JP2017069544A - Substrate for piezoelectric material film formation, manufacturing method thereof, piezoelectric material substrate, and liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for piezoelectric material film formation for supporting a piezoelectric material thin film which is high in piezoelectric material film's (100) plane orientation degree.SOLUTION: Used is a substrate for piezoelectric material film formation which comprises at least, an underlying base layer including SiOor SiN in its surface, an intermediate layer including at least one of Ti and TiO, on the underlying base layer, and an electrode layer including Pt on the intermediate layer. In the substrate, Ti is not detected on the surface of the electrode layer according to the element quantitative analysis. Otherwise, the substrate further comprises an orientation control layer including Pb, O and Ti as its constituent atoms on a stack of the underlying base layer, the intermediate layer, and the electrode layer; in the surface of the orientation control layer, of Pb, O and Ti elements, Ti accounts for 14.88 atom% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piezoelectric film forming substrate and a manufacturing method thereof, a piezoelectric substrate, and a liquid discharge head.

  In order to improve the adhesion between the base substrate and the lower electrode of the piezoelectric element in the piezoelectric film forming substrate, a layer structure having a Ti intermediate layer between the layers is often taken (see Patent Document 1).

In order to improve the piezoelectric characteristics of the piezoelectric element, it has been proposed to improve the degree of (100) orientation of the piezoelectric thin film, particularly PZT (lead zirconate titanate). Patent Document 2 discloses a layer structure having a 3% to 7 nm Ti nucleus 100% film between a lower electrode layer and a piezoelectric thin film layer. Further, Non-Patent Document 1 has a PbTiO ₃ layer for controlling orientation between the lower electrode layer and the piezoelectric thin film layer, and the piezoelectric layer has a composition with abundant PbO content (deficient in TiO ₂ content). The suggestion that (100) plane orientation predominates is disclosed. Regarding the PbTiO ₃ layer, also in Patent Document 1, a PbTiO ₃ layer raw material compound (precursor) is applied and dried as a base of PZT (lead zirconate titanate), and then a PZT raw material compound is applied and dried. Finally, firing is disclosed.

JP-A-10-126204 JP 2003-298136 A (Patent No. 3956134)

P. Muralt, J.M. Appl. Phys. 100, 051605 (2006)

Patent Document 2 and Non-Patent Document 1 disclose that a piezoelectric thin film having a high (100) orientation degree can be obtained. However, in Patent Document 2, a lower electrode having at least an Ir layer is formed on a ZrO ₂ film, and a 100% Ti nucleus film is formed thereon, which is different from the layer configuration provided in the present invention.

The formation of the PbTiO ₃ layer as in Patent Document 1 and Non-Patent Document 1 may ignore the configuration below the base electrode layer. However, when forming a piezoelectric thin film on a PbTiO ₃ layer formation condition, particularly on a PbTiO ₃ precursor as in Patent Document 1, even if the PbO amount suggested in Non-Patent Document 1 is abundant, The present inventors have found that the (100) orientation degree of the body thin film may not be sufficiently improved.

  The present invention has been made in view of the above problems. That is, the present invention provides a piezoelectric film forming substrate and a method for manufacturing the same, which can provide a piezoelectric element having a high (100) plane orientation ratio of the piezoelectric thin film and thus high piezoelectric characteristics. The present invention also provides a piezoelectric substrate using the piezoelectric film-forming substrate, and a liquid discharge head including a piezoelectric element including the piezoelectric substrate.

One embodiment is:
A base substrate layer containing at least SiO ₂ or SiN on the surface;
An intermediate layer including at least one of Ti and TiO ₂ on the base substrate layer, and an electrode layer including Pt on the intermediate layer;
The present invention relates to a piezoelectric film forming substrate, wherein the electrode layer has a thickness of 40 nm or more and 1000 nm or less, and Ti is not detected on the surface of the electrode layer by elemental quantitative analysis.

Other embodiments are:
A base substrate layer containing at least SiO ₂ or SiN on the surface;
An intermediate layer including at least one of Ti and TiO ₂ on the base substrate layer; an electrode layer including Pt on the intermediate layer;
An orientation control layer on the electrode layer,
The orientation control layer contains Pb, O, and Ti, and the Ti in the Pb, O, and Ti elements on the surface of the orientation control layer is 14.88 atomic% or less. About.

Other embodiments are:
A method for manufacturing a substrate for piezoelectric film formation,
Forming an intermediate layer containing at least one of Ti and TiO ₂ on a base substrate layer containing at least SiO ₂ or SiN on the surface;
Forming an electrode layer containing Pt on the intermediate layer;
Forming an orientation control layer containing Pb, O, Ti on the surface of the electrode,
The present invention relates to a manufacturing method characterized in that a temperature T (° C.) and a time t (minute) applied to the piezoelectric substrate during the step of forming the orientation control layer satisfy the following formula (1).

（但し ５０≦Ｔ≦４５０， ０＜ｔ＜３０ ）

(However, 50 ≦ T ≦ 450, 0 <t <30)

  By using the piezoelectric film formation substrate of the above embodiment, a piezoelectric substrate having a high (100) orientation ratio of the piezoelectric thin film and thus high piezoelectric characteristics can be provided. In addition, a liquid discharge head having excellent discharge droplet performance is provided by using this piezoelectric substrate.

It is a longitudinal cross-sectional schematic diagram which shows the piezoelectric material thin film of one Embodiment. It is a longitudinal cross-sectional schematic diagram which shows the piezoelectric material thin film of one Embodiment. FIG. 2 is a schematic perspective view illustrating a liquid discharge head according to an embodiment. It is a typical perspective sectional view showing a liquid discharge head of one embodiment. It is a typical sectional view showing a liquid discharge head of one embodiment. It is a figure which shows the X-ray-diffraction pattern in the position of (5) of the board | substrate in Example 1. FIG. It is a schematic diagram which shows the X-ray-diffraction measurement location on the board | substrate in an Example and a comparative example. (A) is a figure which shows the XPS spectrum with respect to the whole bond energy area | region in the Pt electrode surface of the piezoelectric material film-forming board | substrate of Example 1, (b) is an enlarged view which shows the Ti2p orbital area | region of this spectrum. It is a figure which shows the XPS spectrum with respect to the Ti2p orbital area | region in the Pt electrode surface of the piezoelectric material film-forming board | substrate of the comparative example 1. FIG. It is a figure which shows the (100) plane orientation degree of the PZT piezoelectric thin film laminated | stacked on it with respect to Ti amount ratio in the orientation control layer surface of the board | substrate for piezoelectric film formation.

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.
Here, a mechanism that causes high piezoelectric characteristics when the orientation ratio of the (100) plane of the piezoelectric thin film is high will be described. The crystal orientation of the piezoelectric thin film formed by the sol-gel method is such that the direction of the polarization moment increases as the orientation ratio of the (100) plane becomes higher than the orientation of other planes ((111) plane, (110) plane, etc.). Approaches the deformation direction of the piezoelectric body. Accordingly, the piezoelectric thin film having a larger orientation ratio of the (100) plane has a larger deformation amount and can be suitably used as an actuator such as a liquid discharge head.

1. Piezoelectric Film-Forming Substrate FIGS. 1 and 2 are schematic longitudinal sectional views of a piezoelectric film-forming substrate according to an embodiment. FIG. 1 shows a piezoelectric film forming substrate according to the first embodiment, which is composed of a laminate of a base substrate layer 1, an intermediate layer 2, and an electrode layer 3. 2 schematically illustrates a piezoelectric film-forming substrate according to the second embodiment in which the orientation control layer 4 is laminated on the piezoelectric film-forming substrate having the configuration shown in FIG.

The underlying substrate layer 1 includes at least SiO ₂ or SiN on the surface, but other materials are preferably materials that do not deform or melt in the heat treatment that can be performed in the formation process of each layer formed thereon. Further, it is preferable that the base substrate layer 1 has a smooth surface, can prevent diffusion of elements during heat treatment, and has sufficient mechanical strength. Moreover, when manufacturing a liquid discharge head using the piezoelectric substrate obtained by this embodiment, the base substrate layer 1 may also serve as a pressure chamber substrate for forming a pressure chamber. For example, for such purposes, the material of the base substrate layer 1 can be preferably a semiconductor substrate made of silicon (Si) or the like, or a metal substrate such as tungsten (W) or heat-resistant stainless steel (SUS), but zirconia or alumina. A ceramic substrate such as silica may be used. A plurality of these substrate materials may be combined, or may be laminated to form a multilayer structure. SiO ₂ or SiN is formed on the surface of these materials to form the base substrate layer 1. For example, the Si substrate can be oxidized or nitrided to modify the surface to a layer containing SiO ₂ or SiN.

The intermediate layer 2 is a layer inserted in order to improve the adhesion between the base substrate layer 1 and the electrode layer 3. For this reason, the material of the intermediate layer 2 includes at least one of Ti and TiO ₂ . A Ti layer and a TiO ₂ layer may be laminated. The intermediate layer 2 preferably has a layer thickness of 2 nm or more and 50 nm or less. This is because if the layer thickness of the intermediate layer 2 is 2 nm or more, a sufficient layer thickness for exhibiting adhesion can be secured, and if it is 50 nm or less, wasteful consumption of materials can be suppressed.

  The material of the electrode layer 3 may be any material that is usually used for a piezoelectric element containing Pt. For example, a Pt metal film or an oxide film containing Pt, Ti, Ta, Ir, Sr, In, Sn, Au, Metals such as Al, Fe, Cr, Ni, and oxides thereof may be included. The electrode layer 3 may be composed of a single layer or may be a laminate of two or more of these layers. These metals and oxides may be formed by applying and baking on a substrate by a sol-gel method or the like, or may be formed by sputtering or vapor deposition. Moreover, you may pattern and use it for a desired shape. The electrode layer 3 preferably has a layer thickness of 40 nm or more and 1000 nm or less. In the first embodiment, a sputtering method with a relatively small thermal history is suitable.

  Several atomic layers on the sputtered surface are disturbed by ions, and irradiation ions remain and amorphous layers are formed. Therefore, in order to remove and stabilize these, heat treatment may be performed after sputtering. This heat treatment may be performed in the sputtering apparatus or may be performed after being taken out from the sputtering apparatus.

  When a piezoelectric thin film was formed on a piezoelectric film forming substrate having such a layer structure, a phenomenon was observed in which the degree of orientation of the (100) plane of the piezoelectric thin film varied depending on the heat treatment conditions. Regarding this cause, when the surface state of the electrode film 3 on the piezoelectric film forming substrate before the piezoelectric thin film film formation was examined, when the presence of Ti on the electrode surface was confirmed, the degree of orientation decreased, It has been found that a high degree of orientation can be obtained when the presence is not confirmed. Conventionally, the detailed structure with respect to Ti of the piezoelectric film-forming substrate in which the (100) plane orientation degree of the piezoelectric thin film is high has not been elucidated.

Therefore, the piezoelectric film formation substrate according to the first embodiment of the present invention includes a base substrate layer containing at least SiO ₂ or SiN on the surface and an intermediate containing at least one of Ti and TiO ₂ on the base substrate layer. And an electrode layer containing Pt on the intermediate layer, and Ti is not detected on the surface of the electrode layer by elemental quantitative analysis.

  In order to suppress Ti migration (migration) from the Ti layer, it is known to passivate the surface of the Ti layer. However, Ti migration occurs slightly depending on the temperature and time of the heat treatment after Pt sputtering. Therefore, in the present embodiment, conditions for suppressing Ti migration are selected by controlling the temperature and time of heat treatment at the time of electrode layer formation and after electrode layer formation. Selection of such heat treatment conditions can be performed experimentally. For example, the heat treatment after sputtering when the electrode layer is formed by sputtering is preferably a temperature of 280 ° C. or lower. Further, in order to achieve the purpose of heat treatment after sputtering such as removal of residual irradiation ions and crystallization, the temperature is preferably 100 ° C. or higher, and more preferably 150 ° C. or higher. Moreover, although heat processing time changes with temperature conditions, 5 minutes or less are preferable and the objective of the heat processing after sputtering can be achieved even if it is about 1 minute.

  The orientation control layer 4 is a layer that controls the orientation of the piezoelectric thin film layer laminated thereon, and includes Pb, O, and Ti as constituent atoms. The material of the orientation control layer 4 is not particularly limited, but it is preferable that an organometallic oxide containing at least Pb and / or Ti is included. In particular, a composite organometallic oxide of Pb and Ti is more preferable. The orientation control layer 4 also has an effect of suppressing diffusion of Pb to the lower part due to a temperature load during film formation when lead zirconate titanate (PZT) is laminated as a piezoelectric thin film on the upper part. Further, it has an effect of suppressing diffusion of Ti in the lower intermediate layer into the upper piezoelectric thin film layer due to temperature load.

  Examples of the method for manufacturing the orientation control layer 4 include metal organic chemical vapor deposition (MOCVD (Metal Organic Chemical Vapor Deposition) method), sol-gel method, and the like. Among them, the sol-gel method is preferable because it is the cheapest and can easily form an orientation control layer. In the sol-gel method, first, a coating solution containing a hydrolyzable compound of each component metal as a raw material, a partially hydrolyzable compound thereof, or a partially polycondensable compound thereof (orientation control layer material) is prepared. The prepared coating solution is applied onto a substrate, and the coating solution is dried to form.

  Examples of the raw material for generating the orientation control layer material include an organometallic compound. For example, metal complexes such as lead or titanium alkoxides, organic acid salts, and β-diketone complexes are typical examples. Regarding the metal complex, various other complexes including amine complexes can be used. Examples of the β-diketone for forming the β-diketone complex include acetylacetone (= 2,4-pentanedione), heptafluorobutanoylpivaloylmethane (= 1- (heptafluoropropyl) -4,4-dimethyl- 1,3-pentanedione), dipivaloylmethane (= 2,2,6,6-tetramethyl-3,5-heptanedione), trifluoroacetylacetone, benzoylacetone and the like.

  Examples of the lead compound include organic acid salts such as lead acetate and organometallic alkoxides such as diisopropoxy lead. The titanium compound is preferably an organometallic alkoxide such as tetraethoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium, tetratert-butoxytitanium, dimethoxydiisopropoxytitanium, etc. Metal complexes can also be used.

  The coating liquid is a precursor of lead titanate, which is an orientation control layer material, by dissolving or dispersing each of the raw material organometallic compounds as described above in an appropriate organic solvent, for example, heat treatment, and further hydrolysis. A compound, such as one containing a complex organometallic oxide of Pb and Ti, is prepared. The composite organometallic oxide includes an organic substance containing Pb and an organic substance containing Ti. As for the ratio of Pb and Ti in the orientation control layer material, Pb / Ti is preferably 1/1 or higher and 1.8 / 1 or lower, and more preferably 1.2 / 1 or higher and 1.5 / 1 or lower.

  Moreover, the organic solvent used for the preparation of the coating liquid is appropriately selected from known various solvents in consideration of dispersibility and coatability. Examples of the organic solvent used for preparing the coating solution include alcohol solvents such as methanol, ethanol, n-butanol, n-propanol, and isopropanol, ether solvents such as tetrahydrofuran and 1,4-dioxane, methyl cellosolve, ethyl cellosolve, and the like. Amide solvents such as cellosolve, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methylpyrrolidone, and nitrile solvents such as acetonitrile. Among these, it is preferable to use an alcohol solvent.

  The amount of the organic solvent in the coating liquid is not particularly limited, but it is preferable to adjust the amount of the organic solvent so that the metal solid content concentration is 15% by mass or more and 30% by mass or less.

  As a coating method of the coating liquid, a known coating method such as spin coating, dip coating, bar coating, spray coating, or the like can be used. Moreover, when coating a coating liquid on a board | substrate, it is preferable that the surface which coats the coating liquid of a board | substrate is arrange | positioned in the horizontal direction (direction orthogonal to a perpendicular direction). Thereby, a coating layer having a uniform film thickness and a uniform distribution of the orientation control layer material can be obtained. The coating solution may be applied only once or a plurality of times.

  In the drying step after the coating layer forming step, the organic solvent is evaporated from the coating layer in a windless environment to obtain an orientation control layer. This step may be any drying temperature suitable for the organic solvent to be used, and is usually a temperature of 50 ° C. or higher, and is preferably performed at a temperature of 100 ° C. or higher. The drying temperature is 450 ° C. or lower, and preferably 300 ° C. or lower. The drying time is preferably less than 30 minutes. In particular, in the present embodiment, the process is performed under a condition that satisfies a formula (1) described later. This step is performed by placing the substrate in a heat source such as a dryer, hot plate, tubular furnace, electric furnace, or by directly contacting the substrate with a heat source such as a dryer, hot plate, tubular furnace, electric furnace or the like. Can do. Among these, the hot plate heated from the back surface of a board | substrate is preferable from the point of the uniformity of heating temperature.

  The formation process of the orientation control layer (dry coating layer) is performed so that the surface (coating surface) coated with the coating liquid of the substrate is in a windless environment. Specifically, an air supply port for supplying warm air or hot air or an exhaust port for exhausting air is not provided on the coating surface. Further, when the air supply port and the exhaust port are provided, the flow of the organic solvent vaporized or hot air on the substrate is prevented. As a result, the gas flow rate is set to 0.05 m / s or less at a position of 20 cm on the surface of the substrate coated with the coating liquid.

  The film thickness of the orientation control layer 4 after drying in this way is preferably 10 nm or more and 100 nm or less. If it is 10 nm or more, the effect of controlling the orientation and the effect of suppressing diffusion are sufficiently obtained, and if it is 100 nm or less, the characteristics of the piezoelectric thin film are not adversely affected.

  According to the study by the present inventors, the surface state of the orientation control layer changes depending on the drying conditions for forming the orientation control layer, and even if a raw material having the same composition ratio is used, It has been found that the degree of orientation of the (100) plane changes. In particular, it has been found that when the Ti in the Pb, O, and Ti elements on the surface of the orientation control layer is 14.88 atomic% or less, a high degree of orientation of the (100) plane of the piezoelectric thin film can be obtained. The Ti element ratio on the surface of the orientation control layer is more preferably 14.8 atomic% or less.

Therefore, the piezoelectric film-forming substrate according to the second embodiment of the present invention includes a base substrate layer containing at least SiO ₂ or SiN on the surface, and an intermediate containing at least one of Ti and TiO ₂ on the base substrate layer. A layer, an electrode layer containing Pt on the intermediate layer, and an orientation control layer on the electrode layer, the orientation control layer containing Pb, O and Ti, and Pb on the surface of the orientation control layer , O, Ti in Ti element is 14.88 atomic% or less.

The method for manufacturing a piezoelectric film-forming substrate according to the _second embodiment includes a step of forming an intermediate layer including at least one of Ti and TiO ₂ on a base substrate layer including at least SiO ₂ or SiN on the surface. And at least a step of forming an electrode layer containing Pt on the intermediate layer and a step of forming an orientation control layer containing Pb and Ti on the surface of the electrode. The present invention relates to a manufacturing method characterized in that a temperature T (° C.) and a time t (minute) applied to a body substrate satisfy the following formula (1).

（但し ５０≦Ｔ≦４５０， ０＜ｔ＜３０ ）
上記式（１）を満足することで配向制御層の表面におけるＰｂ、Ｏ、Ｔｉ元素中の該Ｔｉを１４．８８原子％以下とすることができる。

(However, 50 ≦ T ≦ 450, 0 <t <30)
By satisfying the above formula (1), the Ti in the Pb, O and Ti elements on the surface of the orientation control layer can be reduced to 14.88 atomic% or less.

2. Piezoelectric Substrate Next, a piezoelectric substrate according to a third embodiment of the present invention will be described. The piezoelectric substrate of this embodiment is obtained by forming a piezoelectric thin film on the electrode layer 3 shown in FIG. 1 or the orientation control layer 4 shown in FIG. The orientation control layer becomes lead titanate when the piezoelectric thin film is fired, and functions as a part of the piezoelectric thin film. The piezoelectric substrate is provided with an electrode (also referred to as an upper electrode) facing the electrode layer 3 (also referred to as a lower electrode) via a piezoelectric thin film. Piezoelectric elements are elements that convert the force applied to the piezoelectric body due to the piezoelectric effect into voltage, or elements that convert voltage into force, but in the present invention, they are used as elements (actuators) that convert voltage into force. Is preferred. The upper electrode may be formed on the entire surface of the piezoelectric thin film or a part thereof. The upper electrode may be formed integrally with the piezoelectric substrate, or may be detachable. The material of the upper electrode can be used without particular limitation as long as it is a conductive material that can apply a voltage to the piezoelectric thin film, and the same material as the material of the lower electrode can be used.
Moreover, each wiring layer to the upper and lower electrodes of the piezoelectric element may be formed on the piezoelectric substrate. For example, each wiring layer can be formed in the same layer as the lower electrode by using a lower electrode material. . In this case, the upper electrode can be connected to the wiring layer through a through hole, a lead electrode, or the like.

The material of the piezoelectric thin film is not particularly limited, but preferably includes lead zirconate titanate (PZT). PZT is preferably a perovskite crystal represented by the general formula Pb _{(1.00 to 1.20)} (Zr _x Ti _1-x ) O ₃ (x is 0.4 to 0.6). By setting the composition of Zr and Ti within the above range, a perovskite crystal having high piezoelectricity can be obtained.
Note that a trace amount of elements other than Pb, Zr, and Ti may be doped in the piezoelectric thin film. Specific examples of elements that can be used as dopants when doping include La, Ca, Sr, Ba, Sn, Th, Y, Sm, Ce, Bi, Sb, Nb, Ta, W, Mo, Cr , Co, Ni, Fe, Cu, Si, Ge, Sc, Mg, and Mn. Addition _{amount, Pb (1.00~1.20) (Zr x} Ti 1-x) O 3 2 wt% 0.1 wt% (x is 0.4-0.6) are preferred.

Examples of the method for manufacturing the piezoelectric thin film include a sputtering method, a metal organic chemical vapor deposition method (MOCVD (Metal Organic Chemical Vapor Deposition) method), and a sol-gel method. Of these, the sol-gel method is preferred because it is the cheapest and can easily form a piezoelectric thin film. In the sol-gel method, first, a coating liquid containing a hydrolyzable compound of each component metal as a raw material, a partially hydrolyzable compound thereof, or a partially polycondensable compound thereof (piezoelectric precursor) is prepared. As the doping element, a compound containing these elements may be added at the time of preparing the coating solution. The prepared coating liquid is applied onto a substrate, and the coating liquid is dried to form a coating layer. Thereafter, the coating layer is heated in air, and further baked at a temperature equal to or higher than the crystallization temperature to be crystallized, thereby forming a piezoelectric thin film.
As a method similar to the sol-gel method, there is an organometallic decomposition method (MOD (Metal Organic Deposition) method). In the MOD method, a coating liquid containing a thermally decomposable organometallic compound (metal complex and metal organic acid salt), for example, a metal β-diketone complex or a carboxylate, is applied on the substrate as a piezoelectric precursor. Work. Next, for example, the coating liquid is heated in the air or in oxygen to cause evaporation of the solvent in the coating liquid and thermal decomposition of the organometallic compound, and further, by calcination at a temperature equal to or higher than the crystallization temperature. In this method, a piezoelectric thin film is formed.
In the present specification, the above-described sol-gel method, MOD method, and a combination thereof are collectively referred to as “sol-gel method”.

3. Next, a method for manufacturing a piezoelectric thin film according to the present embodiment will be described. The manufacturing method of this embodiment has the formation process of a coating layer, the formation process of a dry coating layer, and the heating process of a dry coating layer. Hereinafter, each step will be described.
In the present specification, the “coating layer” refers to a layer composed of a coating solution coated on a substrate before the organic solvent evaporates. The “dry coating layer” represents the coating layer after the organic solvent has evaporated.

(1) Coating layer forming step In the coating layer forming step, a coating liquid containing an organic solvent and a piezoelectric precursor is applied onto the piezoelectric thin film forming substrate. Thus, the board | substrate with which the coating layer containing an organic solvent and a piezoelectric material precursor was formed is prepared. Examples of the piezoelectric precursor include hydrolyzable compounds of respective component metals, partially hydrolyzable compounds thereof, partially polycondensable compounds, thermally decomposable compounds, or raw materials for these compounds. Examples of raw materials for producing these compounds include organometallic compounds. For example, metal complexes such as the above metal alkoxides, organic acid salts, and β-diketone complexes are typical examples. Regarding the metal complex, various other complexes including amine complexes can be used. Examples of the β-diketone for forming the β-diketone complex include acetylacetone (= 2,4-pentanedione), heptafluorobutanoylpivaloylmethane (= 1- (heptafluoropropyl) -4,4-dimethyl- 1,3-pentanedione), dipivaloylmethane (= 2,2,6,6-tetramethyl-3,5-heptanedione), trifluoroacetylacetone, benzoylacetone and the like.

  Specific examples of organometallic compounds suitable as raw materials include organic acid salts such as lead acetate and organometallic alkoxides such as diisopropoxy lead as lead compounds. The titanium compound is preferably an organometallic alkoxide such as tetraethoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium, tetratert-butoxytitanium, dimethoxydiisopropoxytitanium, etc. Metal complexes can also be used. As for the zirconium compound, zirconium organometallic alkoxides, organic acid salts, and organometallic complexes can be used in the same manner as the lead compounds and titanium compounds. Although the same thing as the above can be used also about another metal compound, it is not limited to these. Further, the above metal compounds may be used in combination. The 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.

  The coating liquid is prepared by dissolving or dispersing each of the raw material organometallic compounds as described above in a suitable organic solvent, for example, heat-treating, and further hydrolyzing to form a composite organometallic oxide (piezoelectric precursor) ( Containing two or more component metals).

Moreover, the organic solvent used for the preparation of the coating liquid is appropriately selected from known various solvents in consideration of dispersibility and coatability. Examples of the organic solvent used for preparing the coating solution include alcohol solvents such as methanol, ethanol, n-butanol, n-propanol, and isopropanol, ether solvents such as tetrahydrofuran and 1,4-dioxane, methyl cellosolve, ethyl cellosolve, and the like. Amide solvents such as cellosolve, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methylpyrrolidone, and nitrile solvents such as acetonitrile. Among these, it is preferable to use an alcohol solvent.
The amount of the organic solvent in the coating liquid is not particularly limited, but it is preferable to adjust the amount of the organic solvent so that the metal solid content concentration is 15% by mass or more and 30% by mass or less. When the amount of the organic solvent in the coating liquid is within these ranges, the layer thickness of the piezoelectric thin film in one coating can be easily set to 150 nm or more and 400 nm or less.

In the case of using a plurality of organometallic compounds, the ratio of each organometallic compound in the coating liquid is the material of the piezoelectric thin film to be manufactured, for example, Pb _(1.00-1.20) (Zr _x Ti _{1- It} is preferable that the composition ratio is approximately the same as the composition ratio of _x ) O ₃ (x is 0.4 to 0.6). In _the case of forming a piezoelectric thin film made of _{Pb (1.00~1.20) (Zr x Ti} 1-x) O 3 (x is 0.4-0.6), generally lead compounds volatile High, lead deficiency may occur due to evaporation during the heat treatment process described later. Therefore, in anticipation of this deficiency, lead may be present in a slightly excessive amount, for example, 2 mol% or more and 40 mol% or less in excess of the required amount of lead in terms of composition ratio. The degree of lead deficiency varies depending on the type of lead compound and the film forming conditions, and can be determined by experiment.

  In the coating solution, 1,8-diazabicyclo [5.4.0] -7-undecene (hereinafter sometimes referred to as “DBU”), 1,5-diazabicyclo [4.3 as stabilizers. 0.0] non-5-ene (hereinafter sometimes referred to as “DBN”), 1,4-diazabicyclo [2.2.2] octane (hereinafter sometimes referred to as “DABCO”). Further, β-diketones (for example, acetylacetone, heptafluorobutanoylpivaloylmethane, dipivaloylmethane, trifluoroacetylacetone, benzoylacetone, etc.), ketonic acids, which have been conventionally used as other stabilizers (For example, acetoacetic acid, propionylacetic acid, benzoylacetic acid, etc.), lower alkyl esters of these ketone acids such as ethyl, propyl, butyl, etc., oxyacids (for example, lactic acid, glycolic acid, α-oxybutyric acid, salicylic acid, etc.), Lower alkyl esters of these oxyacids, oxyketones (eg, diacetone alcohol, acetoin, etc.), α-amino acids (eg, glycine, alanine, etc.), alkanolamines (eg, diethanolamine, triethanolamine, monoethanol) Amine) etc. It may be use.

  The amount of the stabilizer in the coating solution is preferably 0.05 to 5 times the total moles of metal atoms, preferably 0.1 to 1.5 times the mole. More preferably.

In the coating process, for example, a coating solution is applied onto the electrode of a substrate having an electrode on the surface. As a coating method of the coating liquid, a known coating method such as spin coating, dip coating, bar coating, spray coating, or the like can be used. Moreover, when coating a coating liquid on a board | substrate, it is preferable that the surface which coats the coating liquid of a board | substrate is arrange | positioned in the horizontal direction (direction orthogonal to a perpendicular direction). Thereby, a coating layer having a uniform film thickness and a uniform distribution of the piezoelectric precursor can be obtained. The coating solution may be applied only once or a plurality of times.
The film thickness of the piezoelectric thin film (piezoelectric thin film after manufacture) obtained by applying the coating liquid once is not particularly limited, but is preferably 150 nm or more and 400 nm or less. When the film thickness of the piezoelectric thin film is 150 nm or more, a piezoelectric thin film having excellent piezoelectric characteristics can be manufactured with a small number of coatings. Moreover, when the film thickness of the piezoelectric thin film is 400 nm or less, epitaxial crystal growth in the layer thickness direction can be effectively performed.

  The film thickness of the piezoelectric thin film can be controlled by changing the concentration of the piezoelectric precursor in the coating liquid and the coating conditions, and these conditions can be obtained by experiments. For example, a coating liquid having a solid content concentration of 20% by mass or more and 25% by mass or less is applied by spin coating at 2000 rpm, and the coating liquid is dried and the piezoelectric precursor is heat-treated. Thereby, a piezoelectric thin film having a thickness of 200 nm or more and 330 nm or less can be formed for each coating. The film thickness of the finally formed piezoelectric body (including the orientation control layer) is preferably 4 μm or less.

(2) Dry coating layer forming step In the dry coating layer forming step after the coating layer forming step, the organic solvent is evaporated from the coating layer in a windless environment to dry the piezoelectric precursor. A coating layer is obtained. This step may be any drying temperature suitable for the organic solvent to be used, and is usually a temperature of 50 ° C. or higher, preferably 100 ° C. or higher and 450 ° C. or lower. This step is performed by placing the substrate in a heat source such as a dryer, hot plate, tubular furnace, electric furnace, or by directly contacting the substrate with a heat source such as a dryer, hot plate, tubular furnace, electric furnace or the like. Can do. Among these, the hot plate heated from the back surface of a board | substrate is preferable from the point of the uniformity of heating temperature.
The formation process of the dry coating layer is performed so that the surface (coated surface) coated with the coating liquid of the substrate is in a windless environment. Specifically, an air supply port for supplying warm air or hot air or an exhaust port for exhausting air is not provided on the coating surface. In addition, when the air supply port and the exhaust port are provided, the flow of the organic solvent or hot air is prevented from occurring on the substrate. As a result, the gas flow rate is set to 0.05 m / s or less at a position of 20 cm on the surface of the substrate coated with the coating liquid.

(3) Drying coating layer heating step After the drying coating layer is formed, in the drying coating layer heating step, the drying coating layer is heated to convert the piezoelectric precursor from the piezoelectric precursor contained in the drying coating layer. The thin film is formed. This step can be performed by placing the substrate in a heat source such as a dryer, hot plate, tubular furnace, electric furnace, or bringing these heat sources into contact with the substrate. At this time, the heating is preferably performed at 500 ° C. or higher and 800 ° C. or lower. The heating process of the dry coating layer may be performed in a plurality of times or only once. Preferably, the piezoelectric thin film is formed by heating the dried coating layer by temporary baking and further baking and crystallizing at a temperature higher than the crystallization temperature.

4). Piezoelectric thin film manufacturing apparatus The piezoelectric thin film manufacturing apparatus includes a coating unit, a drying unit, and a heating unit. The coating means can apply a coating liquid containing an organic solvent and a piezoelectric precursor on the substrate to form a coating layer. The substrate is placed on the placement unit. The drying means can evaporate the organic solvent from the coating layer in a windless environment to obtain a dry coating layer containing the piezoelectric precursor. The heating means can heat the dry coating layer to form a piezoelectric thin film from the piezoelectric precursor contained in the dry coating layer.

5. Orientation Evaluation Method Next, a method for evaluating the orientation of the (100) plane of the piezoelectric thin film will be described. The orientation state of the (100) plane of the piezoelectric thin film can be easily confirmed from the detection angle and intensity of the diffraction peak in the X-ray diffraction measurement by the 2θ / θ method, which is generally used for the crystal thin film and uses Cu Kα ray as the wavelength. . For example, as shown in FIG. 6, in the diffraction chart obtained from the piezoelectric thin film of this embodiment, the (100) plane has a peak intensity around 22 °, the (110) plane near 31 °, The (111) plane has a peak intensity around 38 °. By dividing the peak intensity of the (100) plane by the sum of the peak intensities of the (100) plane, the (110) plane, and the (111) plane, the intensity ratio of the (100) plane can be obtained.
Since good piezoelectricity can be obtained, the ratio of the intensity of the (100) plane to the sum of the peak intensity of the (100) plane, the (110) plane, and the (111) plane is 80% or more in each part of the substrate. Preferably, 90% or more is more preferable. The main surface of the substrate and the (100) surface of the piezoelectric thin film are preferably parallel to each other.

6). Elemental Quantitative Analysis Next, an elemental quantitative analysis method on the thin film surface will be described. In the present invention, an Auranta SXM X-ray photoelectron spectroscopy (XPS) analyzer manufactured by ULVAC-PHI Co., Ltd. is used, and analysis software (MultiPak Version 9.3.0.3) is used. The element amount (atomic%) is calculated using the relative sensitivity coefficient method described.
(Measurement condition)
X-ray source: Monochromatic AlKα
X-ray output: 25W15kV
X-ray beam diameter: 100 μm
Photoelectron extraction angle: 45 °
The element quantitative analysis method on the surface of the thin film is not limited to XPS. In addition to XPS, an analysis method such as fluorescent X-ray (XRF) analysis or high-frequency glow discharge emission surface analysis (GDS) can be used. .

  In the present specification, “the Ti is not detected by the elemental quantitative analysis method” means that, for example, the Ti2p peak is not detected in a region where the binding energy is 450 nm or more and less than 470 nm by XPS. In addition, “the Ti in the Pb, O, and Ti elements on the surface of the orientation control layer is 14.88 atomic% or less” means, for example, that the element amount of Ti obtained by elemental quantitative analysis by XPS is Pb, It means that the value divided by the sum of the element amounts of O and Ti is 14.88% or less. Here, the elemental amount of Ti on the surface of the orientation control layer is calculated from a spectrum corresponding to the XPS Ti2p orbital, the elemental amount of Pb is calculated from the spectrum corresponding to the Pb4f orbital, and the elemental amount of O is calculated from the spectrum corresponding to the O1s orbital. I can do it.

7). Liquid Discharge Head FIGS. 3 to 5 show a liquid discharge head according to an embodiment using a piezoelectric substrate. The liquid discharge head M includes a liquid discharge head substrate 21, a plurality of liquid discharge ports 22, a plurality of pressure chambers 23, and an actuator 25 disposed so as to correspond to each pressure chamber 23. ing. Each pressure chamber 23 is provided corresponding to each liquid discharge port 22 and communicates with the liquid discharge port 22. The actuator 25 causes the ink volume in the pressure chamber 23 to change due to the vibration, and ejects droplets such as ink from the liquid ejection port 22. The liquid discharge ports 22 are formed in the nozzle plate 24 with a predetermined interval, and the pressure chambers 23 are formed in parallel on the liquid discharge head substrate 21 so as to correspond to the liquid discharge ports 22 respectively. In the present embodiment, the liquid discharge port 22 is provided on the surface facing the pressure generation surface by the actuator 25, but may be provided on a surface other than the surface facing the pressure generation surface by the actuator 25. Each actuator 25 includes a diaphragm 26 and a piezoelectric element 30, and the piezoelectric element 30 includes a piezoelectric thin film 27 and a pair of electrodes (a lower electrode 28 and an upper electrode 29). Openings 21A corresponding to the respective pressure chambers 23 are formed on the upper surface of the liquid discharge head substrate 21, and the actuators 25 are arranged so as to close the openings. FIG. 5 shows a configuration in which the diaphragm 26 is exposed at the opening. However, if the liquid in the pressure chamber 23 can be discharged from the liquid discharge port 22 by the vibration generated by the actuator 25, the discharge liquid discharge head is used. A part of the substrate 21 may remain. 3 shows a state in which the nozzle plate 24 is separated and developed from the liquid discharge head substrate 21 for the sake of explanation. Actually, the nozzle plate 24 is placed on the liquid discharge head substrate 21 as shown in FIG. It is joined.
The material of the diaphragm 26 is not particularly limited, but a semiconductor such as Si exemplified as the material of the base substrate layer, metal, metal oxide, glass, or the like is preferable. The liquid discharge head substrate 21 and the vibration plate 26 may be formed by bonding or adhesion, or the vibration plate 26 may be directly formed on the liquid discharge head substrate 21. Further, the lower electrode 28 and the piezoelectric thin film 30 may be formed directly on the liquid discharge head substrate 21 without providing the diaphragm 26. In that case,

In the actuator to which the present invention is applied, the diaphragm 26 corresponds to a base substrate, the base substrate layer 2 containing SiO ₂ or SiN is formed on the surface, and the intermediate layer 3 is formed on the base substrate layer. When the intermediate layer has conductivity, a part of the lower electrode 28 is formed. Further, when the orientation control layer is formed on the lower electrode and the piezoelectric thin film is formed thereon, the orientation control layer is also baked at the final stage of the piezoelectric thin film formation to constitute a part of the piezoelectric thin film. Become.

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

(Production of lead zirconate titanate (PZT) coating solution)
As a coating liquid for forming a piezoelectric thin film, a PZT coating liquid having a metal composition represented by Pb / Zr / Ti = 1.2 / 0.52 / 0.48 was prepared as follows.
1.2 mol of lead acetate hydrate was dehydrated by heating, and 1.2 mol of 1,8-diazabicyclo [5.4.0] -7-undecene and 1-methoxy-2-propanol (9. 0 mol) is mixed and reacted by heating and stirring. Thereafter, 0.52 mol of tetra-n-butoxyzirconium and 0.48 mol of tetraisopropoxytitanium were added and further heated and reacted to complex the metal compounds with each other. Next, water (5.0 mol) and ethanol (5.0 mol) were added and a hydrolysis reaction was performed to obtain a piezoelectric precursor made of an organometallic oxide. At that time, acetic acid (3.8 mol) and acetylacetone (0.6 mol) were added. Thereafter, the solvent with a boiling point of 100 ° C. or less is completely removed with a rotary evaporator, and diethylene glycol monoethyl ether (organic solvent) is added to adjust the concentration so that the concentration of the metal oxide converted to the above composition formula becomes 23% by mass. A PZT coating solution was prepared.

[Example 1]
A silica (SiO ₂ ) layer having a thickness of 500 nm is provided as a base substrate layer 1 by thermal oxidation on the surface of a silicon substrate having a diameter of 6 inches (15 cm). Further, by sputtering, Ti is 50 nm as an intermediate layer 2 and Pt is 200 nm as an electrode layer 3. And formed into a piezoelectric film forming substrate used in this example (see FIG. 1). As annealing after sputtering, heat treatment was performed by the following method.
The above piezoelectric film-forming substrate is placed on a hot plate heated to 150 ° C. (“Shamal Hot Plate HHP-411” manufactured by As One Co., Ltd., temperature unevenness of the board surface is 150 ° C. ± 1 ° C.) for 1 minute, and the substrate Was heated. At this time, the hot plate was installed in a windless environment (wind speed 0 m / s) (measured at a position 2 cm above the substrate; an anemometer DT-8880 manufactured by CEM was used), and no shielding plate or the like was provided.

[Example 2, Comparative Examples 1-3]
In Example 1, a piezoelectric film-forming substrate was produced in the same process except that the surface temperature of the hot plate and the heating time were changed to the conditions shown in Table 1.

  The piezoelectric film-forming substrates prepared in Examples 1-2 and Comparative Examples 1-3 were evaluated as follows. The piezoelectric film formation substrate was divided into nine pieces as shown in FIG. 7, and when detecting and detecting Ti on the surface of the Pt electrode of each piezoelectric film formation substrate, the quantitative ratio was measured by XPS analysis. . Here, the Ti amount ratio is calculated by dividing the atomic% calculated from the peak corresponding to the Ti2p orbit by the sum of the atomic% calculated from the peak corresponding to the Pt4f orbit and the atomic% calculated from the peak corresponding to the Ti2p orbital. Yes, it is the value of the average of three measurements of XPS. In FIG. 7, (5) is a portion from the center of the substrate to a radius of 3 cm, (1), (2), (3), (4), (6), (7), (8), (9) are A portion having a radius of 3 cm or more and 6 cm or less from the center of the substrate was measured. The results are shown in Table 1. Further, FIG. 8A shows the XPS spectrum in the entire binding energy region of Example 1, and FIG. 8B shows the XPS spectrum of only the Ti2p region (450 nm to 470 nm) where the Ti2p peak was not detected. Furthermore, FIG. 9 shows an XPS spectrum in which the Ti2p peak of the piezoelectric film-forming substrate produced in Comparative Example 1 was detected.

Next, the PZT coating solution prepared as described above was applied to the Pt surface of the substrate using a spin coater (4000 rpm for 15 seconds) (coating layer forming step). Next, a hot plate heated to 280 ° C. (“Shamal Hot Plate HHP-411” manufactured by AS ONE Co., Ltd., temperature unevenness on the panel surface was 280 ° C. ± 1 ° C.) was prepared. A substrate coated with the PZT coating solution was placed on the hot plate for 5 minutes, and the organic solvent in the PZT coating solution was evaporated (dry coating layer forming step). At this time, the hot plate was installed in a windless environment (wind speed 0 m / s) (measured at a position 2 cm above the substrate; an anemometer DT-8880 manufactured by CEM was used), and no shielding plate or the like was provided. The piezoelectric film-forming substrate was placed in an electric furnace at 650 ° C. for 10 minutes, and the piezoelectric precursor was a piezoelectric thin film made of Pb _1.2 (Zr _0.52 Ti _0.48 ) O ₃ . The heat treatment step for 10 minutes in the electric furnace at 650 ° C. corresponds to the heating step for the dry coating layer. Thereafter, X-ray diffraction (2θ / θ method) of each piezoelectric thin film was measured with an X-ray diffractometer (RINT2100 manufactured by Rigaku Corporation). FIG. 6 shows the X-ray diffraction pattern of (5) of Example 1, and the peak seen in the vicinity of 40 ° is the peak of the (111) plane of Pt provided on the substrate.

  From FIG. 6, the peak intensity value of the (100) plane of the piezoelectric thin film is divided by the sum of the peak intensity values of the (100) plane, the (110) plane, and the (111) plane. (Orientation degree). The peak of the (200) plane seen near 44 ° is a crystal plane equivalent to the (100) plane and is not included in the ratio of the intensity of the (100) plane. Table 1 shows the degree of orientation in the (100) plane of Examples 1 and 2 and Comparative Examples 1 to 3.

  As shown in Table 1, it was revealed that when Ti is not detected on the Pt electrode, a high (100) plane orientation degree of 90% or more can be obtained. In particular, it is possible to form a piezoelectric thin film having a high (100) plane orientation without forming a layer for controlling the orientation of the piezoelectric thin film.

[Example 3]
(Manufacture of orientation control layer coating solution)
A coating solution for the orientation control layer having a metal composition represented by Pb / Ti = 1.2 / 1.0 was prepared as follows.
1.2 mol of lead acetate hydrate was dehydrated by heating, and 1.2 mol of 1,8-diazabicyclo [5.4.0] -7-undecene and 1-methoxy-2-propanol (9. 0 mol) is mixed and reacted by heating and stirring. Thereafter, 1.0 mol of tetraisopropoxytitanium was added and the mixture was further heated and reacted to complex the metal compounds with each other. Next, water (5.0 mol) and ethanol (5.0 mol) were added and a hydrolysis reaction was performed to obtain an alignment control layer material made of an organometallic oxide. At that time, acetic acid (3.8 mol) and acetylacetone (0.6 mol) were added. Thereafter, the solvent having a boiling point of 100 ° C. or less is removed with a rotary evaporator, and diethylene glycol monoethyl ether (organic solvent) is added, so that the concentration in terms of lead titanate having the above metal composition is 1.0% by mass. Was adjusted to prepare a coating solution for the orientation control layer.

  The orientation control layer coating solution prepared as described above was applied to the Pt surface of the piezoelectric film-forming substrate for 15 seconds by a spin coater (2000 rpm) (coating layer forming step). Next, a hot plate heated to 130 ° C. (“Shamal Hot Plate HHP-411” manufactured by As One Co., Ltd., temperature unevenness on the panel surface was 130 ° C. ± 1 ° C.) was prepared. A substrate coated with the coating solution was placed on the hot plate for 1 minute to evaporate the organic solvent in the coating solution (dry coating layer forming step). At this time, the hot plate was installed in a windless environment (wind speed 0 m / s) (measured at a position 2 cm above the substrate; an anemometer DT-8880 manufactured by CEM was used), and no shielding plate or the like was provided.

[Examples 4 to 11, Comparative Examples 4 to 9]
In Example 3, a piezoelectric film-forming substrate was produced in the same process except that the formation process of the dry coating layer was set to the drying temperature and the drying time shown in Table 2.

  The piezoelectric film-forming substrates prepared in Examples 3 to 11 and Comparative Examples 4 to 9 were evaluated as follows. The piezoelectric film-forming substrate was divided into nine pieces as shown in FIG. 7, and the Ti amount ratio of each orientation control layer surface was measured using XPS. Here, the Ti amount ratio (atomic%) is the element amount calculated from the peak corresponding to the Ti2p orbital, the element amount calculated from the peak corresponding to the Pb4f orbital, the element amount calculated from the peak corresponding to the Ti2p orbital, and the O1s orbital. It can be calculated by dividing by the sum of the element amounts calculated from the corresponding peak, and is an XPS triplicate average value. The results are shown in Table 2.

  Next, the PZT coating solution prepared as described above on the surface of each orientation control layer was applied and dried in the same manner as in Examples 1 and 2 and Comparative Examples 1 to 3, and the X of each piezoelectric thin film was dried. The degree of orientation of the (100) plane was derived by measuring the line diffraction (2θ / θ method) with an X-ray diffractometer (RINT2100 manufactured by Rigaku Corporation) (see Table 2). Here, the environment, such as no wind on the hot plate and the shielding plate, is the same as in Examples 1 and 2 and Comparative Examples 1 to 3. FIG. 10 shows the relationship between the Ti amount ratio in atomic% and the (100) plane orientation degree (%) of PZT derived by the above-described method. When the Ti content ratio on the surface of the orientation control layer is 14.88 atomic%, the (100) plane orientation degree of PZT changes critically, and when it is 14.88 atomic% or less, the (100) plane orientation degree of PZT is high. There was found.

(Heating process conditions when forming the orientation control layer)
The degree of orientation of the (100) plane of the piezoelectric thin film varies depending on the heating process conditions (drying temperature and drying time) when forming the orientation control layer, and the degree of orientation of the (100) plane improves as the thermal load decreases ( (See Table 2). From FIG. 10 and Table 2, the preferable drying temperature T (° C.) and drying time t (minute) of the orientation control layer can be defined by the following formula (1).

（但し ５０≦Ｔ≦４５０， ０＜ｔ＜３０ ）

(However, 50 ≦ T ≦ 450, 0 <t <30)

Equation (1) is assumed to be an arithmetic sequence in increments of 10 ° C. for temperature and in increments of 1 minute for temperature from experimental data points of orientation degree (T = 200, 280 ° C., t = 1, 5, 10 minutes). The degree of orientation for each temperature and time condition is calculated. The critical point of the degree of orientation shown in FIG. 10 is set to 85%, and the boundary condition (temperature, time) point is derived. The relational expression of temperature and time is T = A × t ^ (− B) + C
Then, the coefficients of A, B, and C were calculated and derived by the least square method fitting of the boundary condition point obtained above and this relational expression.

  Here, the drying temperature and drying time conditions of the orientation control layers of Examples 3 to 11 showing the high (100) plane orientation degree of the piezoelectric thin film satisfy Expression (1). Comparative Examples 4 to 8 do not satisfy the formula (1). It was confirmed that the Ti content ratio on the surface of the orientation control layer can be reduced to 14.88 atomic% or less by satisfying the formula (1).

DESCRIPTION OF SYMBOLS 1 Substrate substrate 2 Intermediate layer 3 Electrode layer 4 Orientation control layer 21 Liquid discharge head substrate 21A Opening 22 Ink discharge port 23 Pressure chamber 24 Nozzle plate 25 Actuator 26 Vibration plate 27 Piezoelectric thin film 28 Lower electrode 29 Upper electrode 30 Piezoelectric body element

Claims (13)

A base substrate layer containing at least SiO ₂ or SiN on the surface;
An intermediate layer including at least one of Ti and TiO ₂ on the base substrate layer, and an electrode layer including Pt on the intermediate layer;
A piezoelectric film-forming substrate, wherein the electrode layer has a thickness of 40 nm or more and 1000 nm or less, and Ti is not detected on the surface of the electrode layer by elemental quantitative analysis. A base substrate layer containing at least SiO ₂ or SiN on the surface;
An intermediate layer including at least one of Ti and TiO ₂ on the base substrate layer; an electrode layer including Pt on the intermediate layer;
An orientation control layer on the electrode layer,
The orientation control layer contains Pb, O, and Ti, and the Ti in the Pb, O, and Ti elements on the surface of the orientation control layer is 14.88 atomic% or less. .   The piezoelectric film-forming substrate according to claim 2, wherein the orientation control layer contains an organic substance containing Pb.   The piezoelectric film-forming substrate according to claim 3, wherein the orientation control layer contains an organic material containing Ti.   5. The piezoelectric film-forming substrate according to claim 1, wherein the intermediate layer has a thickness of 2 nm to 50 nm, and the electrode layer has a thickness of 40 nm to 1000 nm.   A piezoelectric substrate, comprising a piezoelectric body provided on a surface of the piezoelectric film-forming substrate according to claim 1.   The piezoelectric substrate according to claim 6, wherein the piezoelectric body is PZT (lead zirconate titanate).   A liquid discharge head comprising the piezoelectric substrate according to claim 6. A method for manufacturing a substrate for piezoelectric film formation,
Forming an intermediate layer containing at least one of Ti and TiO ₂ on a base substrate layer containing at least SiO ₂ or SiN on the surface;
Forming an electrode layer containing Pt on the intermediate layer;
Forming an orientation control layer containing Pb, O, Ti on the surface of the electrode,
A manufacturing method characterized in that a temperature T (° C.) and a time t (minute) applied to the piezoelectric substrate during the step of forming the orientation control layer satisfy the following formula (1).

(However, 50 ≦ T ≦ 450, 0 <t <30)   The manufacturing method according to claim 19, wherein the intermediate layer has a thickness of 2 nm to 50 nm, and the electrode layer has a thickness of 40 nm to 1000 nm.   The step of forming the orientation control layer includes a step of coating a coating liquid containing an organic metal oxide containing Pb and Ti and an organic solvent on the electrode to form a coating layer, and the coating layer The manufacturing method according to claim 9 or 10, wherein a drying temperature and a drying time in the drying step are a temperature T and a time t satisfying the formula (1).   A coating liquid containing a piezoelectric precursor and an organic solvent is applied to the surface of the piezoelectric film-forming substrate according to claim 1, and the coating liquid is dried to be applied. Production of piezoelectric substrate having a step of forming a layer, a step of drying the coating layer to form a dry coating layer, and a step of firing the dry coating layer to form a piezoelectric thin film Method.   13. The manufacturing method according to claim 12, wherein the piezoelectric precursor is a thermally decomposable composite organometallic oxide prepared from an organometallic compound containing Pb, an organometallic compound containing Zr, and an organometallic compound containing Ti. .

Images