JP3955001B2 - Piezoelectric film forming composition and method for producing piezoelectric film - Google Patents

Description

  The present invention relates to a piezoelectric film forming composition, a piezoelectric film manufacturing method, a piezoelectric element, and an ink jet recording head.

  The piezoelectric element is made of a crystallized piezoelectric ceramic that is ferroelectric or paraelectric. The composition of the piezoelectric ceramic is generally composed of a two-component system mainly composed of lead zirconate titanate (hereinafter referred to as “PZT”), or a three-component system in which a third component is added to this two-component system PZT. A ferroelectric using a two-component PZT is described in [Non-Patent Document 1]. Examples of methods for producing these metal oxide type piezoelectric thin films include sputtering, MOCVD, and sol-gel.

  An ink jet printer head using a piezoelectric element formed by a sol-gel method is disclosed. For example, in [Patent Document 1], [Patent Document 2], [Patent Document 3], etc., a sol-gel method is used, and a sol containing a piezoelectric material is applied to a lower electrode in several times and heat treatment is repeated. Thus, a method of forming a piezoelectric thin film of a piezoelectric element used in an ink jet printer head is disclosed.

Japanese Patent Laid-Open No. 9-92897 Japanese Patent Laid-Open No. 10-139594 Japanese Patent Laid-Open No. 10-290035 Applied PhysicsLetters 1991.vol58 No11 pp1161-1163

  However, as a composition for forming a piezoelectric element by the sol-gel method, simply dissolving a normal metal complex or an organic acid metal salt in a solvent as it is is different in hydrolysis rate of the organic metal compound. By forming an oxide, it is difficult to obtain a uniform composition. Further, at the time of firing, the metal oxides are compounded by a solid phase reaction, but due to the difference in volatility of each, it is difficult to uniformly control the composition of the thin film. In addition, it is difficult to produce a piezoelectric element having a desired performance, such as a problem that a fine powdery film tends to be formed at the time of film formation and conduction is likely to occur.

  Regarding these problems, it is known to add a stabilizer to control rapid hydrolysis, which contributes to the stabilization of the coating solution and leads to the stabilization of the film formation.

  Conventionally, as stabilizers, β-diketones, ketone acids, lower alkyl esters of these ketone acids, oxyacids, lower alkyl esters of these oxyacids, oxyketones, α-amino acids, alkanolamines, etc. Is used. For example, the stabilizer stabilizes the metal alkoxide and / or metal salt by chelating and slows the hydrolysis reaction rate. For example, it is added for the purpose of obtaining a dense film by reacting an alkoxide such as Ti or Zr with acetylacetone to slow the hydrolysis reaction rate.

  However, even when the above stabilizers are used, the conversion from alkoxide to oxide is incomplete during firing, resulting in an incompletely densified film consisting of fine small particles, and more volatile metal components In some cases, satisfactory results have not yet been obtained, such as compositional fluctuations due to loss of silicon and variations in piezoelectricity. Further, when a film is formed using the above stabilizer, there is a disadvantage that the particle diameter of the thin film-forming particles is not uniform. In such a thin film having a non-uniform surface form, the piezoelectricity may be non-uniform depending on the location.

  Further, from the viewpoint of manufacturing a piezoelectric element, it is said that the larger the thickness of one layer formed, the better the efficiency, and a device for that purpose is required. In order to be used as an actuator, there is a demand for a dense film that uniformly exhibits characteristics as a piezoelectric element on the surface of the film and that has excellent durability. Further, when a thick film is formed, defects such as cracks are generated in the film, and the characteristics as an actuator are insufficient. Further, in the conventional method for producing a piezoelectric element forming composition, when stored for a long period of time, there is a problem of precipitation due to a polymerization reaction in the liquid, and thus it cannot be used stably for a long period of time. There is a case.

  An object of the present invention is to provide a piezoelectric element-forming composition, a piezoelectric film-forming method, a piezoelectric element, and an ink jet recording head that have few uneven portions of the surface form and can obtain good piezoelectric characteristics. It is said.

  The present invention provides 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2.2] as stabilizers. At least one of octane is used. This is due to electron donation from 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2.2] octane. , To stabilize metal alkoxides and / or metal salts. At the same time, the reactivity and solubility of the metal alkoxide and / or metal salt are changed to control the hydrolysis during the sol synthesis, the rate of the polycondensation reaction, and thereby the structure of the reaction product. As a result, it was found that the characteristics of the piezoelectric element were improved, the storage stability of the piezoelectric element forming composition was improved, and the performance of the ink jet recording head was improved, and the present invention was achieved.

  The piezoelectric element forming composition of the present invention is a piezoelectric element forming composition containing a dispersoid obtained from an organometallic compound for forming a piezoelectric element. It contains at least one of 8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, and 1,4-diazabicyclo [2.2.2] octane. Features.

  The composition for forming a piezoelectric element of the present invention comprises 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2. .2] The octane content is 0.005 times to 5.0 times the number of moles of total metal atoms in the piezoelectric element composition.

  The composition for forming a piezoelectric element of the present invention is characterized in that it contains at least one element selected from the elements Pb and La, Zr, and Ti as a constituent element.

  The method for manufacturing a piezoelectric element according to the present invention includes a step of applying the above-described composition for forming a piezoelectric element to a heat-resistant substrate and heating it in air, in an oxidizing atmosphere, or in a water-containing atmosphere. The film is fired at a temperature equal to or higher than the crystallization temperature at least during or after heating in the final step.

  An ink jet recording head of the present invention is an ink jet recording head including a piezoelectric element manufactured by the above-described piezoelectric element manufacturing method, and a pressure chamber substrate on which a pressure chamber is formed, and one of the pressure chambers. A diaphragm provided on a surface, and the piezoelectric element provided at a position corresponding to the pressure chamber of the diaphragm and configured to be able to change the volume of the pressure chamber. Features.

  According to the present invention, a piezoelectric element-forming composition, a piezoelectric film-forming method, a piezoelectric element, and a piezoelectric element-forming composition capable of obtaining excellent piezoelectric characteristics with few non-uniform surface shapes even when formed as a thick film An ink jet recording head can be provided.

  Hereinafter, modes for carrying out the present invention will be described.

  FIG. 1 is a diagram showing a configuration of an embodiment of a piezoelectric element of the present invention. In the figure, reference numeral 1 denotes a substrate.

  A semiconductor substrate made of silicon (Si), tungsten (W), or the like is preferably used, but ceramics such as zirconia, alumina, and silica may be used. An oxide layer, a nitride layer, or the like may be formed on the outermost surface.

  In FIG. 1, 2 and 4 are a lower electrode and an upper electrode, respectively, and in the present invention, are made of a conductive layer of about 5 to 500 nm. Specifically, metals such as Ti, Pt, Ta, Ir, Sr, In, Sn, Au, Al, Fe, Cr, and Ni and oxides thereof are used alone or in combination.

  These metals and oxides may be formed by coating and baking on a substrate by a sol-gel method or the like, or may be formed by sputtering or vapor deposition. Further, both the lower electrode and the upper electrode may be used after being patterned into a desired shape.

  In FIG. 1, reference numeral 3 denotes a piezoelectric thin film. In the present invention, in addition to Pb, a material containing at least one element from La, Zr, and Ti as a constituent element is manufactured and used by the sol-gel method. That is, after dissolving alkoxide and / or metal salt such as Pb, La, Zr, Ti, etc. in the solvent, water is added and hydrolyzed coating solution is coated on the substrate, dried, and then heat treatment It can be obtained by performing firing by a process.

Doping may be performed with a trace amount of elements other than Pb, La, Zr, and Ti. Specific examples include Ca, Sr, Ba, Sn, Th, Y, Sm, Ce, Bi, Sb, Nb, Ta, W, Mo, Cr, Co, Ni, Fe, Cu, Si, Ge, Sc, Mg, Mn, etc. are mentioned. Its content is represented by the general formula Pb _1-x La _x (Zr _y Ti _1-y ) O ₃ (where 0 ≦ x <1, 0 ≦ y ≦ 1)
The atomic fraction of metal atoms in is 0.05 or less.

  An organic metal compound used as a raw material for each component metal of the piezoelectric thin film is dispersed together in an appropriate organic solvent to form a composite organic metal oxide (an oxide containing two or more metals) that is a piezoelectric material. A raw material sol containing a precursor is prepared. The solvent for the sol is appropriately selected from various known solvents in consideration of dispersibility and coating properties.

  Solvents used include alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, s-butanol and t-butanol, ether solvents such as tetrahydrofuran and 1,4-dioxane, and 2-methoxyethanol. Cellosolve such as 2-ethoxyethanol, 1-methoxy-2-propanol, polyhydric alcohols such as diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, N, N-dimethylformamide, Examples thereof include amide solvents such as N, N-dimethylacetamide and N-methylpyrrolidone, and nitrile solvents such as acetonitrile. Of these, alcohol solvents are preferred. The amount of the solvent used in the sol-gel method in the present invention is usually 5 to 200 times mol, preferably 10 to 100 times mol, based on the metal alkoxide. If the amount of the solvent is too large, gelation is difficult to occur, and if it is too small, the heat generated during hydrolysis becomes intense.

  Pb alkoxide compounds include lead 2-ethoxyethoxide, lead methoxide, lead ethoxide, lead n-propoxide, lead i-propoxide, lead n-butoxyside, lead i-butoxyside, lead t-butoxyside, and other various types. Examples thereof include alkoxides and alkyl-substituted products thereof.

  In addition, Pb inorganic salt compounds, specifically chloride, nitrate, phosphate, sulfate, etc.Organic salt compounds specifically include formate, acetate, propionate, oxalate, citrate, Various carboxylates such as malates, hydroxycarboxylates, and acetylacetonate complexes may be mixed with a solvent to synthesize alkoxides in situ. The same alkoxide compound or inorganic salt can be used for La, Mg, Zr, Ti, and Nb. These alkoxide solutions or inorganic salts of Pb, La, Mg, Zr, Ti, and Nb are dissolved in the solvent and hydrolyzed to be polymerized to obtain a piezoelectric thin film coating solution.

The starting organometallic compound may be a complex organometallic compound containing two or more component metals in addition to the compound containing one kind of metal as described above. Examples of such complex organometallic compounds include PbO ₂ [Ti (OC ₃ H ₇ ) ₃ ] ₂ , PbO ₂ [Zr (OC ₄ H ₉ ) ₃ ] _{2 and the} like. In the present invention, the organometallic compound is used in a broad sense including a metal and an organic group, and is not used in a narrow sense having a carbon-metal bond.

Charge ratio of each metal, for example Pb, La, Zr, when using a Ti, Pb in _{(1-x) La x (} Zr y Ti 1-y) O 3 ( wherein, 0 ≦ x <1,0 ≦ However, since Pb disappears during the baking process during film formation, it is preferable to increase the amount of Pb at the time of preparing the coating liquid. Specifically, the molar ratio of Pb is 5% to 30% in Pb _(1-x) La _x (Zr _y Ti _1-y ) O ₃ (where 0 ≦ x <1, 0 ≦ y ≦ 1). You can increase it within the range.

  Next, a stabilizer is added to the mixed solution and stabilized. The metal-oxygen-metal bond is slowly polymerized as a whole. If a large amount of stabilizer is supplied, hydrolysis may not be performed properly, and precipitation may occur due to solubility problems.

  In the present invention, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.] Is used as a stabilizer in the organometallic compound solution of the composition for forming a ferroelectric thin film. [0] Add at least one of non-5-ene and 1,4-diazabicyclo [2.2.2] octane. If the content of the stabilizer in the organometallic compound solution is too small, the improvement effect due to the addition of these cannot be sufficiently obtained, and if too large, the viscosity increases and the film formability is inferior. This content is a concentration of 0.005 times mol or more and 5.0 times mol or less, particularly 0.05 times mol or more and 2.5 times mol or less with respect to the number of moles of total metal atoms. It is preferable. 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2.2] octane are used in combination. Also good. These may be used as a salt compound bonded to an acid. Specifically, formate, octylate and the like are known. In addition, β-diketones (for example, acetylacetone, heptafluorobutanoylpivaloylmethane, dipivaloylmethane, trifluoroacetylacetone, benzoylacetone, etc.), ketone acids ( For example, acetoacetic acid, propionylacetic acid, benzoylacetic acid, etc.), lower alkyl esters of these ketone acids such as ethyl, propyl, butyl, etc., oxyacids (eg, lactic acid, glycolic acid, α-oxybutyric acid, salicylic acid, etc.), these Lower alkyl esters of oxyacids, oxyketones (eg, diacetone alcohol, acetoin, etc.), α-amino acids (eg, glycine, alanine, etc.), alkanolamines (eg, diethanolamine, triethanolamine, monoethanolamine) ) Etc. And it may be.

  The amount of stabilizer used in the present invention is 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2. .2] When at least one of octane and the above-mentioned conventional stabilizer are used in combination, it is usually 0.05 to 5 times the moles of the total metal atoms, preferably The amount is from 0.1 to 1.5 times mol.

  The amount of the conventional stabilizer used in this case is 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo. [2.2.2] It is usually 0.01 to 20 times mole, preferably 0.05 to 10 times mole, relative to octane.

  For the hydrolysis of the solution containing the metal alkoxide and / or metal salt, for example, 0.05 to 30 moles of water of the metal alkoxide and / or metal salt is used, more preferably 0.5 to 15 moles. Molar water is used. For this hydrolysis, an acid catalyst and / or a base catalyst may be used. Preferably, a metal salt, a halide, a mineral acid such as sulfuric acid, nitric acid or hydrochloric acid, or an organic acid such as acetic acid is used as the acid catalyst. As the base catalyst, ammonia that can be easily removed by drying and calcination is often used.

  The hydrolysis reaction rate is determined depending on the type of metal alkoxide and / or metal salt, the type of solvent, the concentration of water relative to the metal alkoxide and / or metal salt, the concentration of metal alkoxide and / or metal salt, catalyst, metal alkoxide and / or It can be controlled by stabilizing the metal salt by chelation.

  After hydrolysis of the metal composition solution, the solvent having a boiling point of 100 ° C. or lower is completely removed, and the solvent having a boiling point of 100 ° C. or higher is added in an amount of 50% or higher. As the solvent used, cellosolve such as 1-methoxy-2-propanol, 2-ethoxyethanol, 3-methoxy-3-methylbutanol, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether Examples include polyhydric alcohols such as acetate, and fragrance oils such as terpineol, pine oil, and lavender oil. A cellosolve solvent is preferable. In addition, cellulose derivatives such as ethyl cellulose and hydroxypropyl cellulose, polymer resins such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl pyrrolidone derivatives, rosin, rosin derivatives, and the like may be used for the purpose of improving coatability.

  Thereafter, by adding a predetermined amount of stabilizer, the hydrolysis rate, polycondensation rate, etc. of the raw material solution can be suppressed and the aging stability can be improved without impairing the effect of improving the coatability and surface morphology. it can.

  The coating solution is applied on the lower electrode formed on the substrate and dried. As a coating method, a known coating method such as spin coating, dip coating, bar coating, spray coating, or the like can be used. In this case, the relative humidity is preferably 60% or less. If it is 60% or more, hydrolysis of the coating solution on the substrate proceeds rapidly and precipitates may be seen, which is not preferable.

  The film thickness per layer after drying is not particularly limited, but is preferably 0.01 μm to 5 μm. The total film thickness is preferably around 1 μm to 30 μm.

  Drying is performed at a temperature of 200 ° C. or lower. In this case, it is performed in the presence of a gas having a relative humidity of 10 to 70% at 25 ° C. If it is 70% or more, hydrolysis of the coating solution on the substrate proceeds rapidly, which is not preferable because it causes cracks. On the other hand, if it is 10% or less, hydrolysis does not proceed at all, and the temperature at the time of firing described later rises, which is not preferable. For this drying, a dryer, a dryer, a hot plate, a tubular furnace, an electric furnace or the like can be used. A gas having a relative humidity of 10 to 70% at 25 ° C. can be obtained by bubbling a desired gas into water. Moreover, you may introduce | transduce the gas adjusted using the humidifier etc.

  Subsequently, temporary baking is performed in the range of 200 ° C to 500 ° C. In this case, it is carried out in the presence of a gas having a relative humidity of 70 to 99% at 25 ° C. If it is 70% or less, hydrolysis does not proceed, which is not preferable. A dryer, a drier, a hot plate, a tubular furnace, an electric furnace, or the like can be used for this temporary baking. A gas having a relative humidity of 70 to 99% at 25 ° C. can be obtained by bubbling a desired gas into water. Moreover, you may introduce | transduce the gas adjusted using the humidifier etc.

  Further, the main baking is performed in the range of 500 ° C to 800 ° C. In this case, it is carried out in the presence of a gas having a relative humidity of 70 to 99% at 25 ° C. If it is 70% or less, hydrolysis does not proceed, which is not preferable. A tube furnace, an electric furnace, etc. can be used for this main baking. A gas having a relative humidity of 70 to 99% at 25 ° C. can be obtained by bubbling a desired gas into water. Moreover, you may introduce | transduce the gas adjusted using the humidifier etc.

  It is preferable that the gas containing moisture flows on the coating surface at a constant speed. If it stays, the hydrolysis of the coating solution is delayed, which is not preferable. A preferred flow rate on the substrate is 0.5 cm / sec to 50 cm / sec. However, if the area of the substrate is very small and there is a large excess of moisture-containing gas, there is no effect even if it stays.

  The film thickness after firing per layer formed by the coating liquid is not particularly limited, but is preferably 0.01 μm to 1 μm, and preferably 0.02 μm to 0.9 μm in view of workability. By repeating this operation, a piezoelectric thin film having an arbitrary film pressure can be obtained. The drying step must be performed for each layer, but the preliminary firing and the main firing may be performed for each layer or may be performed every several layers. Further, the main baking may be performed only at the end.

  The gas present on the substrate surface from the drying step to the main baking is preferably an oxygen-containing atmosphere, and the oxygen concentration is preferably between 20% and 100%. If it is less than 20%, the sintering does not proceed and the perovskite structure is not taken, and the desired performance does not appear.

  Further, a stepwise temperature increase may be performed during firing. By such firing, the organic component is almost lost, and a dense laterally formed piezoelectric film can be obtained.

  FIG. 2 is an enlarged view schematically showing a part of an ink jet printer head in which a piezoelectric element is used as an actuator, showing an example of an embodiment of the present invention. The basic configuration of the printer head is the same as that of the prior art, and is composed of a head base 5, a diaphragm 7, and a piezoelectric element. The head base 5 has a large number of ink nozzles (not shown) for ejecting ink, a large number of ink paths (not shown) individually communicating with the respective ink nozzles, and an individual communication with each ink path. A large number of ink chambers 6 are formed, and a vibration plate 7 is attached so as to cover the entire upper surface of the head base 5, and the upper surface openings of all the ink chambers 6 of the head base 5 are closed by the vibration plate 7. Has been. On the vibration plate 7, piezoelectric elements 8 for applying a vibration driving force to the vibration plate 7 are attached and formed at positions corresponding to the respective ink chambers 6. A number of piezoelectric elements 8 are controlled by a power source 9 to apply a voltage to a desired selected piezoelectric element 8, thereby displacing the piezoelectric element 8 and vibrating the diaphragm 7 in that portion. Let As a result, the volume of the ink chamber 6 corresponding to the vibration of the vibration plate 7 changes, and ink is pushed out from the ink nozzles through the ink path to perform printing.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

(Coating liquid production examples 1 to 11)
In this production example, as shown in Table 1, the metal composition is Pb _{1 + xy} La _y Zr _0.52 Ti _0.48 (where 0 ≦ x ≦ 0.3, 0 ≦ y <1) as the coating liquid for the piezoelectric thin film. The coating liquid represented by the above was prepared as follows.

  Lead acetate hydrate (Pb) and lanthanum acetate hydrate (La) were mixed and dehydrated, and 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non- 5-ene, 1,4-diazabicyclo [2.2.2] octane, 1,8-diazabicyclo [5.4.0] -7-undecene formate, 1,8-diazabicyclo [5.4.0] -7-undecene octyl One kind selected from acid salts and 1-methoxy-2-propanol (solvent 1) are mixed and reacted. Thereafter, 1,8-diazabicyclo [5.4.0] -7-undecene is DBU, 1,5-diazabicyclo [4.3.0] non-5-ene is DBN, and 1,4-diazabicyclo [2.2.2] octane is DABCO. Abbreviated. Thereafter, 0.52 mol of zirconia tetra-n-butoxide and 0.48 mol of titanium n-butoxide were added and further heated and reacted to complex the raw metal compounds with each other. Next, water and ethanol (solvent 2) were added to conduct a hydrolysis reaction. At that time, acetic acid and acetylacetone were added. Moreover, what added polyvinylpyrrolidone K-30 (PVP) as a film-forming auxiliary agent (Production Examples 5, 6, 7) was also prepared. Thereafter, the solvent having a boiling point of 100 ° C. or lower was completely removed with a rotary evaporator, and diethylene glycol monoethyl ether (solvent 3) was added to prepare a metal oxide concentration converted to the above composition formula to 10 wt%.

(Production Comparative Example 1)
In this production example, a coating solution for a piezoelectric thin film was prepared in the same manner as in Production Example 2 except that diisopropylethylamine was added instead of DBU.

(Production Comparative Example 2)
In this production example, lead acetate hydrate (Pb) and lanthanum acetate hydrate (La) were mixed and dehydrated, and zirconia-isopropoxide and titanium-isopropoxide were added and reacted. Thereafter, a coating liquid for a piezoelectric thin film was prepared in the same manner as in Production Example 5 except that diaminoethanol was added instead of DBU.

(Production Comparative Example 3)
In this comparative example, a coating liquid for a piezoelectric thin film was prepared in the same manner as in Production Example 2 except that the synthesis was performed without adding DBU. When this coating solution was allowed to stand, a white crystal was precipitated.

(Examples 1-9)
It was obtained in the above coating liquid production examples 1, 3, 4, 6, 7, 8, and 9 on the surface of a zirconia substrate (3 cm square) in which a part of the back surface was hollowed out as shown in FIGS. The coating liquid was applied by a spin coating method, and air having a relative humidity of 35% was dried at 25 ° C. in air at 100 ° C. for 5 minutes (drying step). Then, 400 ° C for 5 minutes while flowing a gas containing 30% oxygen and 70% nitrogen at a flow rate of 20cm / sec at 25 ° C in a tubular furnace of 5cm in diameter and 100cm in length (inner heater section 30cm) ), 650 ° C. for 5 minutes under the same atmosphere (main firing step). After repeating this coating and heating three times, finally, firing was performed at 700 ° C. for 40 minutes in a tubular furnace at 25 ° C. in a gas atmosphere containing 30% oxygen and 70% nitrogen at a relative humidity of 75% (main firing step). ) And then cooled to room temperature under the same humidity environment (cooling step) to obtain the piezoelectric element of the present invention. (FIG. 5) When the metal composition of the intermediate part of the piezoelectric thin film was analyzed, it was Pb _1.0 Zr _0.52 Ti _0.48 .

  The film thickness after coating and baking three times is as follows.

(Examples 10 to 11)
The coating liquid obtained in the above coating liquid production examples 2 and 5 was applied to the same substrate as in Examples 1 to 4 by spin coating, and the relative humidity was 50% at 100C and 5 minutes in the air at 25C. Dried (drying process). Then, this was heated in a tube furnace with a diameter of 5cm and a length of 100cm (inner heater section 30cm) at 25 ° C in a gas atmosphere containing 90% relative humidity and 30% oxygen and 70% oxygen (preliminary firing process) at 300 ° C for 20 minutes. And heating three times, and finally, in order to crystallize the thin film, the tube furnace was fired at 750 ° C. for 40 minutes in a gas atmosphere containing 40% oxygen at 60% relative humidity and 60% nitrogen at 25 ° C. Step) and then cooled to room temperature under the same humidity environment (cooling step). A piezoelectric element of the present invention was obtained. Analysis of the metal composition in the middle part of the piezoelectric thin film revealed Pb _0.99 La _0.01 Zr _0.52 Ti _0.48 . The film thickness after coating and baking three times is as follows.

(Example 12)
In this example, air having a relative humidity of 60% at 25 ° C. was used for 5 minutes in drying at 150 ° C., and then air having an relative humidity of 80% at 25 ° C. was raised from 400 ° C. to 600 ° C. The piezoelectric element of the present invention was obtained in the same manner as in Example 6 except that the temperature was increased at a rate of 2 ° C./min, and when the temperature reached 650 ° C., the heat treatment was performed for 10 minutes. Analysis of the metal composition in the middle part of the piezoelectric thin film revealed Pb _0.99 La _0.01 Zr _0.52 Ti _0.48 . The film thickness after coating and baking 10 times was 2.71 μm.

(Example 13)
The substrate was manufactured in the same manner as in Example 1 except that the substrate was changed from zirconia to Si wafer. (FIG. 5) The film thickness after three times of coating and baking was 1.22 μm.

(Comparative Examples 1-2)
Using the coating liquids obtained in Production Comparative Examples 1 and 2, piezoelectric elements were obtained in the same manner as in Examples 5 and 6.

[Evaluation]
Thirty piezoelectric elements of Examples 1 to 13 and Comparative Examples 1 and 2 were prepared and evaluated as follows.

  The amount of displacement when 10 kHz was applied between the upper electrode and the lower electrode at 10 V was measured by the laser Doppler method. Table 4 shows the results of the average value and the standard deviation of the initial displacement amount and the displacement amount after 720 hours of operation for each of the 30 elements.

  As can be seen from Table 4, it can be seen that the amount of displacement is larger than that of the comparative example, and that it is operating well after the 720 hour endurance test. In addition, an element with less non-uniform piezoelectric characteristics was obtained compared to the comparative example.

[Other evaluations]
The polarization characteristics with respect to the applied electric field in the piezoelectric elements manufactured in Example 1 and Comparative Example 1 were measured. In the measurement, a hysteresis curve was obtained by applying 20 V to the device using HVS-6000 manufactured by Radiants. This is shown in FIG.

  From this figure, it can be seen that Example 1 has a larger remanent polarization than Comparative Example 1. Since such a remarkable hysteresis characteristic can be a memory element, it can be used as a memory by arranging a plurality of voltages individually and applying a voltage individually. That is, it is possible to use as a rewritable memory by supplying a drive signal in accordance with information to be recorded, writing, detecting the polarization direction, and reading. When used as such a memory, the thickness of the piezoelectric thin film is preferably 0.1 μm to 2 μm.

  As described above, the piezoelectric element manufactured according to the present invention can be used not only for the piezoelectric element of the ink jet recording head but also for devices such as a memory, a capacitor, a sensor, and an optical modulator. 6 and 7 show an ink jet recording head to which a nozzle plate 10 provided with nozzles 6a is attached and an introduction path 11 for introducing ink is further provided. Good recording could be performed using such an ink jet recording head.

Sectional drawing which shows the outline of the piezoelectric material element of this invention. Sectional drawing which shows the outline at the time of setting the piezoelectric element of this invention as the actuator of an ink jet type printer head. The perspective view which shows the outline of the board | substrate used in Examples 1-13 and Comparative Examples 1-3. Sectional drawing which shows the outline of the board | substrate used in Examples 1-13 and Comparative Examples 1-3. Sectional drawing which shows the outline of the piezoelectric element produced in Examples 1-13 and Comparative Examples 1-3. Sectional drawing which shows the outline of the head used by evaluation of the ink jet type recording head. FIG. 3 is a perspective view showing an outline of a head used in the evaluation of an ink jet recording head. The hysteresis curve of Example 1 and the comparative example 1. FIG.

Claims (5)

  In a composition for forming a piezoelectric film containing a dispersoid obtained from a metal compound, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, , 4-diazabicyclo [2.2.2] octane at least one of them, and a piezoelectric film-forming composition.   2. The composition for forming a piezoelectric film according to claim 1, wherein the metal compound is an organometallic compound.   The at least one material is contained in an amount of not less than 0.005 times and not more than 5.0 times the number of moles of total metal atoms in the piezoelectric film composition. 3. The composition for forming a piezoelectric film according to 1 or 2.   4. The piezoelectric film forming composition according to claim 1, wherein the composition for forming a piezoelectric film includes at least one of Pb, La, Zr, and Ti as constituent elements. Composition. 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2.2] including dispersoids obtained from metal compounds Applying a piezoelectric film-forming composition containing at least one of octane to a substrate to form a coating film;
Drying the coating film;
Firing the dried coating film to obtain a piezoelectric film;
A method for producing a piezoelectric film, comprising:

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