JP2000299513A - Piezoelectric element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesion between a piezoelectric body thin film and a lower electrode by setting the X-ray diffraction intensity of the piezoelectric body thin film of a Perovskite-type crystal and the electrode material of platinum and titanium being provided at the side of the piezoelectric body thin film to each specific expression. SOLUTION: The X-ray diffraction intensity of a piezoelectric body thin-film layer 41 is set so that an expression of I100/(I100+I110+I111)>=0.5 can be met. In this case, the X-ray diffraction intensity of the <100> surface of a Perovskite-type crystal, that of <110> surface, and that of <111> surface are set to I100, I110, and I111, respectively. Also, a lower electrode 32 is made of a platinum layer 322 and a titanium layer 321, and the X-ray diffraction intensity is set so that an expression of IBE/I100<=0.05 can be met. However, the X-ray diffraction intensity where a diffraction angle 2θ is equal to 360±0.3 deg. is set to IBE when Cu-Kβ is used as a power supply when measuring X-ray diffraction. As a result, the piezoelectric thin film and the lower electrode have the same orientation performance, thus improving the adhesion property between the piezoelectric thin film and the lower electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element used for an ink jet recording head or the like, and more particularly to a piezoelectric element having good adhesion between an electrode and a piezoelectric thin film, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A piezoelectric element has a piezoelectric thin film in which lead zirconate titanate (hereinafter referred to as "PZT") is crystallized by heat treatment between a lower electrode and an upper electrode. The method of manufacturing a piezoelectric element called a sol-gel method,
A sol (precursor) composed of a metal alkoxide solution is applied on the lower electrode, and the sol is dried and degreased, and then heat-treated for crystallization. The crystal of the piezoelectric thin film has several orientations.

Conventionally, since the orientation of the crystal affects the characteristics of the piezoelectric element, various studies have been conducted on the relationship between the manufacturing method and the orientation. For example, a paper by T. Tani et al. (Mater. Res. Soc. Symp. Proc. 310 (199
3) 269) describes considerations on degreasing temperature and orientation. According to this paper, as the degreasing temperature is increased from low to high, the main orientation changes from <111> orientation to <1.
00> orientation. Also, C.
A paper by Kim et al. (Journal of Material Science, 3
2 (1997) 1213) also discusses the relationship between degreasing temperature and orientation. It is described that when the degreasing temperature is low, the organic substance remains in the sol and the <111> orientation increases, and when the degreasing temperature is high, the organic substance decreases and the <100> orientation becomes dominant. That is, the orientation of the piezoelectric thin film is controlled by adjusting the degreasing temperature.

[0004]

However, even with the piezoelectric element manufactured as described above, there have been cases where the adhesion between the piezoelectric thin film and the lower electrode is poor. When the piezoelectric element is used as a piezoelectric actuator for a long period of time, the piezoelectric thin film peels off from the lower electrode, thereby reducing the reliability of the device.

[0005] In view of the above problems, an object of the present invention is to provide a piezoelectric element having good adhesion between a piezoelectric thin film and a lower electrode. Another object of the present invention is to provide a highly reliable ink jet recording head and printer.

[0006]

As described in the above-mentioned Tani's paper, the orientation of a piezoelectric thin film changes depending on the orientation performance of an electrode in addition to the degreasing temperature. If the orientation performance of the lower electrode does not match the orientation of the piezoelectric thin film, it is considered that the adhesion between them is deteriorated. It can be seen that it is important to manufacture the piezoelectric element in such a manner that the orientations of the two are matched.

Therefore, in the piezoelectric element of the present invention, in the crystal structure, the X-ray diffraction intensity of the <100> plane of the perovskite crystal is I ₁₀₀ , and that of the <110> plane is I ₁₁₀ , < ₁₁₀ .
Its 111> plane when the _{I 111,} the piezoelectric thin film is set to satisfy the _{I 100 / (I 100 + I} 110 + I 111) ≧ 0.5, platinum provided on the piezoelectric thin film side And titanium as an electrode material, and C as a radiation source in X-ray diffraction measurement of the electrode material.
When u-Kβ is used, the diffraction angle 2θ is 36 ° ± 0.
The X-ray diffraction intensity is 3 ° when the _{I BE,} characterized in that and a lower electrode is set to satisfy the _I BE _{/ I 100} ≦ 0.05. Here, 36 ° related to the lower electrode material
The X-ray diffraction, the peak due to the interaction between the light source (radiation source) and Pt in the X-ray diffraction measurement, is believed to contain a three peak by peak or Pt-Ti alloy according to TiO _2. It is difficult to determine which cause is the diffraction intensity.

Here, it is preferable that the thickness of the platinum layer of the lower electrode relative to the titanium layer is set to 10 or more. The platinum layer of the lower electrode has a crystal grain size of 50 nm.
Preferably, it is set in the range of 100 nm to 100 nm.

In the piezoelectric element of the present invention, the X-ray diffraction intensity of the <100> plane of the perovskite crystal is I ₁₀₀ , and that of the <110> plane is I ₁₁₀ , <11.
1> The surface of the piezoelectric thin film which is set so as to satisfy I ₁₁₁ / (I ₁₀₀ + I ₁₁₀ + I ₁₁₁ ) ≧ 0.5 when the surface is I _111, and the platinum provided on the piezoelectric thin film side And titanium as an electrode material, and C as a radiation source in X-ray diffraction measurement of the electrode material.
When u-Kβ is used, the diffraction angle 2θ is 36 ° ± 0.
When the X-ray diffraction intensity of 3 ° is I _BE , a lower electrode is set to satisfy I _BE / I ₁₁₁ ≦ 0.05. Here, the platinum layer of the lower electrode preferably has a crystal grain size of 50 nm or less.

According to the present invention, there is provided a method for manufacturing a piezoelectric element in which a piezoelectric thin film is sandwiched between electrodes, the ability of the electrode to orient the crystal of the precursor film before crystallizing the piezoelectric thin film in a specific crystal direction. A method for manufacturing a piezoelectric element, characterized in that an electrode and a precursor film are combined and crystallized such that the ability to orient crystals in a specific crystal direction in the precursor film is in the same crystal direction.

For example, in this manufacturing method, a piezoelectric thin film in which <100> orientation is predominant is manufactured by forming a precursor film before crystallizing the piezoelectric thin film with a sol containing no organic substance as an additive. It is characterized by the following.

For example, in this manufacturing method, the precursor film before the crystallization of the piezoelectric thin film is formed by adding an organic substance as an additive to the precursor film.
By forming with a sol containing 2 mol / l or more,
111> is characterized by producing a piezoelectric thin film in which orientation is predominant.

The method for manufacturing a piezoelectric body according to the present invention includes a step of thermally decomposing the precursor film at a temperature of 350 ° C. or higher.

The ink jet recording head of the present invention includes the piezoelectric element of the present invention as a piezoelectric actuator. The printer of the present invention includes the ink jet recording head of the present invention as a printing unit.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. (Embodiment 1) The present embodiment relates to a piezoelectric element having a piezoelectric thin film of <100> preferred orientation, an ink jet recording head and a printer having the piezoelectric element.
FIG. 6 is an enlarged sectional view of a piezoelectric element portion of the ink jet recording head according to the first embodiment. As shown in FIG. 6, the piezoelectric element 40 of the present embodiment is configured by sandwiching a piezoelectric thin film layer 41 between a lower electrode 32 and an upper electrode 42. In the figure, the lower electrode 32 is formed as a common electrode on the entire diaphragm 30 of the ink jet recording head, but the lower electrode may be formed only in the region of the piezoelectric element 40.

The lower electrode 32 is an electrode paired with the upper electrode 42 for applying a voltage to the piezoelectric thin film layer 41,
A titanium layer 321 containing titanium and a platinum layer 322 provided on the piezoelectric thin film side are provided. The reason why the platinum layer is provided on the piezoelectric thin film side is that when the precursor of the piezoelectric thin film is crystallized using platinum as a base, the piezoelectric thin film has a strong tendency to be <100> oriented.

In particular, the lower electrode 32 is provided on the piezoelectric thin film side, contains a platinum layer and titanium as an electrode material, and has a diffraction angle 2θ when Cu-Kβ is used as a radiation source in X-ray diffraction measurement of the electrode material. X is 36 ° ± 0.3 °
The ray diffraction intensity when a _{I BE,} is characterized in that it is set to satisfy _I BE _{/ I 100} ≦ 0.05. Characteristic X
This is the intensity when a Cu-Kα line and a Cu-Kβ line are used for the line.

As shown in FIG. 1, the lower the peak intensity of the lower electrode with respect to the peak intensity of the <100> orientation, the lower the peak intensity of the <100> orientation in the comparison of the peak intensity in the X-ray diffraction characteristics (ie, the crystal abundance per orientation). This is because the adhesion becomes higher. The boundary at which suitable adhesion can be secured is approximately 0.05
It is.

The platinum layer 32 with respect to the titanium layer 321
The thickness of 2 is set to 10 or more. As shown in FIG. 2, when the amount of platinum is large, the smoothness of the crystal growth surface of the electrode is high and <1.
This is because 00> orientation tends to occur.

Further, the platinum layer 322 has a crystal grain size of 5
Preferably, it is set in the range of 0 nm to 100 nm. If the crystal grain size is large as described above, titanium is unlikely to diffuse toward the piezoelectric thin film layer, and a crystal having a <100> orientation is easily generated.

The piezoelectric thin film layer 41 is a crystal of a piezoelectric ceramic formed from a sol of a metal alkoxide solution, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), niobium, or the like. Those to which a metal such as nickel or magnesium is added are used. The composition is appropriately selected in consideration of the characteristics and use of the piezoelectric element. Specifically, lead titanate (PbTiO ₃ ), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), lead zirconate (PbZrO ₃ ), lanthanum lead titanate ((P
b, La), TiO ₃ ), lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ), or lead zirconium titanate magnesium niobate (Pb (Zr,
Ti) (Mg, Nb) O ₃ ) or the like can be used.
If the piezoelectric thin film layer 41 is too thick, a high driving voltage is required. On the other hand, if the thickness is too small, the film thickness cannot be made uniform, and the characteristics of each piezoelectric element separated after the etching will vary, or the number of manufacturing steps will increase, making it impossible to manufacture at a reasonable cost. Therefore, the piezoelectric thin film layer 41
A thickness of about 00 nm to 3000 nm is preferred.

In particular, the piezoelectric thin film layer 41 has a crystal structure in which the X-ray diffraction intensity of the <100> plane of the perovskite crystal is I ₁₀₀ , and that of the <110> plane is I ₁₁₀ , <111.
> Its surface when the _{I 111,} are set so as to satisfy the _{I 100 / (I 100 + I} 110 + I 111) ≧ 0.5. This is because the lower electrode surface is made of platinum and has <100> orientation performance, so that the <100> orientation inevitably prevails in the orientation of the piezoelectric thin film layer.

This method of manufacturing a piezoelectric thin film is characterized in that a precursor film before crystallization of the piezoelectric thin film is formed of a sol containing no organic matter as an additive.
This is because, as shown in FIG. 3, when the precursor containing no organic substance is heat-treated after degreasing, the precursor is likely to be in the <100> orientation.

The upper electrode film 42 is the other electrode for applying a voltage to the piezoelectric thin film layer, and is made of a conductive material, for example, platinum (Pt) having a thickness of 0.1 μm. The insulating film 31 is a main material of the diaphragm 30. The insulating film 31 is made of a material having no conductivity, for example, silicon dioxide formed by thermally oxidizing a silicon substrate. And it is deformed by the volume change of the piezoelectric layer,
The pressure inside the cavity 21 can be instantaneously increased.

Next, the structure of the ink jet recording head will be described. As shown in FIG. 8, the ink jet recording head 1 includes a nozzle plate 10, a pressure chamber substrate 20, a vibration plate 3
0 and the piezoelectric element 40. Pressure chamber substrate 20
Has a cavity (pressure chamber) 21, a side wall (partition wall) 22, a reservoir 23, and a supply port 24. The cavity 21 is a space formed by etching a substrate such as silicon to store ink and the like. The side wall 22 is formed so as to partition between the cavities 21. The reservoir 23 is formed as a flow path for commonly filling each cavity 21 with ink. The supply port 24 is provided from the reservoir 23 to each cavity 21
Is formed so as to be able to introduce ink.

The nozzle plate 10 is bonded to the pressure chamber substrate 20 such that the nozzle holes 11 are arranged at positions corresponding to the cavities 21 provided in the pressure chamber substrate 20. On the side of the pressure chamber substrate 20 opposite to the nozzle plate 10, the diaphragm 3 on which the piezoelectric element 40 shown in FIG.
0 is attached. Each piezoelectric element 40 is arranged at a position corresponding to the cavity 21.

Further, the structure of a printer using the above-mentioned ink jet recording head will be described. As shown in FIG. 9, the printer according to the present embodiment is provided with a tray 3 and a discharge port 4 in a main body 2. Inside the main body 2, the inkjet recording head 1 is provided so as to be transported across the paper 5 supplied from the tray 3 by a transport mechanism (not shown). The ink jet recording head 1
A print signal corresponding to a control signal transmitted from a computer or the like is supplied to each piezoelectric element 40.

The printing principle of the above-described printer and ink jet recording head will be described. When a control signal is transmitted from the computer, a corresponding print signal is supplied between the lower electrode 32 and the upper electrode 42 of the piezoelectric element 40 corresponding to one of the cavities 21.

When no voltage is applied between the lower electrode 32 and the upper electrode 42 of the piezoelectric element 40, no distortion occurs in the piezoelectric thin film layer 41. In the cavity 21 in which the piezoelectric element 40 to which this voltage is not applied is provided,
No pressure change occurs, and no ink droplet is ejected from the nozzle hole 11.

On the other hand, when a constant voltage is applied between the lower electrode 32 and the upper electrode 42 of the piezoelectric element 40, the piezoelectric thin film layer 41 is distorted. In the cavity 21 in which the piezoelectric element 40 to which the voltage is applied is provided, the vibration plate 30 is largely bent. Therefore, the pressure in the cavity 21 increases instantaneously, and ink droplets are ejected from the nozzle holes 11. As a result, printing is performed on the paper 5 in accordance with the control signal.

Next, a method for manufacturing the piezoelectric element of the present invention will be described. This manufacturing method uses a sol-gel method in a broad sense.

First, a sol as a precursor of the piezoelectric thin film layer is prepared. Titanium tetraisopropoxide (Ti (OC ₃ H ₇ ) ₄ ) and pentaethoxy niobium (N) in 2-n-butoxyethanol as basic solvents for the solute
b (OC ₂ H ₅ ) ₅ ) is added and stirred to dissolve them. Then monoethanolamine is added to the solution and stirred. The action of monoethanolamine is a function as a chelating agent for chemically stabilizing the two metal alkoxides so that the metal alkoxides do not undergo hydrolysis. In particular, no additives are added. This is because if an organic substance remains in the precursor, the orientation becomes <111> dominant.

Further, lead acetate trihydrate, zirconium acetylacetonate and magnesium acetate pentahydrate are mixed. The mixture is heated and dissolved at 80 ° C. to 120 ° C.

In parallel with the production of the sol, an insulating film 31 is formed on the pressure chamber substrate 20. As the silicon substrate 20, for example, a silicon substrate of about 200 μm is used. The insulating film 31 includes 1
It is formed to a thickness of about μm. For the production of the insulating film, a known thermal oxidation method or the like is used.

Next, a lower electrode is formed. First, a titanium layer 321 and then a platinum layer 322 are formed. The thickness ratio between the two is set to be 1:10 or more. For example, a titanium layer is formed with a thickness of 0.01 μm, and a platinum layer is formed with a thickness of 0.1 μm. As a forming method, a direct current sputtering method, an evaporation method, or the like is used.

Next, a piezoelectric thin film layer 41 is formed on the lower electrode 32 using the sol. First, the sol is applied on the lower electrode to a certain thickness. For example, when a known spin coating method is used, 500 rotations per minute is performed for 30 seconds and 15 minutes per minute.
The coating is performed at 00 rotations for 30 seconds and finally at 500 rotations per minute for 10 seconds. After the application, the coating is dried at a constant temperature (for example, 180 degrees) for a certain time (for example, about 10 minutes). Drying causes the solvent butoxyethanol to evaporate. After drying, a predetermined high temperature or higher (for example, 350 ° C.) in an air atmosphere
For a certain period of time (30 minutes). By degreasing, the organic ligand coordinated to the metal is thermally decomposed, and the metal is oxidized to a metal oxide. In this process, the organic matter disappears almost completely from the sol. The steps of coating, drying, and degreasing are repeated a predetermined number of times, for example, eight times, and eight thin film layers are stacked.
By these drying and degreasing, a metal-oxygen-metal network is formed between the metal alkoxide and the acetate in the solution through thermal decomposition of the ligand.

After the formation of the four thin film layers and the formation of the eight thin film layers, rapid heat treatment (RTA: Ra
pid Thermal Annealing). For the baking treatment, a lamp annealing furnace or the like which is usually used is used.

The perovskite crystal structure having any crystal structure is formed from the precursor gel in an amorphous state by the above-described calcination treatment. At this time, the platinum layer 322 of the lower electrode 32 has <100> orientation performance, the crystal grain size is appropriate, and the crystallization condition of the precursor is <100>.
Since it is adjusted so as to easily cause orientation, <10
0> The piezoelectric thin film layer 41 in which the orientation is dominant is formed.

After the piezoelectric thin film layer 41 has been crystallized, a technique such as an electron beam evaporation method or a sputtering method is used thereon.
The upper electrode 42 is formed. The material of the upper electrode is platinum (P
t) and the like are used. The thickness is about 100 nm.

Through the above steps, the original form of the piezoelectric element is completed. By etching this piezoelectric element into a shape suitable for the application location, it is possible to operate as the piezoelectric element of the present invention. If the pressure chamber substrate 20 is further etched and bonded to the nozzle plate 10 and housed in a predetermined housing,
It is possible to manufacture the ink jet recording head of the present embodiment.

(Example) <100> according to the above embodiment.
A piezoelectric element having a predominant orientation was manufactured. FIG. 4 shows the X-ray diffraction characteristics (2θ). As shown in FIG. 4, as the crystal orientation, the <100> orientation is extremely large, and the ratio of the <100> orientation to all the orientations is 0.5 or more.

Table 1 shows the abundance ratios of crystal orientations in Examples 1 and 2 prepared without adding polyethylene glycol (PEG) to the sol and Comparative Examples prepared with the added sol.
The relationship between the ratio of the electrode material to the orientation and the orientation performance of the piezoelectric thin film layer and the lower electrode and the adhesion are shown below.

[0043]

[Table 1] As can be seen from Table 1, when the sol was manufactured without adding an organic substance, the piezoelectric thin film layer became dominant in the <100> orientation, and under the condition where the electrode was made to have the <100> orientation, the adhesion between the two was poor. It's getting better. On the other hand, when the sol is manufactured by adding an organic substance, the piezoelectric thin film layer becomes dominant in the <111> orientation, and therefore, the adhesion between the two is deteriorated under the condition that the electrode has the <100> orientation performance.

(Embodiment 2) In the present embodiment, <111>
The present invention relates to a piezoelectric element having an oriented piezoelectric thin film, and to the piezoelectric element. FIG. 7 is an enlarged sectional view of a piezoelectric element portion of the ink jet recording head according to the second embodiment. As shown in FIG. 7, the piezoelectric element 40b of the present embodiment is different from the first embodiment in the structure of the lower electrode 32b. The lower electrode 32b is formed as a common electrode on the entire diaphragm 30 of the ink jet recording head.
As in the first embodiment, the lower electrode may be formed only in the region of FIG.

The lower electrode 32b of this embodiment includes a titanium layer 321 containing titanium, a platinum layer 322, and a titanium layer 323 containing titanium provided on the piezoelectric thin film side.
Embodiment 2 is different from Embodiment 1 in that a titanium layer is formed on the piezoelectric thin film side and the crystal of the piezoelectric element is different. The provision of the titanium layer on the side of the piezoelectric thin film layer is achieved by crystallizing the precursor of the piezoelectric thin film using titanium as a base to make the piezoelectric thin film <111>.
This is because orientation tends to be strong.

The lower electrode 32b is provided on the piezoelectric thin film side, includes a platinum layer and titanium as electrode materials, and has a diffraction angle 2θ when Cu-Kβ is used as a radiation source in X-ray diffraction measurement of the electrode material. When the X-ray diffraction intensity of 36 ° ± 0.3 ° is I _BE , it is characterized in that it is set so as to satisfy I _BE / I ₁₁₁ ≦ 0.05. Characteristic X
This is the intensity when a Cu-Kα line and a Cu-Kβ line are used for the line.

As shown in FIG. 1, in the comparison of the peak intensities (that is, the amount of crystals for each orientation) in the X-ray diffraction characteristics, the lower the peak intensity of the platinum-titanium alloy with respect to the peak intensity of the <111> orientation, This is because the adhesion between both becomes high. The boundary at which a suitable adhesiveness can be secured is approximately 0.05.

The platinum layer 322 has a crystal grain size of 50 nm.
It is preferable to set the following. This is because, if the crystal grain size is attained, if the grain size of the platinum layer is reduced, titanium is easily diffused to the piezoelectric thin film side, and crystals of <111> orientation are easily formed.

The composition of the piezoelectric thin film layer 41 is the same as that of the first embodiment, but the crystal orientation is different. That is, the piezoelectric thin film layer has the X-ray diffraction intensity of the <100> plane of the perovskite crystal as I ₁₀₀ , that of the <110> plane as I ₁₁₀ ,
Its <111> faces when the _{I 11 1,} are set so as to satisfy the _{I 111 / (I 100 + I} 110 + I 111) ≧ 0.5.

The composition of the other layers is the same as that of the first embodiment, and the description is omitted.

Regarding the production method, the amount of the organic substance such as PEG to be added when forming the sol is determined so that the organic substance does not completely evaporate at the thermal decomposition temperature in the degreasing step and remains in the precursor. Embodiment 2 differs from Embodiment 1 in that the amount is added.

Another difference is that the <111> orientation of the lower substrate 32b is increased by applying a heat treatment (for example, at 800 ° C. for about 30 minutes) after manufacturing the lower substrate 32b.

(Example) According to the above embodiment, <111>
A piezoelectric element having a predominant orientation was manufactured. FIG. 5 shows the X-ray diffraction characteristics (2θ). As shown in FIG. 5, as the crystal orientation, the <111> orientation is very large, and the abundance ratio of the <111> orientation to all the orientations is 0.5 or more.

Table 2 shows the crystal orientation ratio, the ratio of the electrode material to the <100> orientation, and the piezoelectric material in Example 3 in which PEG was added to the sol and Comparative Example in which PEG was not added. The relationship between the combination of the alignment performance of the thin film layer and the lower electrode and the adhesion are shown.

[0055]

[Table 2] As can be seen from Table 1, when the sol was produced by adding an organic substance, the piezoelectric thin film layer became dominant in the <111> orientation, and under the condition that the electrode was made to have the <111> orientation, the adhesion between the two was poor. It's getting better. On the other hand, when the sol is manufactured without adding an organic substance, the piezoelectric thin film layer becomes dominant in the <100> orientation, and therefore, the adhesion between the two is deteriorated under the condition that the electrode has the <111> orientation performance. .

(Other Modifications) The present invention can be applied to various modifications without depending on the above embodiments. For example, in the above embodiment, the piezoelectric thin film layer is crystallized using the sol-gel method. However, the piezoelectric thin film layer may be crystallized from an organic metal precursor by a MOD method, a coprecipitation method, or a hydrothermal method. Good. Further, the piezoelectric element manufactured by the present invention is not limited to the piezoelectric element of the above-described ink jet recording head, but also a nonvolatile semiconductor storage device, a thin film capacitor,
Ferroelectric devices such as pyroelectric detectors, sensors, surface acoustic wave optical waveguides, optical storage devices, spatial light modulators, frequency doublers for diode lasers, dielectric devices, pyroelectric devices, piezoelectric devices , And the manufacture of electro-optical devices.

[0057]

According to the present invention, since the piezoelectric thin film and the lower electrode have the same orientation performance, it is possible to provide a piezoelectric element having good adhesion between the piezoelectric thin film and the lower electrode. it can. Further, according to the present invention, since the piezoelectric element having good adhesion between the piezoelectric thin film and the lower electrode is provided, it is possible to provide a highly reliable ink jet recording head and printer.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the peak intensity ratio of an electrode material to the peak intensity of <100> orientation or <111> orientation and adhesion.

FIG. 2 is a diagram showing an existing ratio of crystal orientation corresponding to a change in the thickness of a platinum layer with respect to the thickness of a titanium layer.

FIG. 3 is a view showing the ratio of the presence of crystal orientation to the amount of residual organic substances in a sol.

FIG. 4 is an X-ray diffraction characteristic diagram (2θ) in the example of the first embodiment.

FIG. 5 is an X-ray diffraction characteristic diagram (2θ) in the example of the second embodiment.

FIG. 6 is a cross-sectional view illustrating a laminated structure of the piezoelectric element according to the first embodiment.

FIG. 7 is a cross-sectional view illustrating a laminated structure of a piezoelectric element according to a second embodiment.

FIG. 8 is an exploded perspective view of the ink jet recording head of the embodiment.

FIG. 9 is a perspective view of the printer of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Nozzle plate 20 ... Pressure chamber substrate 30 ... Vibration plate 31 ... Insulating film 32 ... Lower electrode 321, 323 ... Titanium layer 322 ... Platinum layer 40 ... Piezoelectric element 41 ... Piezoelectric thin film layer 42 ... Upper electrode 11 ... Nozzle 21 …cavity

Claims (11)

[Claims] 1. A piezoelectric device having a piezoelectric thin film having an electromechanical conversion function, X-rays diffraction intensity of <100> plane of the perovskite-type crystal in the crystal structure of I _{1 00,} its _<110> faces I
₁₁₀ , a piezoelectric thin film set so as to satisfy I ₁₀₀ / (I ₁₀₀ + I ₁₁₀ + I ₁₁₁ ) ≧ 0.5, where I ₁₁₁ is the surface of the <111>plane; The electrode includes platinum and titanium as electrode materials, and has a diffraction angle 2θ of 36 when Cu-Kβ is used as a radiation source in X-ray diffraction measurement of the electrode material.
The ° ± 0.3 a ° X-ray diffraction intensity when a _{I BE,} piezoelectric, characterized in that it and a lower electrode is set to satisfy the _I BE _{/ I 100} ≦ 0.05 Body element. 2. The piezoelectric element according to claim 1, wherein the thickness of the platinum layer with respect to the titanium layer of the lower electrode is set to 10 or more. 3. The piezoelectric element according to claim 1, wherein the platinum layer of the lower electrode has a crystal grain size set in a range of 50 nm to 100 nm. 4. A piezoelectric element having a piezoelectric thin film having an electromechanical conversion function, X-rays diffraction intensity of <100> plane of the perovskite-type crystal in the crystal structure of I _{1 00,} its _<110> faces I
₁₁₀ , a piezoelectric thin film set so as to satisfy I ₁₁₁ / (I ₁₀₀ + I ₁₁₀ + I ₁₁₁ ) ≧ 0.5, where I ₁₁₁ is the surface of the <111>plane; The electrode includes titanium and platinum as electrode materials, and the diffraction angle 2θ is 36 when Cu-Kβ is used as a radiation source in X-ray diffraction measurement of the electrode material.
A lower electrode set to satisfy I _BE / I ₁₁₁ ≦ 0.05 when an X-ray diffraction intensity of ± 0.3 ° is I _BE. Body element. 5. The platinum layer of the lower electrode has a crystal grain size of 50 nm or less.
3. The piezoelectric element according to item 1. 6. An ink jet recording head comprising the piezoelectric element according to claim 1 as a piezoelectric actuator. 7. A printer comprising the ink jet recording head according to claim 6 as printing means. 8. A method for manufacturing a piezoelectric element in which a piezoelectric thin film is sandwiched between electrodes, wherein the electrode is oriented in a specific crystal direction and the precursor is crystallized before crystallization of the piezoelectric thin film. A method of manufacturing a piezoelectric element, comprising: crystallizing a combination of the electrode and the precursor film such that the ability to orient a crystal in a film in a specific crystal direction is in the same crystal direction. 9. The method for manufacturing a piezoelectric element according to claim 8, wherein the <100> orientation is predominant by forming the precursor film using a sol containing no organic substance as an additive. And a method for manufacturing a piezoelectric element. 10. The method for manufacturing a piezoelectric element according to claim 8, wherein the precursor film is formed of a sol containing an organic substance as an additive in an amount of 0.2 mol / liter or more, and thereby has a <111> orientation. A method for manufacturing a piezoelectric element, characterized by comprising a piezoelectric thin film in which is predominant. 11. The method according to claim 9, further comprising a step of thermally decomposing the precursor film at a temperature of 350 ° C. or higher.