JP2013001680A - Process for production of composition for forming lanthanum nickelate film, process for production of lanthanum nickelate film, and process for production of piezo element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for production of a composition for forming a lanthanum nickelate film capable to produce a composition for forming a lanthanum nickelate film without requiring a particular environment, in a short period of time and at low cost, a process for production of the lanthanum nickelate film, and a process for production of a piezoelectric element.SOLUTION: The piezoelectric element 300 (actuator) is formed by laminating on an insulating film 55 a first electrode 60, a piezoelectric body layer 70 of 3 μm or less thickness, preferably 0.3-1.5 μm thin film placed above the first electrode 60, and a second electrode 80 placed on the piezoelectric body layer 70. The composition for forming a lanthanum nickelate film, that is the piezoelectric film 70, is produced by mixing lanthanum acetyl acetonate, nickel acetyl acetonate, acetic acid and water to give a mixed solution, then heating the mixed solution.

Description

  The present invention relates to a method for producing a composition for forming a lanthanum nickelate film, a method for producing a lanthanum nickelate film, and a method for producing a piezoelectric element.

  A piezoelectric element used in a piezoelectric device includes a piezoelectric material exhibiting an electromechanical conversion function, for example, a structure in which a ferroelectric layer made of a crystallized dielectric material is sandwiched between two electrodes. In such a piezoelectric element, a lanthanum nickelate layer may be used. Specifically, since the lanthanum nickelate layer exhibits high electrical conductivity at room temperature, it can be used as an oxide electrode. In addition, it is known that the lanthanum nickelate layer is naturally oriented (preferential orientation) on the (001) plane. On the oriented lanthanum nickelate layer, zirconate titanate having a relatively close crystal structure and lattice constant. It is known that by growing a ferroelectric layer typified by lead acid (PZT), the orientation of the ferroelectric layer can be controlled, and also functions as an orientation control layer (for example, Patent Documents). 1).

  Examples of a method for producing such a lanthanum nickelate layer (lanthanum nickelate film) include a gas phase method such as a sputtering method and a chemical solution method (CSD method: Chemical Solution Deposition). However, the sputtering method, which is a vapor phase method, produces a lanthanum nickelate film by colliding, for example, ionized argon with an oxide target in a vacuum, and depositing the element thus ejected on the substrate. Since this method requires a high vacuum, there is a problem in that an increase in the size of the apparatus is inevitable and costs increase.

  On the other hand, in the chemical solution method, a precursor solution (a composition for forming a lanthanum nickelate film) containing a metal element having a target composition is used to form a film on a substrate by, for example, a spin coating method, a dip coating method, or an ink jet method. This is a technique for producing a lanthanum nickelate film by firing (see, for example, Patent Document 2). Since this method does not require a high vacuum, it can be manufactured with a small apparatus.

JP 2007-043095 A JP 2008-251916 A

However, in the method for producing a composition for forming a lanthanum nickelate film as described in Patent Document 2, there is a problem that a special environment (such as under an N ₂ atmosphere) is required for synthesis, and a long time is required for synthesis. There was a problem that it took.

  In view of such circumstances, the present invention provides a method for producing a lanthanum nickelate film forming composition that can produce a lanthanum nickelate film forming composition in a short time and at a low cost without requiring a special environment, and nickel acid An object of the present invention is to provide a method for manufacturing a lanthanum film and a method for manufacturing a piezoelectric element.

An aspect of the present invention for solving the above-described problem is that lanthanum nickelate is characterized in that lanthanum acetylacetonate, nickel acetylacetonate, acetic acid, and water are mixed to obtain a mixed solution, and then the mixed solution is heated. It exists in the manufacturing method of the composition for film formation.
In such an embodiment, a lanthanum nickelate film forming composition can be produced in a short time and at a low cost without requiring a special environment.

  Here, it is preferable that the molar ratio (acetic acid / water) of the acetic acid and the water in the mixed solution is 0.6 or more and 6.3 or less. According to this, lanthanum acetylacetonate and nickel acetylacetonate can be easily dissolved in a mixed solution of acetic acid and water, and a composition for forming a lanthanum nickelate film can be efficiently produced.

Another aspect of the present invention includes a step of applying the lanthanum nickelate film forming composition to form a lanthanum nickelate precursor film, and crystallizing the lanthanum nickelate precursor film by heating to form nickel acid Forming a lanthanum film, and a method for producing a lanthanum nickelate film.
In such an embodiment, since the composition for forming a lanthanum nickelate film is stable, it is not necessary to perform strict environmental management, and a lanthanum nickelate film can be manufactured at low cost.

Another aspect of the present invention includes a step of forming a lanthanum nickelate layer by the above-described method of manufacturing a lanthanum nickelate film, and a step of forming a piezoelectric layer composed of a piezoelectric film above the lanthanum nickelate layer. And a piezoelectric element manufacturing method comprising:
In this aspect, a piezoelectric element including a lanthanum nickelate layer and a piezoelectric film can be manufactured at low cost. Moreover, since the composition for forming a lanthanum nickelate film is stable, it is not necessary to strictly manage the environment in the manufacturing process.

FIG. 5 is an exploded perspective view illustrating a schematic configuration of a recording head according to a second embodiment. FIG. 6 is a plan view and a cross-sectional view of a recording head according to Embodiment 2. 10 is a graph showing the XRD measurement result of Example 7.

(Embodiment 1)
The method for producing a composition for forming a lanthanum nickelate film of the present invention comprises mixing lanthanum acetylacetonate, nickel acetylacetonate, acetic acid, and water to obtain a mixed solution, and then heating the mixed solution to obtain nickel. A composition for forming a lanthanum acid film is obtained. As a result, a lanthanum nickelate film forming composition can be produced in a short time and at a low cost without requiring a special environment. The lanthanum nickelate film formed by this composition for forming a lanthanum nickelate film is naturally oriented (preferential orientation) on the (001) plane.

  Specifically, first, lanthanum acetylacetonate, nickel acetylacetonate, acetic acid, and water are mixed to obtain a mixed solution (mixed solution preparation step). When water is not mixed or acetic acid is not mixed, lanthanum acetylacetonate and nickel acetylacetonate cannot be dissolved, and the stability of the mixed solution is deteriorated.

  The mixed solution according to the present invention is obtained by dissolving lanthanum acetylacetonate and nickel acetylacetonate in acetic acid water in which acetic acid and water are mixed. The preparation method of a mixed solution is not specifically limited, For example, after mixing a predetermined amount of lanthanum acetylacetonate and nickel acetylacetonate, a mixed solution can be obtained by adding acetic acid and water to this. The method for mixing acetic acid and water is not particularly limited, and water may be added after adding acetic acid, acetic acid may be added after adding water, or acetic acid and water may be added after mixing. Also good.

In the mixed solution preparation step, lanthanum acetylacetonate and nickel acetylacetonate are mixed so that each metal of lanthanum (La) and nickel (Ni) has a desired molar ratio. Specifically, for example, when a lanthanum nickelate film of LaNiO _x (x = 2 to 3) is to be formed, lanthanum acetylacetonate and nickel so that the molar ratio of lanthanum: nickel is 1: 1. Mix with acetylacetonate.

  In the mixed solution preparation step, the molar ratio of acetic acid and water (acetic acid / water) in the mixed solution is preferably adjusted to be, for example, 0.6 or more and 6.3 or less. By setting this range, lanthanum acetylacetonate and nickel acetylacetonate can be easily dissolved in acetic acid mixed with acetic acid and water, and a lanthanum nickelate film forming composition can be produced efficiently. This is because it can.

In the mixed solution preparation step, the metal concentration of the mixed solution is preferably adjusted to 0.5 mol / L or less, and preferably adjusted to be 0.1 mol / L or more and 0.5 mol / L or less. More preferred. By setting the metal concentration of the mixed solution to 0.5 mol / L or less, a composition for forming a lanthanum nickelate film that is more suitable for forming a lanthanum nickelate film can be produced. Specifically, a composition for forming a lanthanum nickelate film having a viscosity suitable for forming a lanthanum nickelate film can be obtained, and a lanthanum nickelate film having a uniform film thickness and good film uniformity can be easily obtained. It can be formed. In addition, if it is less than 0.1 mol / L, the shrinkage rate of the film when forming the lanthanum nickelate film, specifically, the residual shrinkage rate of the lanthanum nickelate precursor film in the degreasing process described later increases. The stress is likely to increase, and there is a risk that cracks are likely to occur in the lanthanum nickelate film.
It is easy to cause cracks in the lanthanum nickelate film.

  Next, the obtained mixed solution is heated (heating step). Thereby, reaction progresses and the composition for lanthanum nickelate film | membrane formation which consists of a complex solution containing a predetermined metal complex can be obtained. In the present invention, the synthesis time (heating time) can be significantly shortened compared to the conventional heating time (synthesis time described in Patent Document 2). In this embodiment, the mixed solution was heated at 70 ° C. for 1 hour to obtain a lanthanum nickelate film forming composition.

  Moreover, the composition for forming a lanthanum nickelate film may be added with a solvent or the like, if necessary.

As described above, in the method for producing a lanthanum nickelate film forming composition of the present invention, the lanthanum nickelate film forming composition is synthesized in a system containing water. For this reason, unlike the conventional manufacturing method, it is not necessary to perform a dehydration treatment, and it is not necessary to synthesize in a special environment such as N ₂ atmosphere or Ar atmosphere in order to prevent reaction with water in the atmosphere. . Moreover, the composition for forming a lanthanum nickelate film can be synthesized in a short time. Furthermore, since a high vacuum is not required, it can be manufactured with a small device and can be manufactured at low cost.

  And the composition for lanthanum nickelate film formation obtained by the manufacturing method of the composition for lanthanum nickelate film formation of this invention is stable in the atmosphere containing water, and becomes easy to handle.

  The composition for forming a lanthanum nickelate film of the present invention is used as a coating solution for the CSD method (Chemical Solution Deposition). The CSD method, which will be described in detail later, is a step of forming a lanthanum nickelate precursor film by applying a composition for forming a lanthanum nickelate film, and crystallization by heating the lanthanum nickelate precursor film. A step of forming a lanthanum nickelate film, and examples thereof include a sol-gel method and a MOD method. In other words, the composition for forming a lanthanum nickelate film of the present invention can be suitably used for the MOD method or the sol-gel method.

Here, the manufacturing method of the lanthanum nickelate film | membrane using the composition for lanthanum nickelate film formation is demonstrated. Specifically, for example, a lanthanum nickelate film forming composition is applied onto an object by a spin coating method, a dip coating method, an ink jet method or the like to form a lanthanum nickelate precursor film (application step). Next, the lanthanum nickelate precursor film is heated to a predetermined temperature (for example, 100 ° C. or more and 250 ° C. or less) and dried for a predetermined time (drying step). Next, the dried lanthanum nickelate precursor film is degreased by heating to a predetermined temperature (for example, 300 ° C. or more and 500 ° C. or less) and holding it for a certain time (degreasing step). Here, degreasing refers, the organic components contained in the lanthanum nickelate precursor film, for example, is to be detached as _{NO 2, CO 2, H 2} O or the like. The atmosphere in the drying process or the degreasing process is not limited, and it may be in the air or in an inert gas.

  Next, the lanthanum nickelate precursor film is heated to a predetermined temperature (for example, 500 ° C. or higher and 800 ° C. or lower) and held for a certain period of time to crystallize to form a lanthanum nickelate film (firing step). Also in this firing step, the atmosphere is not limited, and may be in the air or in an inert gas.

  In addition, as a heating apparatus used by a drying process, a degreasing process, and a baking process, the RTA (Rapid Thermal Annealing) apparatus, a hotplate, etc. which heat by irradiation of an infrared lamp are mentioned, for example.

  In addition, what consists of a multiple layer lanthanum nickelate film | membrane by repeating the application | coating process, a drying process, a degreasing process mentioned above, a coating process, a drying process, a degreasing process, and a baking process several times according to desired film thickness etc. It is good. Thereby, a lanthanum nickelate film (LNO film) is formed.

Examples of the lanthanum nickelate film obtained by the manufacturing method described above include LaNiO ₃ , La ₃ Ni ₂ O ₆ , LaNiO ₂ , La ₂ NiO ₄ , La ₃ Ni ₂ O ₇ , La ₄ Ni ₃ O _{10 and the} like.

  As described above, by using the composition for forming a lanthanum nickelate film of the present invention, a lanthanum nickelate film can be formed by a chemical solution method, so that the composition deviates from the oxide used as a target as in the sputtering method. Thus, the lanthanum nickelate film can be easily manufactured at low cost without the need for a special environment. Moreover, since the composition for forming a lanthanum nickelate film is stable, it is not necessary to strictly manage the environment.

(Embodiment 2)
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 2 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 the drawing, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in the present embodiment, and on one surface thereof, a thickness 0.5 made of silicon dioxide constituting the diaphragm. An elastic film 50 of ˜2 μm is formed.

  A pressure generating chamber 12 is formed in the flow path forming substrate 10 by anisotropic etching from the other surface side which is the surface opposite to the one surface. The pressure generating chambers 12 partitioned by the plurality of partition walls 11 are arranged in parallel along the direction in which the plurality of nozzle openings 21 for discharging the same color ink are arranged in parallel. Hereinafter, this direction will be referred to as the juxtaposed direction of the pressure generating chambers 12 or the first direction, and the direction orthogonal thereto will be referred to as the second direction. In addition, an ink supply path 14 and a communication path 15 are partitioned by a partition wall 11 at one end side in the second direction of the pressure generating chamber 12 of the flow path forming substrate 10. In addition, a communication portion 13 that forms a part of the manifold 100 serving as an ink chamber (liquid chamber) common to the pressure generation chambers 12 is formed at one end of the communication passage 15. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, an ink supply path 14, a communication path 15, and a communication portion 13.

  The ink supply path 14 communicates with the one end side in the second direction of the pressure generation chamber 12 and has a smaller cross-sectional area than the pressure generation chamber 12. For example, in this embodiment, the ink supply path 14 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the manifold 100 and each pressure generation chamber 12 in the width direction. It is formed with. As described above, 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. Further, each communication path 15 communicates with the side of the ink supply path 14 opposite to the pressure generation chamber 12 and has a larger cross-sectional area than the width direction (first direction) of the ink supply path 14. In the present embodiment, the communication passage 15 is formed with the same cross-sectional area as the pressure generation chamber 12.

  That is, the flow path forming substrate 10 is provided with the pressure generation chamber 12, the ink supply path 14, and the communication path 15 that are partitioned by the plurality of partition walls 11. Further, one surface of the pressure generating chamber 12 of the flow path forming substrate 10 is defined by an elastic film 50 that constitutes a vibration plate.

  On the other hand, on one surface side of the flow path forming substrate 10 where the liquid flow path such as the pressure generation chamber 12 opens, a nozzle opening 21 communicating with the vicinity of the end of the pressure generation chamber 12 opposite to the ink supply path 14. The nozzle plate 20 in which is drilled is bonded via an adhesive, a thermal 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, an elastic film 50 made of silicon dioxide and having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10. For example, an insulator film 55 made of zirconium oxide (ZrO ₂ ) or the like is laminated.

  Further, on the insulator film 55, a first electrode 60 and a piezoelectric layer 70 which is provided above the first electrode 60 and is a thin film having a thickness of 3 μm or less, preferably 0.3 to 1.5 μm, The second electrode 80 provided above the piezoelectric layer 70 is laminated to form a piezoelectric element 300 (actuator). 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 the above-described example, the elastic film 50, the insulator film 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 Further, without providing the insulator film 55, only the first electrode 60 may function as a diaphragm. For example, when only the elastic film 50 is a diaphragm, the rigidity is lower than when the insulator film 55 is provided, so that the amount of displacement can be increased.

  Here, as shown in FIG. 2B, the first electrode 60 of the present embodiment includes, for example, a wiring layer 61 made of platinum and a lanthanum nickelate layer (LNO layer) 62 formed on the wiring layer 61. And is composed of two layers.

The lanthanum nickelate layer 62 is obtained by mixing the composition for forming a lanthanum nickelate film of Embodiment 1, specifically, lanthanum acetylacetonate, nickel acetylacetonate, acetic acid, and water to obtain a mixed solution. The lanthanum nickelate film forming composition obtained by heating the mixed solution is used. In the lanthanum nickelate layer 62, the crystal orientation plane is preferentially oriented (natural orientation) to the (001) plane. Examples of lanthanum nickelate include LaNiO ₃ , La ₃ Ni ₂ O ₆ , LaNiO ₂ , La ₂ NiO ₄ , La ₃ Ni ₂ O ₇ , La ₄ Ni ₃ O _10, etc. In this embodiment, LaNiO ₃ is used. Using.

  In the present embodiment, the wiring layer 61 is a platinum layer made of platinum. However, the wiring layer 61 is not limited to this. For example, iridium, an iridium oxide layer containing iridium oxide, a laminated structure of a platinum layer and an iridium oxide layer, or the like. Can be mentioned.

  The thickness of the wiring layer 61 is not particularly limited, but may be about 10 to 300 nm, for example. The thickness of the lanthanum nickelate layer 62 is not particularly limited, but may be, for example, about 10 to 100 nm. In this embodiment, the wiring layer 61 has a thickness of 100 nm, and the nickel lanthanum layer has a thickness of 40 nm.

The material of the piezoelectric layer 70 is not particularly limited. For example, a ferroelectric piezoelectric material having lead such as lead zirconate titanate (PZT), or niobium, nickel, magnesium, bismuth, yttrium, or the like. A relaxor ferroelectric or the like to which a metal is added is used. Also, barium titanate (BaTiO ₃ ), barium strontium titanate ((Ba, Sr) TiO ₃ ), bismuth ferrate (BiFeO ₃ ), bismuth barium manganate ferrate titanate ((Bi, Ba) (Fe, Ti) , Mn) O ₃ ), solid solution of lead magnesium niobate (PMN) and lead titanate (PT), or the like.

The piezoelectric layer 70 is preferably a complex oxide having a perovskite structure, that is, an ABO ₃ type structure. The perovskite structure is a structure in which oxygen is 12-coordinated at the A site and oxygen is 6-coordinated at the B site to form an octahedron.

  In the present embodiment, the piezoelectric layer 70 is made of lead zirconate titanate (PZT). The piezoelectric layer 70 is provided on the lanthanum nickelate layer 62 preferentially oriented in the (001) plane. Further, in the piezoelectric layer 70, the polarization direction indicating the direction in which the polarization moment is directed is perpendicular to the film surface (the thickness direction of the piezoelectric layer 70, that is, the surface on which the first electrode 60 or the second electrode 80 is provided). It is desirable that the engineered domain arrangement be inclined at a predetermined angle with respect to (perpendicular to the direction). Since the polarization direction of the piezoelectric layer 70 is an engineered domain arrangement, good piezoelectric characteristics can be obtained as the piezoelectric layer 70.

  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.

  The second electrode 80 of each piezoelectric element 300 is made of gold (Au) or the like drawn from the vicinity of the end on the ink supply path 14 side and extended on the insulator film 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.

  On the flow path forming substrate 10 on which the piezoelectric element 300 is formed, that is, on the first electrode 60, the elastic film 50, and the lead electrode 90, a protection having a manifold portion 31 constituting at least a part of the manifold 100. The substrate 30 is bonded via an adhesive 35. In this embodiment, the manifold portion 31 penetrates the protective substrate 30 in the thickness direction and is formed across the width direction of the pressure generating chamber 12. As described above, the communication portion 13 of the flow path forming substrate 10. The manifold 100 is configured as a common ink chamber for the pressure generation chambers 12.

  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 (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 41 seals one surface of the manifold portion 31. It has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). 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 of the present 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 the drive circuit 120. In accordance with the recording signal from the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, the elastic film 50, the insulator film 55, the first electrode 60, and the piezoelectric layer. By bending and deforming 70, the pressure in each pressure generating chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

A method for forming such a piezoelectric element 300 on the flow path forming substrate 10 is not particularly limited, but for example, it can be manufactured by the following method. First, a silicon dioxide film made of silicon dioxide (SiO ₂ ) or the like constituting the elastic film 50 is formed on the surface of a flow path forming substrate wafer that is a silicon wafer. Next, an insulator film 55 made of zirconium oxide or the like is formed on the elastic film 50 (silicon dioxide film).

  Next, the first electrode 60 is formed on the insulator film 55. Specifically, first, the wiring layer 61 is formed by sputtering, laser ablation, MOCVD, or the like. Next, a lanthanum nickelate layer 62 is formed. Since the method for forming the lanthanum nickelate layer 62 is the same as the method for manufacturing the lanthanum nickelate film of the first embodiment, the description thereof is omitted.

  Next, the piezoelectric layer 70 is stacked on the first electrode 60. The method for manufacturing the piezoelectric layer 70 is not particularly limited. For example, the piezoelectric layer 70 made of a metal oxide is formed by applying and drying a sol obtained by dissolving and dispersing an organometallic complex in a solvent, followed by baking at a high temperature. The piezoelectric layer 70 can be formed using a so-called sol-gel method. The method for manufacturing the piezoelectric layer 70 is not limited to the sol-gel method, and for example, a liquid phase method such as a MOD (Metal-Organic Decomposition) method, a PVD method, a CVD method, or the like may be used.

  For example, first, 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 applied onto the first electrode 60 by using a spin coating method or the like. Thus, a piezoelectric precursor film is formed (application process).

  The precursor solution to be applied is prepared by, for example, mixing organometallic complexes each containing a constituent metal of the piezoelectric material that becomes the piezoelectric layer 70 so that each constituent metal has a desired molar ratio, and mixing the mixture with an organic material such as alcohol. It is dissolved or dispersed using a solvent. As the organometallic complex containing the constituent metal of the piezoelectric material, for example, a metal alkoxide, an organic acid salt, a β-diketone complex, or the like can be used. Specific examples include the following. Examples of the organometallic complex containing lead (Pb) include lead acetate. Examples of the organometallic complex containing zirconium (Zr) include zirconium acetylacetonate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate and the like. Examples of the organometallic complex containing titanium (Ti) include titanium alkoxide and titanium isopropoxide.

Next, the piezoelectric precursor film 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 is degreased by heating it 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, for example, is to be detached as _{NO 2, CO 2, H 2} O or the like.

  Next, the piezoelectric precursor film is crystallized by heating to a predetermined temperature, for example, about 650 ° C. to 800 ° C. and holding it for a certain period of time to form a piezoelectric film (firing step). 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.

  In addition, by repeating the coating process, the drying process and the degreasing process described above, the coating process, the drying process, the degreasing process, and the firing process a plurality of times according to a desired film thickness, etc., a piezoelectric body composed of a plurality of layers of piezoelectric films. A layer may be formed.

  After the piezoelectric layer 70 is formed, a second electrode 80 made of, for example, a metal such as platinum is laminated on the piezoelectric layer 70, and the piezoelectric layer 70 and the second electrode 80 are simultaneously patterned to form the piezoelectric element 300. Form.

  Thereafter, post-annealing may be performed in a temperature range of 600 ° C. to 700 ° 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 further improved.

  In the present embodiment, the piezoelectric layer 70 is formed above the lanthanum nickelate layer 62 formed using the composition for forming a lanthanum nickelate film, so that a single crystal substrate or seed layer is not used and the cost is low. The piezoelectric layer 70 preferentially oriented in the (100) plane can be formed. In addition, since the composition for forming a lanthanum nickelate film used in this embodiment is stable, it is not necessary to perform strict environmental management in the manufacturing process.

  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
First, 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 heated and stirred for about 1 hour, and the composition for lanthanum nickelate film formation was manufactured.

(Example 2)
A lanthanum nickelate film forming composition of Example 2 was produced in the same manner as in Example 1 except that the amount of the acetic acid aqueous solution was changed to 10 ml.

(Example 3)
A lanthanum nickelate film forming composition of Example 3 was produced in the same manner as in Example 1 except that the acetic acid aqueous solution was changed to 100 ml.

Example 4
A lanthanum nickelate film forming composition of Example 4 was produced in the same manner as in Example 1 except that the acetic acid aqueous solution was changed to 83.3 ml and water was changed to 16.7 ml.

(Example 5)
A lanthanum nickelate film-forming composition of Example 5 was produced in the same manner as in Example 1 except that the acetic acid aqueous solution was changed to 41.7 ml and water was changed to 8.3 ml.

(Example 6)
A lanthanum nickelate film forming composition of Example 6 was produced in the same manner as in Example 1 except that the acetic acid aqueous solution was changed to 16.7 ml and water was changed to 3.3 ml.

(Comparative Example 1)
A composition for forming a lanthanum nickelate film of Comparative Example 1 was produced in the same manner as in Example 1 except that the amount of the acetic acid aqueous solution was 5 ml and water was not mixed.

(Comparative Example 2)
A composition for forming a lanthanum nickelate film of Comparative Example 2 was produced in the same manner as in Example 1 except that the amount of the acetic acid aqueous solution was 30 ml and water was not mixed.

(Comparative Example 3)
Take lanthanum nitrate hexahydrate _{(La (NO 3) 3 ·} 6H 2 O) in a beaker, and dried over 1 hour at 0.99 ° C. for the removal of hydrates. Next, after cooling to room temperature, 2-methoxyethanol was added, and the mixture was stirred at room temperature for 3 hours to dissolve lanthanum nitrate (solution A). Also, nickel acetate tetrahydrate ((CH ₃ COO) ₂ Ni · 4H ₂ O) was taken in another separable flask, dried at 150 ° C. for 1 hour to remove the hydrate, and then at 200 ° C. for 1 hour. Time was dried for a total of 2 hours. Next, 2-methoxyethanol and 2-aminoethanol were added, and the mixture was stirred at 110 ° C. for 30 minutes (solution B).

  After cooling the solution B to room temperature, the solution A is put into a separable flask containing the solution B. By stirring these mixed liquids at room temperature for 3 hours, the composition for forming a lanthanum nickelate film of Comparative Example 3 was produced.

  In Comparative Examples 1 and 2, lanthanum acetylacetonate and nickel acetylacetonate were not completely dissolved in acetic acid.

  In contrast, in Examples 1 to 6, the reaction was sufficiently advanced by heating for 1 hour, and the synthesis time was significantly shortened compared to the method for producing the lanthanum nickelate film forming composition of Comparative Example 3. It was confirmed that it was possible.

(Example 7)
First, a silicon dioxide film was formed on the surface of a silicon substrate by thermal oxidation. Next, a zirconium film was formed on the silicon dioxide film by sputtering and thermally oxidized to form a zirconium oxide film. Next, a wiring layer 61 was formed by laminating 150 nm of platinum oriented in the (111) plane on the zirconium oxide film.

  Next, a lanthanum nickelate film was formed on the wiring layer 61 using the composition for forming a lanthanum nickelate film of Example 1. Specifically, the lanthanum nickelate film forming composition (precursor solution) is dropped onto the substrate on which the titanium oxide film and the platinum film are formed, and the substrate is rotated at 3000 rpm to obtain the lanthanum nickelate precursor film. Was formed (application process). Next, it heated at 180 degreeC for 5 minutes, and 400 degreeC for 5 minutes (drying and degreasing process). Thereafter, it was baked and crystallized at 750 ° C. for 5 minutes in an oxygen atmosphere with an RTA (Rapid Thermal Annealing) apparatus, thereby forming a lanthanum nickelate layer 62 having a thickness of about 30 nm.

Next, the piezoelectric layer 70 was formed by a sol-gel method. The method is as follows. First, lead acetate trihydrate (Pb (CH ₃ COO) ₂ .3H ₂ O), titanium isopropoxide (Ti [OCH (CH ₃ ) ₂ ] ₄ ), zirconium acetylacetonate (Zr (CH ₃ COCHCOCH _{3 4} ) as a main raw material, butyl cellosolve (C ₆ H ₁₄ O ₆ ) as a solvent, diethanolamine (C ₄ H ₁₁ NO ₂ ) as a stabilizer, and polyethylene glycol (C ₂ H ₆ O ₆ ) as a thickener The mixed precursor solution was applied onto the first electrode 60 by spin coating to form a piezoelectric precursor film (application process). The precursor solution was lead acetate trihydrate: titanium isopropoxide: zirconium acetylacetonate: butyl cellosolve: diethanolamine: polyethylene glycol = 1.1: 0.44: 0.56: 3: 0.65: 0 .5 (molar ratio). Further, lead acetate trihydrate is added in excess of 10% in consideration of the decrease due to evaporation. Next, after heat treatment at 80 ° C. (drying step) and 360 ° C. (degreasing step), the piezoelectric precursor film is crystallized by baking at 700 ° C., and is composed of lead zirconate titanate having a thickness of 1300 nm. A piezoelectric layer 70 having the above was formed (firing step).

(Test Example 1)
The X-ray diffraction chart of Example 7 was obtained at room temperature using a “D8 Discover; micro-region X-ray diffractometer” manufactured by Bruker AXS, using CuKα rays as an X-ray source. FIG. 4 shows an X-ray diffraction pattern showing the correlation between diffraction intensity and diffraction angle 2θ in Example 7.

As a result, it was confirmed that the piezoelectric layer of Example 7 formed a perovskite type structure (ABO ₃ type structure). In the X-ray diffraction measurement (2θ / θ measurement), the (100) plane orientation ratio of the piezoelectric layer was calculated from the X-ray diffraction pattern resulting from the PZT crystal and the following calculation formula. Since the piezoelectric layer has a pseudo cubic structure, it is expressed as (100) plane here.

[Formula 1]
(100) plane orientation ratio (%) of piezoelectric layer = [area of diffraction peak of (100) plane of PZT crystal] / [sum of areas of all diffraction peaks caused by PZT crystal] × 100
The “area of the diffraction peak” was calculated by fitting, and the fitting function used was a pseudo-voice function which is a function of the sum of Gaussian and Lorentzian.

  As a result, the (100) plane orientation ratio of the piezoelectric layer of Example 7 was 99% or more, and it was confirmed that the (100) plane was preferentially oriented.

  In addition, it was confirmed that the piezoelectric layer formed by using the lanthanum nickelate composition of Example 1 which has passed for one month has been preferentially oriented in the (100) plane.

  Under the manufacturing conditions described above, it was confirmed that the piezoelectric layer can be preferentially oriented in the (100) plane by using the lanthanum nickelate film forming composition of Example 1. That is, it was confirmed that the lanthanum nickelate film formed using the composition for forming a piezoelectric ceramic film of Example 1 functions as an orientation control layer.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to what was mentioned above. For example, in the second embodiment, the first electrode 60 includes the wiring layer 61, but the wiring layer 61 may not be provided.

  In Embodiment 2 described above, the piezoelectric element used in the ink jet recording head has been described as an example of the piezoelectric element, but the lanthanum nickelate film forming composition of the present invention is represented by an ink jet recording head. The present invention is not limited to forming a piezoelectric element mounted on a liquid ejecting head, and can be suitably used for forming a lanthanum nickelate film of a piezoelectric element used for other piezoelectric devices.

  The lanthanum nickelate film formed by the composition for forming a lanthanum nickelate film of the present invention can be used particularly suitably as, for example, an electrode layer and / or an orientation control layer of a piezoelectric element.

  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).

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 13 Communication part, 14 Ink supply path, 15 Communication path, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board | substrate, 40 Compliance board | substrate, 50 Elastic film, 55 Insulator film | membrane, 60 First electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 manifold, 120 drive circuit, 300 piezoelectric element

Claims (4)

  A method for producing a composition for forming a lanthanum nickelate film, comprising mixing lanthanum acetylacetonate, nickel acetylacetonate, acetic acid, and water to obtain a mixed solution, and then heating the mixed solution.   2. The method for producing a lanthanum nickelate film forming composition according to claim 1, wherein a molar ratio (acetic acid / water) between the acetic acid and the water in the mixed solution is 0.6 or more and 6.3 or less. A method for producing a composition for forming a lanthanum nickelate film. Applying a lanthanum nickelate film forming composition produced by the method for producing a lanthanum nickelate film forming composition according to claim 1 or 2 to form a lanthanum nickelate precursor film;
Crystallization of the lanthanum nickelate precursor film by heating to form a lanthanum nickelate film;
The manufacturing method of the lanthanum nickelate film | membrane characterized by comprising. Forming a lanthanum nickelate layer by the method for producing a lanthanum nickelate film according to claim 3,
Forming a piezoelectric layer composed of a piezoelectric film above the lanthanum nickelate layer;
A method for manufacturing a piezoelectric element, comprising:

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