layer degreasing step may be performed once, but the first piezoelectric layer coating step, the first piezoelectric layer drying step, You may perform a 1st piezoelectric material layer degreasing process in multiple times. In FIG. 5, a series of steps including a first piezoelectric layer coating step, a first piezoelectric layer drying step, and a first piezoelectric layer degreasing step are performed three times to form three layers of the first piezoelectric precursor film 71a. Laminated.

  Next, as shown in FIG. 5D, the first piezoelectric precursor film 71a is heated to a predetermined temperature, for example, about 600 to 850 ° C., and held for a certain time, for example, 1 to 10 minutes. To form a first piezoelectric film 71b made of a composite oxide containing Bi, Ba, Fe and Ti and having a perovskite structure (first piezoelectric layer firing step). In the present embodiment, since the operation of providing a plurality of first piezoelectric precursor films 71a and firing together is performed a plurality of times, as shown in FIG. 6A, from the plurality of first piezoelectric films 71b. The first piezoelectric layer 71 is formed. Even in the first piezoelectric layer firing step, the atmosphere is not limited, and may be in the air, in an oxygen atmosphere, or in an inert gas. As a heating device used in the first piezoelectric layer drying step, the first piezoelectric layer degreasing step, and the first piezoelectric layer firing step, for example, an RTA (Rapid Thermal Annealing) device or a hot plate for heating by irradiation with an infrared lamp. Etc.

  When forming the first piezoelectric layer 71 composed of the plurality of first piezoelectric films 71b, the first piezoelectric layer coating step, the first piezoelectric layer drying step, and the first piezoelectric layer as described above. After repeatedly performing the degreasing step, a plurality of layers may be baked together, but the first piezoelectric layer coating step, the first piezoelectric layer drying step, the first piezoelectric layer degreasing step, and the first piezoelectric body You may laminate | stack by performing a layer baking process in order. In the present embodiment, the first piezoelectric film 71b is provided by being laminated, but only one layer may be provided.

  Next, on the first piezoelectric layer 71, Ti / Ba, which is made of a complex oxide containing Bi, Fe, Mn, Ba and Ti and having a perovskite structure, is the molar ratio of Ti and Ba is the first piezoelectric layer. A second piezoelectric layer 72 higher than 71 is formed. The manufacturing method of the second piezoelectric layer 72 is not particularly limited, but, like the manufacturing method of the first piezoelectric layer 71, a solution containing a metal complex is applied and dried, and further baked at a high temperature to be made of a metal oxide. The second piezoelectric layer 72 can be manufactured using a chemical solution method such as a MOD method or a sol-gel method. In addition, laser ablation method, sputtering method, pulse laser deposition method (PLD method), chemical vapor deposition method (CVD method), aerosol deposition method, vapor phase method, liquid phase method and solid phase method, The second piezoelectric layer 72 can be manufactured.

  As a specific example of the formation procedure when the second piezoelectric layer 72 is formed by the chemical solution method, first, as shown in FIG. 6B, a metal complex, a specific example is formed on the first piezoelectric layer 71. The second piezoelectric precursor film is formed by applying a MOD solution containing a metal complex containing Bi, Fe, Ba, and Ti or a second piezoelectric layer precursor solution made of a sol using a spin coating method or the like. 72a is formed (second piezoelectric layer coating step).

  The precursor solution of the second piezoelectric layer to be applied contains a metal complex capable of forming a composite oxide constituting the second piezoelectric layer 72 by firing, and in this embodiment, contains Bi, Ba, Fe, and Ti by firing. A metal complex capable of forming a composite oxide is mixed, and the mixture is dissolved or dispersed in an organic solvent. Further, when forming the second piezoelectric layer 72 made of a complex oxide containing Mn, Co or the like, a precursor solution containing a metal complex containing Mn, Co or the like is further used. Specifically, the mixing ratio of each metal complex is a composite oxide in which the molar ratio of Ti and Ba (Ti / Ba) is larger than that of the first piezoelectric layer 71 so that each metal has a desired molar ratio. Thus, it is preferable to mix so that Ti / Ba is 1.17 or more and 1.45 or less, and the molar ratio of Bi to Ba (Bi / Ba) is 2.3 or more and 4.0 or less. . As the metal complex, for example, alkoxide, organic acid salt, β-diketone complex and the like can be used. Examples of the metal complex containing Bi include bismuth 2-ethylhexanoate and bismuth acetate. Examples of the metal complex containing Fe include iron 2-ethylhexanoate, iron acetate, and tris (acetylacetonato) iron. Examples of the metal complex containing Ba include barium isopropoxide, barium 2-ethylhexanoate, barium acetate, and barium acetylacetonate. Examples of the metal complex containing Ti include titanium isopropoxide, titanium 2-ethylhexanoate, titanium (di-i-propoxide) bis (acetylacetonate), and the like. Examples of the metal complex containing Mn include manganese 2-ethylhexanoate and manganese acetate. Examples of the organometallic compound containing Co include cobalt 2-ethylhexanoate and cobalt (III) acetylacetonate. Of course, you may use the metal complex containing 2 or more types of metals, such as Bi, Ba, Fe, and Ti. Moreover, as a solvent of the precursor solution of the second piezoelectric layer, propanol, butanol, pentanol, hexanol, octanol, ethylene glycol, propylene glycol, octane, decane, cyclohexane, xylene, toluene, tetrahydrofuran, acetic acid, 2-ethyl And hexanoic acid.

Next, the second piezoelectric precursor film 72a is heated to a predetermined temperature (for example, 150 to 200 ° C.) and dried for a predetermined time (second piezoelectric layer drying step). Next, degreasing is performed by heating the dried second piezoelectric precursor film 72a to a predetermined temperature (for example, 350 to 450 ° C.) and holding it for a certain time (second piezoelectric layer degreasing step). The degreasing referred to here is to release the organic component contained in the second piezoelectric precursor film 72a as, for example, NO ₂ , CO ₂ , H ₂ O or the like. The atmosphere of the second piezoelectric layer drying step and the second piezoelectric layer degreasing step is not limited, and may be in the air, in an oxygen atmosphere, or in an inert gas. The second piezoelectric layer coating step, the second piezoelectric layer drying step, and the second piezoelectric layer degreasing step may each be performed once, but the second piezoelectric layer coating step, the second piezoelectric layer drying step, You may perform a 2nd piezoelectric material layer degreasing process in multiple times. In FIG. 6B, a series of steps including a second piezoelectric layer coating step, a second piezoelectric layer drying step, and a second piezoelectric layer degreasing step are performed three times to obtain a second piezoelectric precursor film 72a. 3 layers were laminated.

  Next, as shown in FIG. 6C, the second piezoelectric precursor film 72a is heated to a predetermined temperature, for example, about 600 to 850 ° C., and held for a certain time, for example, 1 to 10 minutes. To form a second piezoelectric film 72b having a perovskite structure containing Bi, Ba, Fe, and Ti and made of a complex oxide with Ti / Ba higher than the first piezoelectric film 71b (second piezoelectric body) Layer firing step). In FIG. 6, since the plurality of second piezoelectric precursor films 72a are provided, the second piezoelectric layer 72 composed of the plurality of second piezoelectric films 72b is formed. The atmosphere of the second piezoelectric layer firing step is not limited, and may be in the air, in an oxygen atmosphere, or in an inert gas. Examples of the heating device used in the second piezoelectric layer drying step, the second piezoelectric layer degreasing step, and the second piezoelectric layer firing step include an RTA device and a hot plate that are heated by irradiation with an infrared lamp. When forming the second piezoelectric layer 72 composed of the plurality of second piezoelectric films 72b, as described above, the second piezoelectric layer coating step, the second piezoelectric layer drying step, and the second piezoelectric layer. After repeatedly performing the degreasing step, a plurality of layers may be baked together, but the second piezoelectric layer coating step, the second piezoelectric layer drying step, the second piezoelectric layer degreasing step, and the second piezoelectric body You may laminate | stack by performing a layer baking process in order. Further, in the present embodiment, the second piezoelectric film 72b is provided by being laminated, but only one layer may be provided.

  Such a piezoelectric layer 70 composed of the first piezoelectric layer 71 and the second piezoelectric layer 72 can be suppressed in the generation of cracks, as shown in examples described later. Also, the piezoelectric layer 70 having the predetermined second piezoelectric layer 72 can obtain the same amount of strain as that of the piezoelectric layer composed of only the first piezoelectric layer 71.

  Further, in such a manufacturing method, the second piezoelectric layer 72 is a first piezoelectric body made of a complex oxide containing Bi, Ba, Fe, and Ti and having a perovskite structure in the same manner as the second piezoelectric layer 72. Since the second piezoelectric layer 72 is provided on the layer 71, crystals can be continuously grown on the first piezoelectric layer 71.

  After the piezoelectric layer 70 is formed in this way, as shown in FIG. 7A, a second electrode 80 made of platinum or the like is formed on the piezoelectric layer 70 by a sputtering method or the like, and each pressure generating chamber is formed. Then, the piezoelectric layer 70 and the second electrode 80 are simultaneously patterned in a region facing 12 to form the piezoelectric element 300 having 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.

  Next, as shown in FIG. 7B, a lead electrode 90 made of, for example, gold (Au) or the like is formed over the entire surface of the flow path forming substrate wafer 110, and then a mask pattern made of, for example, a resist or the like. Patterning is performed for each piezoelectric element 300 via (not shown).

  Next, as shown in FIG. 7C, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is placed on the piezoelectric element 300 side of the flow path forming substrate wafer 110 via an adhesive 35. After the bonding, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, as shown in FIG. 8A, a mask film 52 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape.

  Then, as shown in FIG. 8B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH through the mask film 52 to form the piezoelectric element 300. Corresponding pressure generating chambers 12, communication portions 13, ink supply passages 14, communication passages 15 and the like are formed.

  Thereafter, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are removed by cutting, for example, by dicing. Then, after removing the mask film 52 on the surface opposite to the protective substrate wafer 130 of the flow path forming substrate wafer 110, the nozzle plate 20 having the nozzle openings 21 formed therein is bonded, and the protective substrate wafer 130 is also formed. The compliance substrate 40 is bonded to the substrate, and the flow path forming substrate wafer 110 or the like is divided into a single chip size flow path forming substrate 10 or the like as shown in FIG. To do.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to a following example.

(Sample 1)
First, a silicon dioxide film having a thickness of 1170 nm was formed by thermal oxidation on the surface of a single crystal silicon substrate oriented in (110). Next, a titanium film with a thickness of 20 nm was formed on the silicon dioxide film by RF magnetron sputtering, and a titanium oxide film was formed by thermal oxidation. Next, a platinum film having a film thickness of 130 nm was formed on the titanium oxide film by RF magnetron sputtering to form the first electrode 60.

  Next, a first piezoelectric layer 71 made of a complex oxide containing Bi, Ba, Fe, Mn, and Ti and having a perovskite structure was formed on the first electrode 60. The method is as follows. First, each n-octane solution of bismuth 2-ethylhexanoate, barium 2-ethylhexanoate, iron 2-ethylhexanoate, manganese 2-ethylhexanoate, and titanium 2-ethylhexanoate was mixed, and Bi: Ba: The first piezoelectric was mixed so that the molar ratio of Fe: Mn: Ti was Bi: Ba: Fe: Mn: Ti = 75.0: 25.0: 71.3: 3.8: 25.0 A body layer precursor solution was prepared.

  Next, a precursor solution of the first piezoelectric layer is dropped on the first electrode 60, rotated at 500 rpm for 5 seconds, then rotated at 3000 rpm for 20 seconds, and the first piezoelectric precursor film 71a by spin coating. Was formed (first piezoelectric layer coating step). Next, the substrate was placed on a hot plate and dried at 180 ° C. for 3 minutes (first piezoelectric layer drying step). Next, the substrate was placed on a hot plate and degreased at 350 ° C. for 3 minutes (first piezoelectric layer degreasing step). After repeating this first piezoelectric layer coating step, first piezoelectric layer drying step, and first piezoelectric layer degreasing step three times, firing was performed at 800 ° C. for 5 minutes in an RTA apparatus in an oxygen atmosphere. This was performed (first piezoelectric layer firing step). Next, the above-described steps were repeated three times, and the first piezoelectric layer 71 was formed by a total of nine coatings.

  Next, a second piezoelectric layer 72 made of a complex oxide containing Bi, Ba, Fe, Mn, and Ti and having a perovskite structure was formed on the first piezoelectric layer 71. The method is as follows. First, each n-octane solution of bismuth 2-ethylhexanoate, barium 2-ethylhexanoate, iron 2-ethylhexanoate, manganese 2-ethylhexanoate, titanium 2-ethylhexanoate was mixed, Bi, Ba, The second piezoelectric was mixed so that the molar ratio of Fe, Mn, and Ti was Bi: Ba: Fe: Mn: Ti = 75.0: 25.0: 71.3: 3.8: 25.0. A body layer precursor solution was prepared.

  Next, the second piezoelectric layer precursor solution is dropped on the first piezoelectric layer 71, rotated at 500 rpm for 5 seconds, then rotated at 3000 rpm for 20 seconds, and the second piezoelectric precursor by spin coating. A film 72a was formed (second piezoelectric layer coating step). Next, the substrate was placed on a hot plate and dried at 180 ° C. for 3 minutes (second piezoelectric layer drying step). Next, the substrate was placed on a hot plate and degreased at 350 ° C. for 3 minutes (second piezoelectric layer degreasing step). After repeating the process consisting of the second piezoelectric layer coating process, the second piezoelectric layer drying process, and the second piezoelectric layer degreasing process three times, firing was performed at 800 ° C. for 5 minutes in an RTA apparatus in an oxygen atmosphere. By performing, the 2nd piezoelectric material layer 72 was formed (2nd piezoelectric material layer baking process). Through the above steps, the first piezoelectric layer 71 having a thickness of 675 nm by applying the precursor solution of the first piezoelectric layer nine times and the thickness of 225 nm by applying the precursor solution of the second piezoelectric layer three times. A piezoelectric layer 70 composed of the second piezoelectric layer 72 was formed.

Thereafter, a platinum film having a film thickness of 100 nm is formed as the second electrode 80 on the piezoelectric layer 70 by DC sputtering, and then fired at 700 ° C. for 5 minutes under an O ₂ flow using an RTA apparatus. A piezoelectric element was formed.

(Samples 2-9)
The same operation as Sample 1 was performed except that the molar ratio of Bi: Ba: Fe: Mn: Ti in the precursor solution of the second piezoelectric layer was changed to the composition ratio shown in Table 1. Table 1 also shows the Ti / Ba value, which is the molar ratio of Ti and Ba.

(Test Example 1)
For Samples 1 to 9, the piezoelectric layer 70 before forming the second electrode 80 was observed with a scanning electron microscope (SEM) at a magnification of 50,000 times. As an example of the result, the result of SEM observation of sample 3 is shown in FIG. As a result, in Sample 1, the piezoelectric layer 70 is a single layer, but as shown in FIG. 9, in Samples 2-9, the boundary between the first piezoelectric layer 71 and the second piezoelectric layer 72 is clear. It had a layered structure.

(Test Example 2)
For Samples 1 to 9, “D8 Discover” manufactured by Bruker AXS was used, CuKα rays were used as the X-ray source, and the piezoelectric layer 70 composed of the first piezoelectric layer 71 and the second piezoelectric layer 72 at room temperature. The X-ray diffraction pattern of was obtained. An example of an X-ray diffraction pattern showing the correlation between diffraction intensity and diffraction angle 2θ is shown in FIGS. As a result, in all of Samples 1 to 9, a peak due to the perovskite structure and a peak derived from the substrate were observed. Specifically, the (100) peak due to the piezoelectric layer 70 having a single phase of the perovskite structure is near 23 °, the (110) peak is near 32 °, and the (111) peak due to platinum is present. It was confirmed around 40 ° and no heterogeneous phase was confirmed.

(Test Example 3)
In Samples 1 to 9, the piezoelectric layer 70 before forming the second electrode 80 was left for 5 days, and then the presence or absence of cracks in the piezoelectric layer 70 was confirmed. The surface of the piezoelectric layer 70 was observed with a 500 × metal microscope. The results are shown in Table 1.

  In Samples 2 to 9, where the molar ratio of Ti and Ba (Ti / Ba) of the second piezoelectric layer 72 is larger than the molar ratio of Ti and Ba of the first piezoelectric layer 71 (Ti / Ba), cracks occurred. It wasn't. On the other hand, in the sample 1 in which the second piezoelectric layer 72 and the first piezoelectric layer 71 are the same, cracks occurred.

(Test Example 4)
For each of the piezoelectric elements of Samples 1 to 9, an electrode pattern of φ = 500 μm was used at room temperature using a displacement measuring device (DBLI) manufactured by Azact Corporation, and a voltage of 30 V was applied at a frequency of 1 kHz. Displacement). The results are shown in Table 1.

  As a result, as shown in Table 1, Samples 2 to 9 in which Ti / Ba of the second piezoelectric layer 72 is larger than Ti / Ba of the first piezoelectric layer 71 are the second piezoelectric layer 72 and the first piezoelectric layer. Displacement amount does not decrease by providing the second piezoelectric layer 72 having the same displacement amount as that of the sample 1 having the same body layer 71 and Ti / Ba larger than Ti / Ba of the first piezoelectric layer 71. Was confirmed.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above. For example, in the above-described embodiment, the silicon single crystal substrate is exemplified as the flow path forming substrate 10, but the present invention is not particularly limited thereto, and for example, a material such as an SOI substrate or glass may be used.

  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 stacked on the substrate (the flow path forming substrate 10) is illustrated, but the present invention is not particularly limited thereto. For example, the present invention can also be applied to a longitudinal vibration type piezoelectric element in which piezoelectric materials and electrode forming materials are alternately stacked to expand and contract in the axial direction.

  In addition, the ink jet recording head of these embodiments constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 12 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus II shown in FIG. 12, the recording head units 1A and 1B having the ink jet recording head I are detachably provided with cartridges 2A and 2B constituting the ink supply means, and the recording head units 1A and 1B. Is mounted on a carriage shaft 5 attached to the apparatus main 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 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.

  In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and the liquid ejecting ejects a liquid other than ink. Of course, it can also be applied to the head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  Further, the piezoelectric element according to the present invention is not limited to the piezoelectric element used in the liquid ejecting head, and can be used in other devices. Other devices include, for example, an ultrasonic device such as an ultrasonic transmitter, an ultrasonic motor, a temperature-electric converter, a pressure-electric converter, a ferroelectric transistor, a piezoelectric transformer, and a filter for blocking harmful rays such as infrared rays. And filters such as an optical filter using a photonic crystal effect by quantum dot formation, an optical filter using optical interference of a thin film, and the like. The present invention can also be applied to a piezoelectric element used as a sensor and a piezoelectric element used as a ferroelectric memory. Examples of the sensor using the piezoelectric element include an infrared sensor, an ultrasonic sensor, a thermal sensor, a pressure sensor, a pyroelectric sensor, and a gyro sensor (angular velocity sensor).

  I ink jet recording head (liquid ejecting head), II ink jet recording apparatus (liquid ejecting apparatus), 10 flow path forming substrate, 12 pressure generating chamber, 13 communicating portion, 14 ink supply path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 manifold portion, 32 piezoelectric element holding portion, 40 compliance substrate, 50 elastic film, 60 first electrode, 70 piezoelectric layer, 71 first piezoelectric layer, 72 second piezoelectric layer, 80 second electrode , 90 lead electrode, 100 manifold, 120 drive circuit, 300 piezoelectric element

Claims (5)

A piezoelectric element comprising a piezoelectric layer and electrodes sandwiching the piezoelectric layer,
The piezoelectric layer is made of a complex oxide having a perovskite structure containing bismuth, iron, barium and titanium,
The piezoelectric layer has a first piezoelectric layer and a second piezoelectric layer,
The first piezoelectric layer is made of a complex oxide having a perovskite structure represented by the following formula (1) or (2):
The second piezoelectric layer is made of a complex oxide having a perovskite structure represented by the following formula (3) or (4).
(1-x) [BiFeO ₃ ] -x [BaTiO ₃ ] (1)
(0 <x <0.40)
(1-x) [Bi (Fe _1-y M _y ) O ₃ ] -x [BaTiO ₃ ] (2)
(0 <x <0.40, 0.01 <y <0.09 , M is Mn or Co )
(Bi _1-a Ba _a ) (Fe _1-b Ti _b ) O ₃ (3)
(1.20 ≦ b / a ≦ 1.45, 2.3 ≦ (1-a) /a≦4.0)
(Bi _1-a Ba _a ) (Fe _1-bc M ′ _c Ti _b ) O ₃ (4)
(1.20 ≦ b / a ≦ 1.45, 2.3 ≦ (1-a) /a≦4.0, 0 <c <0.09 , M ′ is Mn, Co, Cr, Ni, or Any of Cu ) A liquid ejecting head comprising the piezoelectric element according to claim 1 . A liquid ejecting apparatus comprising the liquid ejecting head according to claim 2 . An ultrasonic device comprising the piezoelectric element according to claim 1 . A sensor comprising the piezoelectric element according to claim 1 .