JP6098830B2 - Piezoelectric element, liquid ejecting head, liquid ejecting apparatus, ultrasonic device, filter 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. And in order to fully exhibit the piezoelectric characteristics of the piezoelectric layer, it is said that when the crystallinity is rhombohedral, it is desirable to be oriented in the (100) plane. For example, in order to orient lead zirconate titanate (PZT) in the (100) plane, a technique using seed titanium for a piezoelectric layer is known (see, for example, Patent Documents 1 to 3). Patent Document 1 discloses a method for manufacturing a piezoelectric element in which a piezoelectric layer made of lead zirconate titanate is formed on a lower electrode via a lead titanate layer. Patent Document 2 discloses a technique using lanthanum nickel oxide (LNO) as an orientation control layer for controlling the crystal orientation of a piezoelectric layer. Further, Patent Document 3 discloses a technique in which a buffer layer made of a metal element capable of forming a B site of a PZT crystal is (100) oriented as an orientation control layer.

  However, when manufacturing an ink jet recording head, the piezoelectric layer is formed on the underlying insulating layer such as silicon oxide or zirconium oxide in addition to the lower electrode. Even if the orientation control layer is used, there is a problem that the crystallinity of the piezoelectric layer changes, and the displacement characteristics and durability are lowered.

On the other hand, from the viewpoint of environmental problems, there is a demand for a piezoelectric material that suppresses lead-free or lead content. As a piezoelectric material not containing lead, for example, there is a BiFeO ₃ -based piezoelectric material containing Bi and Fe (see, for example, Patent Document 4), but there is a problem of crystallinity even in such a piezoelectric material. . In any case, the appearance of an orientation control layer that can effectively orient the crystals of the piezoelectric layer in the (100) plane is desired.

  Such a problem exists not only in an actuator device mounted on a liquid ejecting head such as an ink jet recording head but also in an actuator device mounted on another device.

JP 2011-238774 A Japanese Patent Laid-Open No. 2004-066600 JP 2005-340428 A JP 2007-287745 A

  In view of such circumstances, the present invention includes a liquid ejecting head that includes an orientation control layer that preferentially orients crystals of the piezoelectric layer in the (100) plane, and can improve the displacement characteristics and durability of the piezoelectric element. An object is to provide a liquid ejecting apparatus and a piezoelectric element.

An aspect of the present invention that solves the above problems includes a first electrode, a second electrode, and an orientation control layer and a piezoelectric layer provided between the first electrode and the second electrode, The piezoelectric layer is provided on the orientation control layer, and the orientation control layer is made of a complex oxide having a perovskite structure including bismuth, iron, and titanium, and the crystal of the piezoelectric layer is in the Z-axis direction ( The piezoelectric element is characterized in that crystal grains having a preferential orientation in the (100) plane and having the same orientation in the XY axis in-plane direction form a grain structure.
In such an embodiment, a piezoelectric element having a piezoelectric layer with good crystallinity and excellent displacement characteristics and durability is realized.

  Here, the piezoelectric layer is preferably a complex oxide having a perovskite structure including bismuth, barium, iron, and titanium. According to this, the crystal of the piezoelectric layer is more strongly oriented in the (100) plane in the Z-axis direction, and in the XY-axis in-plane direction, crystal grains having the same orientation form a grain structure as a whole. The crystallinity of the body layer becomes better.

  The piezoelectric layer preferably further contains manganese. This can improve the leakage characteristics of the piezoelectric layer.

  Moreover, it is preferable that the average diameter of the crystal grains (grain structure in which crystal grains having the same orientation are gathered) is 0.6 μm or less. According to this, the crystal of the piezoelectric layer is fine and dense, and the crystallinity is further improved.

  The piezoelectric layer is preferably a self-oriented crystal. According to this, the crystallinity of the piezoelectric layer is further improved.

Another aspect of the present invention is a liquid ejecting head that discharges liquid from a nozzle opening, and includes the piezoelectric element according to any one of the above aspects.
In such an embodiment, by providing an orientation control layer made of a composite oxide having a perovskite structure containing bismuth, iron and titanium, the crystals of the piezoelectric layer formed thereon are preferentially oriented in the (100) plane in the Z-axis direction. In the XY axis in-plane direction, crystal grains having the same orientation form a grain structure. As a result, the crystallinity of the piezoelectric layer is improved, and a liquid ejecting head having a piezoelectric layer excellent in displacement characteristics and durability is realized.
Another aspect of the present invention, there is provided a liquid-jet apparatus comprising the liquid ejecting head according to prior Kitai like. In such an embodiment, by providing an orientation control layer made of a composite oxide having a perovskite structure containing bismuth, iron and titanium, the crystals of the piezoelectric layer formed thereon are preferentially oriented in the (100) plane in the Z-axis direction. In the XY axis in-plane direction, crystal grains having the same orientation form a grain structure. Accordingly, a liquid ejecting apparatus including a liquid ejecting head having a piezoelectric layer having excellent crystallinity and excellent displacement characteristics and durability is realized.

According to another aspect of the present invention, there is provided an ultrasonic device, filter, or sensor comprising the piezoelectric element according to any one of the above aspects. In such an embodiment, the generation of cracks is suppressed, and an ultrasonic device, filter, or sensor having a piezoelectric layer in which crystals are strongly oriented in a specific orientation can be obtained.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. FIG. 3 is a diagram showing a TEM image of Example 1. The figure which shows the X-ray-diffraction pattern of Example 1 and Comparative Example 1. The grain boundary map which shows the surface photograph and crystal orientation of the piezoelectric material layer of Example 1 which were obtained by EBSD. The grain boundary map which shows the surface photograph and crystal orientation of the orientation control layer of Example 1 which were obtained by EBSD. The grain boundary map which shows the surface photograph and crystal orientation of the piezoelectric material layer of the comparative example 1 obtained by EBSD. FIG. 3 is a diameter distribution diagram of crystal grains of the piezoelectric layer according to the first embodiment. The graph which shows the result of the pulse durability evaluation of Example 1 and Comparative Example 1. 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 of an ink jet recording head which is an example of a liquid jet head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. 1 and a cross-sectional view taken along line AA ′ in FIG. . As shown in FIGS. 1 to 2, 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, and the elastic film 50 is made of, for example, zirconium oxide (ZrO ₂ ). Insulator layer 55 is laminated. Note that an adhesive layer made of titanium oxide or the like may be provided on the insulator layer 55 as necessary.

  On the insulator layer 55, the first electrode 60 is provided above the first electrode 60. The thickness is, for example, 20 to 80 nm, and the orientation control layer 65 is provided on the orientation control layer 65. The piezoelectric layer 70 which is a thin film having a thickness of 3 μm or less, preferably 0.3 to 1.5 μm, and the second electrode 80 provided above the piezoelectric layer 70 are laminated to form a piezoelectric layer. The element 300 is configured. In addition, the upper direction said here includes not only immediately above but the state where the other member intervened. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80.

  In the piezoelectric element 300, generally, one of the electrodes is a common electrode, and the other electrode is an independent electrode. In the present embodiment, the first electrode 60 is provided as an individual electrode of each piezoelectric active part that is a substantial driving part of the piezoelectric element 300, and the second electrode 80 is provided as a common electrode common to a plurality of piezoelectric active parts. I did it. Here, a portion where piezoelectric distortion is caused by application of voltage to both electrodes is referred to as a piezoelectric active portion, which is continuous from the piezoelectric active portion but is not sandwiched between the first electrode 60 and the second electrode 80, and is voltage driven. The part that is not used is called a piezoelectric non-active part. In addition, the piezoelectric element 300 and a vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric element, but may be referred to as an actuator device.

  In the above-described example, the elastic film 50, the insulator layer 55, and the first electrode 60 act as a diaphragm that is deformed together with the piezoelectric element 300. However, the present invention is not limited to this, and for example, the elastic film 50 In addition, without providing the insulator layer 55, only the first electrode 60 may function as a diaphragm. However, when the first electrode 60 is provided directly on the flow path forming substrate 10, it is preferable to protect the first electrode 60 with an insulating protective film or the like so that the first electrode 60 and the ink are not electrically connected.

The orientation control layer 65 of this embodiment is made of a complex oxide having a perovskite structure containing bismuth, iron, and titanium. Specifically, the A site of the ABO ₃ type structure has 12 coordinated oxygen, and the B site has 6 coordinated oxygen to form an octahedron. The complex oxide constituting the orientation control layer 65 is preferably basically composed of Bi at the A site and Fe and Ti at the B site.

  The preferred composition ratio of bismuth, iron, and titanium is preferably in the range of 40 ≦ x ≦ 60 when the element ratio is expressed as Bi: Fe: Ti = 100: x: (100−x).

  The orientation control layer 65 having such a configuration functions as the orientation control layer 65 that preferentially orients crystals of the piezoelectric layer 70 having a perovskite structure formed on the orientation control layer 65 in the (100) plane. More specifically, the crystal of the piezoelectric layer 70 is preferentially oriented in the (100) plane in the Z-axis direction, and crystal grains having the same orientation form a grain structure in the XY-axis in-plane direction. Here, the “Z-axis direction” refers to a direction along the film thickness direction of the piezoelectric layer 70, and the “XY-axis in-plane direction” refers to an arbitrary direction in a plane orthogonal to the Z-axis direction. Say. Further, “preferentially oriented in the (100) plane” means that all the crystals of the piezoelectric layer 70 are oriented in the (100) plane and most crystals (for example, 80% or more) ( 100) plane orientation. Further, “crystal grains having the same orientation form a grain structure” means that the individual crystals constituting the polycrystal gather together in the same orientation and form a lump of grains between the crystals.

  In the present invention, the crystal grain orientation is observed by data obtained by crystal orientation analysis by electron beam backscatter diffraction (EBSD), specifically, a grain boundary map. The average diameter (average particle diameter) of the crystal grains is a value calculated by image analysis of the grain boundary map.

  As described above, the crystal of the piezoelectric layer 70 is not only preferentially oriented in the (100) plane in the Z-axis direction, but crystal grains having the same orientation in the XY-axis in-plane direction form a grain structure. The crystallinity of the entire 70 film is improved. As a result, the displacement characteristics and durability of the piezoelectric element 300 having the piezoelectric layer 70 are improved as shown in examples described later.

  The average diameter of the crystal grains in the XY axis in-plane direction of the piezoelectric layer 70 is preferably 0.6 μm or less. When the average diameter of the crystal grains is 0.6 μm or less, the crystallinity of the piezoelectric layer 70 becomes dense and the crystallinity is further improved.

  In addition, since the orientation control layer 65 is formed after the first electrode 60 is patterned, the orientation control layer 65 is formed on the first electrode 60 and the insulator layer 55. The crystals of the piezoelectric layer 70 to be subsequently formed are preferentially oriented in the (100) plane in the Z-axis direction, and crystal grains having the same orientation form a grain structure in the XY-axis in-plane direction. As a result, even in the vicinity of the boundary between the first electrode 60 and the insulator layer 55, the nonuniformity of the crystal state of the piezoelectric layer 70 is reduced.

In addition, as long as the function as the orientation control layer 65 is not hindered, an oxide in which a part of elements of bismuth, iron, and titanium is substituted with another element may be included, and this is also included in the orientation control layer of the present invention. . For example, in addition to Bi, elements such as Ba, Sr, and La may further exist at the A site, and elements such as Zr and Nb may also exist along with Fe and Ti at the B site. In addition, as long as it has the above-described function, those that deviate from the stoichiometric composition (ABO ₃ ) due to deficiency or excess of the elements (Bi, Fe, Ti, O) are also included in the orientation control layer of the present invention.

  The orientation control layer 65 has a perovskite structure similar to that of the piezoelectric material forming the piezoelectric layer 70 described later, and has a small but piezoelectric property. The orientation control layer 65 and the piezoelectric layer 70 are combined. It can also be called a piezoelectric layer.

The piezoelectric layer 70 provided on the orientation control layer 65 is a piezoelectric material made of a complex oxide having a perovskite structure including bismuth, iron, barium, and titanium. Typically, the A site contains Bi and Ba, and the B site contains Fe and Ti. For example, a composite oxide having a perovskite structure composed of a mixed crystal of bismuth ferrate and bismuth titanate is used. Can be mentioned. 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. Examples of bismuth ferrates include bismuth ferrate (BiFeO ₃ ), bismuth ferrate aluminumate (Bi (Fe, Al) O ₃ ), bismuth ferrate manganate (Bi (Fe, Mn) O ₃ ), manganese ferrate Bismuth lanthanum oxide ((Bi, La) (Fe, Mn) O ₃ ), bismuth barium iron manganate titanate ((Bi, Ba) (Fe, Mn, Ti) O ₃ ), bismuth iron cobaltate (Bi) (Fe, Co) O ₃ ), bismuth cerium ferrate ((Bi, Ce) FeO ₃ ), bismuth cerium ferrate manganate ((Bi, Ce) (Fe, Mn) O ₃ ), bismuth lanthanum cerium ferrate ( _{(Bi, La, Ce) FeO} 3), bismuth lanthanum iron manganese oxide, cerium ((Bi, La, Ce) (Fe, Mn) O 3), bismuth ferrite, samarium ((Bi, S ) _FeO 3), ferrate chromic acid bismuth _{(Bi (Cr, Fe) O} 3), ferrate manganate bismuth potassium titanate ((Bi, K) (Fe , Mn, Ti) O 3), ferrate manganate And bismuth barium zinc titanate ((Bi, Ba) (Fe, Mn, Zn, Ti) O ₃ ).

Examples of the bismuth titanate include bismuth sodium titanate (Bi _1/2 Na _1/2 ) TiO ₃ , potassium bismuth sodium titanate ((Bi, Na, K) TiO ₃ ), and bismuth barium titanate. Sodium ((Bi, Na, Ba) (Zn, Ti) O ₃ ), sodium bismuth barium titanate ((Bi, Na, Ba) (Cu, Ti) O ₃ ) may be mentioned. Other examples include potassium bismuth titanate ((Bi, K) TiO ₃ ) and bismuth chromate (BiCrO ₃ ). In addition, for example, Bi (Zn _1/2 Ti _1/2 ) O ₃ , (Bi _1/2 K _1/2 ) TiO ₃ , (Li, Na, K) (Ta, Nb) O ₃ may be added. In the present embodiment, the composite oxide layer 72 is a composite oxide containing Bi, Fe, Ba, and Ti and having a perovskite structure.

The composite oxide having a perovskite structure containing Bi, Fe, Ba, and Ti is specifically a composite oxide having a perovskite structure of a mixed crystal of bismuth ferrate and barium titanate, or bismuth ferrate and titanium. It is also expressed as a solid solution in which barium acid is 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 or barium titanate, in addition to BiFeO ₃ or BaTiO ₃ , some elements (Bi, Fe, Ba, Ti, O) are partially lost or excessive, or some of the elements are other elements Although it is also known that it has been replaced with bismuth ferrate or barium titanate in this embodiment, it is deviated from the stoichiometric composition due to deficiency or excess unless the basic characteristics are changed. And those in which some of the elements are replaced with other elements are also included in the ranges of bismuth ferrate and barium titanate. Also, the ratio of bismuth ferrate manganate to barium titanate can be variously changed.

The composition of the piezoelectric layer 70 made of a composite oxide containing Bi, Fe, Ba and Ti and having a perovskite structure is represented by ((Bi, Ba) (Fe, Ti) O ₃ ). Typically, it is represented as a mixed crystal represented by the following general formula (1). Moreover, this formula (1) can also be represented by the following general formula (1 ′). Here, the description of the general formula (1) and the general formula (1 ′) is a composition notation based on stoichiometry, and as described above, as long as a perovskite structure can be taken, it is inevitable due to lattice mismatch, oxygen deficiency, etc. Of course, a partial substitution of elements is allowed as well as a slight compositional deviation. For example, if the stoichiometric ratio is 1, the range of 0.85 to 1.20 is allowed. In addition, even when the general formulas are different as described below, those having the same ratio of the A-site element to the B-site element may be regarded as the same composite oxide.

(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, when the piezoelectric layer 70 is a complex oxide having a perovskite structure including Bi, Fe, Ba, and Ti, an element other than Bi, Fe, Ba, and Ti may be further included. Examples of other elements include Mn, Co, and Cr. Of course, even a complex oxide containing other elements needs to have a perovskite structure. When the piezoelectric layer 70 includes Mn, Co, and Cr, Mn, Co, and Cr are complex oxides having a structure located at the B site. For example, when Mn is included, the composite oxide constituting the piezoelectric layer 70 has a structure in which part of Fe in a solid solution in which bismuth ferrate and barium titanate are uniformly dissolved, is substituted with Mn, or ferric acid It is expressed as a composite oxide having a perovskite structure of mixed crystals of bismuth manganate and barium titanate, and the basic characteristics are the same as those of a composite oxide having a perovskite structure of mixed crystals of bismuth ferrate and barium titanate. However, it has been found that the leakage characteristics are improved. Further, when Co or Cr is included, the leakage characteristics are improved in the same manner as Mn. In the X-ray diffraction pattern, bismuth ferrate, barium titanate, bismuth iron manganate, bismuth iron cobaltate, and bismuth iron chromate are not detected alone. Further, although Mn, Co and Cr 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 composition of the piezoelectric layer 70 made of a complex oxide having a perovskite structure including Mn, Co, and Cr in addition to Bi, Fe, Ba, and Ti is ((Bi, Ba) (Fe, Ti, Mn, Co, Cr) O ₃ ). Typically, it is represented as a mixed crystal represented by the following general formula (2). Moreover, this formula (2) can also be represented by the following general formula (2 ′). In General Formula (2) and General Formula (2 ′), M is Mn, Co, or Cr. Here, the description of the general formula (2) and the general formula (2 ′) is a composition notation based on the stoichiometry, and as described above, as long as the perovskite structure can be taken, it is unavoidable due to lattice mismatch, oxygen deficiency, etc. Such compositional deviation is acceptable. For example, if the stoichiometry is 1, one in the range of 0.85 to 1.20 is allowed. In addition, even when the general formulas are different as described below, those having the same ratio of the A-site element to the B-site element may be regarded as the same composite oxide.

(1-x) [Bi (Fe _{1- y My} ) O ₃ ] -x [BaTiO ₃ ] (2)
(0 <x <0.40, 0.01 <y <0.10)
_{(Bi 1-x Ba x)} ((Fe 1-y M y) 1-x Ti x) O 3 (2 ')
(0 <x <0.40, 0.01 <y <0.10)

  Note that the thickness of the piezoelectric layer 70 is not limited. For example, the thickness of the piezoelectric layer 70 is 3 μm or less, preferably 0.3 to 1.5 μm.

  The second electrode 80 may be any of various metals such as Ir, Pt, tungsten (W), tantalum (Ta), and molybdenum (Mo), and alloys thereof and metal oxides such as iridium oxide. It is done. Each second electrode 80 which is an individual electrode of the piezoelectric element 300 is extracted from the vicinity of the end on the ink supply path 14 side and extended on the insulator layer 55 of the flow path forming substrate 10. Lead electrodes 90 are connected to each other. A voltage is selectively applied to each piezoelectric element 300 via the lead electrode 90.

  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 insulator layer 55, the first electrode 60, and the piezoelectric material are applied. By flexing and deforming the body layer 70, the pressure in each pressure generating chamber 12 increases and ink droplets are ejected from the nozzle openings 21.

  Next, an example of a method for manufacturing the ink jet recording head of this embodiment will be described with reference to FIGS. 3 to 6 are cross-sectional views in the longitudinal direction (second direction) of the pressure generating chamber.

First, as shown in FIG. 3A, a silicon dioxide film made of silicon dioxide (SiO ₂ ) or the like that constitutes the elastic film 50 is formed on the surface of a wafer for flow path formation substrate that is a silicon wafer. Next, as shown in FIG. 3B, an insulator layer 55 made of zirconium oxide or the like is formed on the elastic film 50 (silicon dioxide film).

  Next, as shown in FIG. 4A, a first electrode 60 made of platinum is formed on the entire surface of the insulator layer 55 by sputtering or vapor deposition. Next, as shown in FIG. 4B, the first electrode 60 is patterned on the first electrode 60 using a resist (not shown) having a predetermined shape as a mask.

  Next, as shown in FIG. 4C, after the resist is peeled off, a precursor that becomes a composite oxide having a perovskite structure containing Bi, Fe, and Ti on the first electrode 60 (and the insulator layer 55). An alignment control layer precursor layer 66, which is a body, is formed and fired to obtain an alignment control layer 65 made of a complex oxide having a perovskite structure (FIG. 4D). Thus, the orientation control layer 65 is made of, for example, a metal oxide by applying a precursor solution containing a metal complex to form the orientation control layer precursor layer 66, drying it, and firing it at a higher temperature. The alignment control layer 65 can be obtained by using a chemical solution method such as a MOD (Metal-Organic Decomposition) method or a sol-gel method. In addition, the alignment control layer 65 can also be manufactured by a laser ablation method, a sputtering method, a pulse laser deposition method (PLD method), a CVD method, an aerosol deposition method, or the like.

  As an example of a specific forming procedure when forming the orientation control layer 65 by a chemical solution method, first, as shown in FIG. 4C, a MOD solution or sol containing a metal complex containing Bi, Fe and Ti is used. The composition for forming an orientation control layer (an orientation control layer precursor solution) is applied by spin coating or the like to form the orientation control layer precursor layer 66 (orientation control layer precursor solution coating step). .

  The precursor solution of the orientation control layer 65 to be applied is obtained by mixing a metal complex capable of forming a composite oxide containing Bi, Fe and Ti by firing, and dissolving or dispersing the mixture in an organic solvent. As a metal complex containing Bi, Fe, Ti, etc., for example, an alkoxide, an organic acid salt, a β-diketone complex, or 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 Ti include titanium 2-ethylhexanoate and titanium acetate. Of course, a metal complex containing two or more of Bi, Fe, Ti, etc. may be used. Examples of the solvent for the precursor solution of the orientation control layer 65 include propanol, butanol, pentanol, hexanol, octanol, ethylene glycol, propylene glycol, octane, decane, cyclohexane, xylene, toluene, tetrahydrofuran, acetic acid, octylic acid, and the like. Can be mentioned.

Next, the orientation control layer precursor layer 66 is heated to a predetermined temperature (for example, 150 to 200 ° C.) and dried for a predetermined time (alignment control layer drying step). Next, the dried alignment control layer precursor layer 66 is degreased by heating it to a predetermined temperature (for example, 350 to 450 ° C.) and holding it for a certain time (alignment control layer degreasing step). Degreasing as used herein refers to releasing the organic component contained in the orientation control layer precursor layer 66 as, for example, NO ₂ , CO ₂ , H ₂ O, or the like. The atmosphere of the orientation control layer drying step and the orientation control layer degreasing step is not limited, and may be in the air, in an oxygen atmosphere, or in an inert gas.

  Next, as shown in FIG. 4D, the orientation control layer precursor layer 66 is heated to a predetermined temperature, for example, about 600 to 850 ° C., and is maintained for a certain time, for example, 1 to 10 minutes for crystallization. Then, an orientation control layer 65 made of a composite oxide having a perovskite structure containing Bi, Fe, and Ti is formed (firing step).

  Also in this orientation control layer firing step, the atmosphere is not limited, and it may be in the air, in an oxygen atmosphere, or in an inert gas. Examples of the heating device used in the orientation control layer drying step, the orientation control layer degreasing step, and the orientation control layer firing step include an RTA (Rapid Thermal Annealing) device that heats by irradiation with an infrared lamp and a hot plate.

  In this embodiment, the orientation control layer 65 consisting of one layer is formed by applying the coating process once, but the orientation control layer coating process, the orientation control layer drying process, the orientation control layer degreasing process, and the orientation control layer coating process described above. The orientation control layer drying step, the orientation control layer degreasing step, and the orientation control layer firing step may be repeated a plurality of times depending on the desired film thickness and the like to form the orientation control layer 65 composed of a plurality of layers. However, in order not to reduce the displacement characteristics of the piezoelectric layer 70, the thinner one is preferable, and the thickness is preferably 20 nm to 80 nm, and more preferably 20 nm to 50 nm.

  Next, a piezoelectric layer 70 made of a complex oxide having a perovskite structure containing Bi, Fe, Ba, and Ti is formed on the orientation control layer 65. The piezoelectric layer 70 can be manufactured, for example, by applying and drying a solution containing a metal complex and degreasing. In addition, the piezoelectric layer 70 can be manufactured by a laser ablation method, a sputtering method, a pulse laser deposition method (PLD method), a CVD method, an aerosol deposition method, or the like.

  For example, first, as shown in FIG. 5A, a sol or MOD solution (precursor solution) containing an organometallic complex containing a constituent metal of a piezoelectric material to be the piezoelectric layer 70 is formed on the orientation control layer 65. The piezoelectric precursor film 71 is formed by coating using a spin coating method or the like (coating process).

  The precursor solution to be applied is obtained by mixing a metal complex capable of forming a composite oxide containing Bi, Fe, Ba and Ti by firing, and dissolving or dispersing the mixture in an organic solvent. Moreover, when forming the complex oxide layer 72 which consists of complex oxide containing Mn, Co, and Cr, the precursor solution containing the metal complex which contains Mn, Co, and Cr is further used. What is necessary is just to mix the mixing ratio of the metal complex which has a metal complex containing Bi, Fe, Ba, Ti, Mn, Co, and Cr so that each metal may become a desired molar ratio. As the metal complex containing Bi, Fe, Ba, Ti, Mn, Co, and Cr, 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. Examples of the organometallic compound containing Cr include chromium 2-ethylhexanoate. Of course, a metal complex containing two or more of Bi, Fe, Ba, Ti, Mn, Co, and Cr 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 piezoelectric precursor film 71 is heated to a predetermined temperature, for example, about 130 ° C. to 180 ° C. and dried for a predetermined time (drying step). Next, the dried piezoelectric precursor film 71 is degreased by heating to a predetermined temperature, for example, 300 ° C. to 400 ° C., and holding it for a certain time (degreasing step). Here, degreasing refers, the organic components contained in the piezoelectric precursor film 71, for _example, is to be detached as _{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. In addition, you may perform an application | coating process, a drying process, and a degreasing process in multiple times.

  Next, as shown in FIG. 5B, the piezoelectric precursor film 71 is crystallized by heating to a predetermined temperature, for example, about 650 to 800 ° C. and holding for a certain period of time, thereby forming a composite oxide layer 72. (Baking process). 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.

  The above-described coating process, drying process and degreasing process, and the coating process, drying process, degreasing process and firing process are repeated a plurality of times according to the desired film thickness and the like, thereby comprising a plurality of composite oxide layers 72. The piezoelectric layer 70 may be formed.

  Next, a piezoelectric body composed of a plurality of composite oxide layers 72 by repeating the above-described coating process, drying process, degreasing process, coating process, drying process, degreasing process, and firing process a plurality of times according to a desired film thickness and the like. By forming the layer 70, as shown in FIG. 5C, a piezoelectric layer 70 having a predetermined thickness composed of a plurality of composite oxide layers 72 is formed. For example, when the film thickness of the coating solution per one time is about 0.1 μm, for example, the total film thickness of the piezoelectric layer 70 composed of ten composite oxide layers 72 is about 1.1 μm. In the present embodiment, the composite oxide layer 72 is laminated, but only one layer may be provided.

  Thus, by forming the piezoelectric layer 70 having a perovskite structure containing Bi, Fe, Ba, and Ti on the orientation control layer 65 made of a composite oxide having a perovskite structure containing Bi, Fe, and Ti, the piezoelectric layer 70 is formed. These crystals are preferentially oriented in the (100) plane in the Z-axis direction, and crystal grains having the same orientation form a grain structure in the XY-axis in-plane direction. As a result, the crystallinity of the piezoelectric layer 70 becomes excellent, and the displacement characteristics and durability are improved as shown in the examples described later.

  After the piezoelectric layer 70 is formed, as shown in FIG. 6A, a second electrode 80 made of a metal such as platinum is laminated on the piezoelectric layer 70, and the piezoelectric layer 70 and the second layer The electrode 80 is simultaneously patterned to form the piezoelectric element 300. 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. 6B, a lead electrode 90 made of, for example, gold (Au) or the like is formed over the entire surface of the wafer 110 for flow path forming substrate, 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. 6C, 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 with an adhesive 35 interposed therebetween. After the bonding, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, although not shown, a mask film is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, by performing anisotropic etching (wet etching) using an alkaline solution such as KOH on the flow path forming substrate wafer 110 through the mask film, the pressure generating chamber 12 corresponding to the piezoelectric element 300, the communication portion 13, An ink supply path 14 and a communication path 15 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 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 bonded. The compliance substrate 40 is bonded, and the flow path forming substrate wafer 110 and the like are divided into a single chip size flow path forming substrate 10 and the like as shown in FIG. 1, thereby forming the ink jet recording head I of this embodiment. .

  In the present embodiment, the orientation control layer 65 is composed of a composite oxide containing Bi, Fe, and Ti, so that the crystal of the piezoelectric layer 70 containing Bi, Fe, Ba, and Ti formed thereon has a Z axis. The crystal grains are preferentially oriented in the (100) plane in the direction, and crystal grains having the same orientation form the grain structure in the XY axial direction. This is because the crystal growth of the perovskite structure of the piezoelectric layer 70 formed thereon is promoted by the orientation control layer 65 made of a complex oxide containing Bi, Fe, and Ti. Thereby, the crystallinity of the piezoelectric layer 70 of the present embodiment is excellent, and the displacement characteristics and durability are improved.

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

Example 1
<Preparation of substrate>
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 zirconium film having a thickness of 20 nm was formed on the silicon dioxide film by RF magnetron sputtering, and a zirconium oxide film was formed by thermal oxidation. Next, a zirconium film having a thickness of 10 nm is formed as an adhesion layer on the zirconium oxide film by RF magnetron sputtering, and a first electrode 60 made of a platinum film having a thickness of 130 nm is formed on the zirconium film by RF magnetron sputtering. Thus, a substrate with an electrode was obtained.

<Orientation control layer>
Each n-octane solution of bismuth 2-ethylhexanoate, iron 2-ethylhexanoate, and titanium 2-ethylhexanoate is mixed and mixed at a ratio of Bi: Fe: Ti of 100: 40: 60. Thus, an alignment control layer precursor solution was prepared.

The orientation control layer precursor solution is formed on the substrate with electrodes by a spin coater and then baked on a hot plate at 180 ° C. × 3 min and 350 ° C. × 3 min to form an amorphous film. Next, firing was performed at 700 ° C. for 5 minutes using a lamp annealing furnace to obtain an orientation control layer 65 having a thickness of 80 nm made of an oxide containing Bi, Fe, and Ti. When this orientation control layer (BiFeTiO ₃ layer) 65 is observed with a transmission electron microscope (TEM), it is confirmed that the orientation control layer (BiFeTiO ₃ layer) is a self-alignment film forming (100) orientation from the first atomic layer on the first electrode 60 side. It was done. The TEM image here is shown in FIG.

<Piezoelectric layer>
In order to form a piezoelectric layer composed of a composite oxide containing Bi, Ba, Fe, Ti and Mn and having a perovskite structure, bismuth 2-ethylhexanoate, barium 2-ethylhexanoate, iron 2-ethylhexanoate, Each n-octane solution of titanium 2-ethylhexanoate and manganese 2-ethylhexanoate was mixed, and the molar ratio of Bi: Ba: Fe: Ti: Mn was Bi: Ba: Fe: Ti: Mn = 75.0. : 25.0: 71.3: 25.0: 3.8 to prepare a piezoelectric layer precursor solution made of ((Bi, Ba) (Fe, Ti, Mn)).

  An appropriate amount of this piezoelectric layer precursor solution is taken into a micropipette and dropped onto the orientation control layer 65 of the electrode-attached substrate set on the spin coater. After forming a film with a spin coater, an amorphous film is formed by baking on a hot plate at 180 ° C. × 3 min and 350 ° C. × 3 min. The composite oxide layer 72 was obtained by firing at 750 ° C. for 5 minutes using a lamp annealing furnace.

  Similarly, in order to further produce the composite oxide layer 72, an appropriate amount of the piezoelectric layer precursor solution is taken into a micropipette and dropped onto a substrate with an electrode set on a spin coater. After film formation by a spin coater, an amorphous film is formed by baking on a hot plate at 180 ° C. × 3 min and 350 ° C. × 3 min. After repeating this operation twice, it was baked at 750 ° C. for 5 minutes using a lamp annealing furnace to obtain a crystal film. The steps up to the lamp annealing furnace were repeated five times to form a piezoelectric layer 70 having a thickness of about 900 nm, consisting of an orientation control layer and 12 composite oxide layers 72. A second electrode 80 made of iridium was formed on the piezoelectric layer 70 by sputtering.

(Comparative Example 1)
A lanthanum nickelate film was formed in place of the orientation control layer 65, and a lanthanum nickelate film was formed in the same manner as in Example 1 except that 12 complex oxide layers were laminated on the lanthanum nickelate film. Then, a piezoelectric layer having a thickness of about 900 nm composed of 12 complex oxide layers was formed.

The lanthanum nickelate film was formed by the following procedure. Lanthanum acetylacetonate (lanthanum acetylacetonate dihydrate (La (acac) ₃ ) · 2H ₂ O) and nickel acetylacetonate (nickel acetylacetonate dihydrate [Ni (acac) ₂ ] ₃ · 2H ₂ O) was added to the beaker such that lanthanum and nickel were each 0.005 mol. Thereafter, 25 ml of an acetic acid aqueous solution (99.7% by weight of acetic acid) was added, and 5 ml of water was further added and mixed. Then, it heated with the hotplate so that the temperature of a solution might be set to 70 degreeC, and it heated and stirred for about 1 hour, and prepared the precursor solution for lanthanum nickelate film formation.

  This precursor solution for forming a lanthanum nickelate film is formed on the substrate with the electrode by a spin coater and then baked on a hot plate at 180 ° C. × 3 min and 350 ° C. × 3 min to form an amorphous film. Next, firing was performed at 700 ° C. for 5 minutes using a lamp annealing furnace to obtain a lanthanum nickelate film having a thickness of 40 nm made of an oxide containing Ni and La.

(Test Example 1)
Using the “D8 Discover With GADDS: Micro-area X-ray diffractometer” manufactured by Bruker AXS, using CuKα ray as the X-ray source, and at room temperature, the X-ray diffraction chart of the example was formed before forming the second electrode. Asked. FIG. 8 shows the X-ray diffraction patterns of Example 1 and Comparative Example 1. Here, the peak near 2θ = 22.5 ° is a peak derived from the (100) plane, and the peak near 2θ = 31.8 ° is a peak derived from the (110) plane.

  As shown in FIG. 8, it was found that the piezoelectric layer of Example 1 provided on the orientation control layer was strongly oriented in the (100) plane. On the other hand, it was found that the piezoelectric layer of Comparative Example 1 provided on the lanthanum nickelate film was not oriented in the (100) plane but strongly oriented in the (110) plane.

  As a result, the composite oxide containing Bi, Fe and Ti serves as an orientation control layer for preferentially orienting the crystals of the piezoelectric layer containing Bi, Fe, Ba, Ti and Mn formed thereon on the (100) plane. I found it to work.

(Test Example 2)
Before the formation of the piezoelectric layer of Example 1 and the piezoelectric layer of Example 1 before forming the second electrode 80 using “Nodlys S: Electron Beam Backscattering Diffraction (EBSD)” manufactured by Oxford Instruments The crystal orientation of the piezoelectric layer of Comparative Example 1 before forming the orientation control layer and the second electrode 80 was measured. 9 to 11 show surface grain photographs and grain boundary maps showing crystal orientations obtained by measurement.

  As shown in FIG. 9A, FIG. 10A, and FIG. 11A, there are cracks on the surfaces of the piezoelectric layer and orientation control layer of Example 1 and the piezoelectric layer of Comparative Example 1. Did not occur.

  As shown in FIG. 9B, it was found that the crystal of the piezoelectric layer of Example 1 provided on the orientation control layer was strongly oriented in the (100) plane in the Z-axis direction. Further, as shown in FIG. 9C, in the XY axis in-plane direction, crystal grains having a uniform crystal orientation were observed, and it was observed that a grain structure was formed. Further, as shown in FIGS. 10B and 10C, the crystals of the orientation control layer before the piezoelectric layer is formed are also strongly oriented in the (100) plane in the Z-axis direction, and in the XY-axis in-plane direction. Then, it was observed that crystal grains having almost the same crystal orientation formed a grain structure. As a result, it has been found that the crystal orientation of the orientation control layer is inherited by the piezoelectric layer formed thereon in both the Z-axis direction and the XY-axis in-plane direction. Thereby, it was found that the crystallinity of the piezoelectric layer of Example 1 was good.

  On the other hand, as shown in FIGS. 11B and 11C, the crystal of the piezoelectric layer of Comparative Example 1 provided on the lanthanum nickelate film is not oriented in the (100) plane in the Z-axis direction, and XY The crystal orientation was found to be random even in the axial direction.

(Test Example 3)
By analyzing the data obtained by the electron beam backscatter diffraction method (EBSD) of Test Example 2, the average diameter (average particle diameter) of the crystal grains of the piezoelectric layer of Example 1 was calculated. For the average diameter, the diameter passing through the center of gravity of each crystal grain was measured in increments of 2 ° from the grain boundary map showing the crystal orientation obtained by EBSD measurement, and the average diameter of these diameters was determined. FIG. 12 shows a diameter distribution diagram of crystal grains in the XY-axis in-plane direction of Example 1.

  As shown in FIG. 12, the average diameter of the crystal grains in the XY-axis in-plane orientation of the piezoelectric layer of Example 1 was 0.586 μm. Thus, the average diameter of the crystal grains of the piezoelectric layer was found to be fine and dense. Furthermore, from Test Examples 1 and 2, such crystal grains are strongly oriented in the (100) plane in the Z-axis direction, and the crystal grains having a uniform crystal orientation form a grain structure in the XY-axis in-plane direction. Thereby, the crystallinity of the piezoelectric layer of Example 1 was improved, and it is considered that the displacement characteristics and durability were improved in Test Example 4 described later.

(Test Example 4)
Using the “pulse durability test apparatus”, pulse durability evaluation was performed using the piezoelectric elements of Example 1 and Comparative Example 1. FIG. 13 is a graph showing the results of pulse durability evaluation.

  As shown in FIG. 13, in the piezoelectric element of Example 1, when the initial displacement change rate was used as a reference, the displacement change rate did not decrease even when the number of pulses increased. On the other hand, in the piezoelectric element of Comparative Example 1, the displacement change rate decreased as the number of pulses increased. Thus, it was found that the displacement characteristics and durability of the piezoelectric element are improved by forming the orientation control layer with a composite oxide containing Bi, Fe, and Ti.

  As described above, from the results of Test Examples 1 to 4, by using a composite oxide containing bismuth, iron, and titanium as the orientation control layer, the crystal of the piezoelectric layer formed thereon is (100) in the Z-axis direction. It has been found that crystal grains that are strongly oriented in the plane and aligned in the XY axis plane form a grain structure. And it was found that the orientation-controlled piezoelectric layer has excellent crystallinity, and when used as a piezoelectric element, the displacement characteristics and durability are improved. Therefore, according to the present invention, it is possible to realize a highly reliable liquid ejecting head, liquid ejecting apparatus, and piezoelectric element with improved displacement characteristics and durability.

(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. 14 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus II shown in FIG. 14, the recording head units 1A and 1B having the ink jet recording head I are detachably provided with cartridges 2A and 2B constituting 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 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 conveying unit that conveys the recording sheet S is not limited to the conveying roller, and may be a belt, a drum, or the like.

  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 and an optical filter using optical interference of a thin film. 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), 10 flow path forming substrate, 12 pressure generating chamber, 13 communicating portion, 14 ink supply path, 15 communicating path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 40 compliance substrate , 50 elastic film, 55 insulator layer, 60 first electrode, 65 orientation control layer, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 manifold, 120 drive circuit, 300 piezoelectric element

Claims (10)

Comprising a first electrode, a second electrode, an orientation control layer and the piezoelectric layer disposed between the first electrode and the second electrode,
The piezoelectric layer is provided on the orientation control layer,
The orientation control layer is made of a composite oxide having a perovskite structure containing bismuth, iron and titanium,
The piezoelectric element is characterized in that crystals of the piezoelectric layer are preferentially oriented in the (100) plane in the Z-axis direction, and crystal grains having the same orientation form a grain structure in the XY-axis in-plane direction. 2. The piezoelectric element according to claim 1, wherein the piezoelectric layer is a complex oxide having a perovskite structure including bismuth, barium, iron, and titanium. The piezoelectric element according to claim 2, wherein the piezoelectric layer further contains manganese. 4. The piezoelectric element according to claim 1, wherein an average diameter of the grain structure formed by the crystal grains having the same orientation is 0.6 μm or less. The piezoelectric element according to any one of claims 1 to 4, characterized in that the piezoelectric layer is a crystalline for self-orientation. A liquid ejecting head for discharging liquid from a nozzle opening,
A liquid ejecting head, wherein the obtaining Bei piezoelectric element according to any one of claims 1 to 5. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 6 .   An ultrasonic device comprising the piezoelectric element according to claim 1.   A filter comprising the piezoelectric element according to claim 1.   A sensor comprising the piezoelectric element according to claim 1.