CN100570918C - Piezoelectric element, inkjet head, angular velocity sensor, their manufacturing method, and inkjet recording device - Google Patents

Abstract

The invention discloses a piezoelectric body element, an inkjet head, an angular velocity sensor, their manufacturing method and an inkjet type recording device. A piezoelectric element includes two electrode films, and a piezoelectric laminated film composed of two piezoelectric thin films sandwiched between these electrode films and having a (111) plane preferentially oriented. The two-layer piezoelectric thin film is an aggregate of columnar particles continuously connected to each other. The average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film. The ratio of the thickness of the piezoelectric laminate film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is 20 or more and 60 or less.

Description

Piezoelectric element, inkjet head, angular velocity sensor, their manufacturing method, and inkjet recording device

technical field

The present invention relates to a piezoelectric element exhibiting an electromechanical conversion function, an inkjet head and an angular velocity sensor using the piezoelectric element, their manufacturing method, and an inkjet recording device using the inkjet head.

Background technique

Piezoelectric materials are materials that convert mechanical energy into electrical energy, or vice versa. As a representative example of the piezoelectric material, there is lead zirconate titanate (Pb(Zr,Ti)O ₃ , hereinafter referred to as PZT), which is an oxide having a perovskite crystal structure. The PZT of this perovskite crystal structure is bounded by a Zr/Ti ratio of Zr/Ti=53/47 at %, and when there is a lot of Zr, it becomes a rhombohedral crystal system, and when there is little Zr, it becomes a tetragonal crystal system. In addition, the largest piezoelectric displacement can be obtained in the <111> axis direction when it is a rhombohedral crystal system, and the largest piezoelectric displacement can be obtained in the <001> axis direction (c-axis direction) when it is a tetragonal crystal system. However, many piezoelectric materials are polycrystals composed of aggregates of crystal grains, and the crystal axes of the crystal grains point in different directions. Therefore, the arrangement of the spontaneously polarized Ps is also different.

However, along with the miniaturization of electronic devices in recent years, miniaturization of piezoelectric elements is also strongly demanded. In addition, in order to meet this requirement, piezoelectric elements are being used not in the form of sintered bodies that have been widely used in the past, but in the form of thin films that are significantly smaller in volume than the sintered bodies, and piezoelectric elements have become thinner. research and development is flourishing.

Here, although piezoelectric thin films made of PZT-based piezoelectric materials are generally more likely to be oriented on the (111) plane, this orientation rate is low and coexists with other orientation planes, so the piezoelectric properties of the piezoelectric element are poor. low, the difference is large.

Then, the substrate, the electrodes, and the like were worked hard to manufacture piezoelectric thin films with the following (001) plane or (100) plane orientation.

For example, the spontaneous polarization Ps of PZT points to the <111> axis direction in the rhombohedral crystal system, and points to the <001> axis direction in the tetragonal crystal system. Therefore, in order to realize high piezoelectric properties even when thinned, the <111> axis direction must be perpendicular to the substrate surface in the rhombohedral system, and the <001> axis direction must be in the direction perpendicular to the substrate surface in the tetragonal system. is the direction perpendicular to the substrate surface. In addition, in order to make the degree of orientation almost 100%, conventionally, in the case of a tetragonal perovskite crystal structure, by sputtering using a target composed of a tetragonal PZT, at a temperature of 600 to 700°C, Crystallinity in which the <001> axis is oriented in a direction perpendicular to the surface is directly formed on a single crystal substrate composed of magnesium oxide (hereinafter, MgO) with a rock-salt crystal structure on which the crystal orientation (100) plane protrudes from the surface. Good PZT thin film (for example, refer to Patent Document 1 and Non-Patent Document 1). At this time, if a piezoelectric layer consisting of Zr-free PbTiO ₃ and (Pb,La)TiO ₃ with a thickness of 0.1 μm is formed as a PZT thin film on the Pt electrode oriented on the (100) plane by sputtering If a PZT thin film with a thickness of 2.5 μm is formed on it, it is difficult to form a layer with low crystallinity composed of Zr oxide at the initial stage of the formation of the PZT thin film, and a PZT thin film with higher crystallinity can be obtained. That is, a PZT thin film having a degree of (001) plane orientation (α(001)) of approximately 100% can be obtained. Here, the degree of orientation α(001) is defined by α(001)=I(001)/ΣI(hk1). ΣI(hk1) is the sum of diffraction peak intensities from each crystal plane in PZT with a perovskite crystal structure having a 2θ of 10 to 70° when Cu-Kα rays are used in the X-ray diffraction method. In addition, since (002) plane and (200) plane and (001) plane and (100) plane are equipotential planes, they are not included in ΣI(hk1).

However, at this time, there is a problem that not only the price of the piezoelectric element is high because the MgO single crystal substrate is used as the base substrate, but also the price of the inkjet head using the piezoelectric element becomes high. . Also, there is a disadvantage that the substrate material is also limited to MgO single crystal.

Therefore, in order to form a (001) plane or (100) plane crystal orientation film of a perovskite type piezoelectric material such as PZT on an inexpensive substrate such as silicon, the following various methods have been developed.

For example, Patent Document 2 shows that PZT or a PZT precursor solution containing lanthanum is coated on a Pt electrode oriented on the (111) plane. First, by thermally decomposing the precursor solution at 150 to 550° C., Then, it is heat-treated at 550-800° C. to crystallize (sol-gel state interchange (solgel) method), and a (100) plane-preferential orientation film of PZT can be produced.

Furthermore, Patent Document 3 discloses a method of controlling the crystal orientation of a PZT film formed on an iridium lower electrode by forming an extremely thin titanium layer on the iridium lower electrode. In this method, a bottom layer mainly composed of zirconia is formed on a substrate such as silicon, a lower electrode containing iridium is formed on the bottom layer, an extremely thin titanium layer is formed on the bottom electrode, and a layer containing iridium is formed on the titanium layer. An amorphous piezoelectric precursor film of metal elements and oxygen elements is heat-treated at high temperature to crystallize the amorphous film (sol-gel state interchange (solgel) method) to generate a perovskite-type piezoelectric film. Electrode film. In this method, the crystal orientation of piezoelectric thin films such as PZT can be controlled by the thickness of the titanium layer, and a (111) plane oriented film can be obtained when the thickness of the titanium layer is 10 to 20 nm.

Furthermore, Patent Document 4 shows that when a piezoelectric thin film is formed by a sol-gel state exchange (solgel) method, a titanium layer of 4 to 6 nm is formed on a (111) plane-oriented Pt electrode to The titanium oxide of the titanium layer is a method in which a (100) plane-oriented PZT film can be obtained with titanium oxide as the core.

Also, Patent Document 5 shows that a sol having a concentration ratio of Zr and Ti of Zr/Ti=75/25 is applied by spin coating on a RuO ₂ lower electrode formed on a SrTiO ₃ substrate by a sputtering method. solution, make it overheated and dry to form a precursor film, and then use a sol solution with a concentration ratio of Zr and Ti of Zr/Ti=52/48 to form a multi-layer precursor film, and then sinter it at a high temperature of 900 ° C to form a precursor film. A method of synthesizing a PZT-based piezoelectric oxide thin film with a columnar structure (001) crystal orientation without cracks.

However, although the above-mentioned methods are superior in not using an expensive MgO single crystal substrate, for example, in order to form a piezoelectric thin film by the sol-gel state exchange (solgel) method, the MgO single crystal substrate As in the case of forming a piezoelectric thin film on a film, it is difficult to obtain a film with crystal orientation and good crystallinity when forming the film. Therefore, an amorphous piezoelectric thin film is first formed, and then a laminated film including the piezoelectric thin film is heat-treated on a substrate-by-substrate basis to preferentially orient the crystal axes in an appropriate direction.

In addition, if piezoelectric elements are mass-produced by the sol-gel state exchange (solgel) method, cracks due to volume changes are likely to occur in the amorphous piezoelectric precursor thin film in the degreasing process for removing organic matter. Furthermore, even in the process of crystallizing an amorphous piezoelectric precursor thin film by heating at a high temperature, cracks and detachment from the lower electrode film are likely to occur due to crystal changes.

In addition, in the sol-gel state exchange (solgel) method, there is a problem that since the thickness of the PZT film formed in one process (coating of the precursor solution and subsequent heat treatment) is about 100 nm, in order to To obtain the necessary thickness of 1 μm or more for the piezoelectric element, the above process must be repeated 10 times or more, which lowers the yield.

Then, as a method for solving these problems in the sol-gel state exchange (solgel) method, Patent Documents 6 and 7 disclose a relatively effective method of adding titanium and titanium oxide to the lower electrode. In particular, Patent Document 7 discloses a method in which a (100) plane-oriented PZT film can be obtained even by sputtering.

However, since it is not possible to directly obtain a perovskite-type PZT film on the lower electrode, but by initially forming a PZT film with an amorphous or pyrochlore-type crystal structure at a low temperature of 200°C or below, and then in an oxygen environment This PZT film is crystallized by heat treatment at a high temperature of 500-700°C. Therefore, like the sol-gel state exchange (solgel) method, there is a process of crystallization by heating at high temperature, which is easy to cause crystallization. The variation creates problems of cracking and detachment of the membrane from the lower electrode. In addition, the degree of (001) plane orientation or the degree of (100) plane orientation of the PZT film formed by the sol-gel state exchange (solgel) method or the sputtering method is 85% or less regardless of the method.

On the other hand, in Patent Document 3, methods other than the sol-gel state exchange (solgel) method (including the MOD method) in which an amorphous thin film is once formed and then converted into a crystalline thin film in a post-treatment such as heat treatment are tried. , That is, the film-forming method of directly forming a crystalline thin film without a crystallization process such as heat treatment, for example, using a sputtering method, a laser ablation method, or a CVD method to control the orientation of the PZT film so that it is formed on the surface. On an iridium (Ir) base electrode with an extremely thin titanium layer, an alignment film could not be obtained by methods other than the sol-gel state exchange (solgel) method. The reason is that in the sol-gel state exchange (solgel) method, the crystallization of the PZT film proceeds gradually from the lower electrode side to the upper electrode side, while in the CVD method, sputtering method, etc., the crystallization of the PZT film gradually progresses. Crystallization proceeds randomly without regularity, so orientation control is difficult.

Also, in Patent Document 8, as a method that does not require post-annealing, it is shown that an electrode thin film of noble metal alloys such as platinum and iridium containing titanium is formed by a sputtering method as a base electrode, and then sputtered on it. An oxide thin film whose crystals are oriented on the (001) plane, such as lead lanthanum titanate (PLT), which does not contain zirconium (Zr) in the composition, formed as an oxide with a perovskite crystal structure, is used as the initial layer. It is a substrate, and then a PZT thin film is formed on it by sputtering to obtain a PZT thin film whose crystal orientation is on the (001) plane. Furthermore, Patent Document 9 discloses a method in which a PZT film having a (001) crystal orientation can be directly obtained thereon using an electrode thin film of a noble metal alloy containing cobalt, nickel, manganese, iron, or copper. As described above, by forming a PZT film whose crystals are oriented on the (001) plane, which is a crystal orientation having a large piezoelectric constant, a piezoelectric thin film having high piezoelectric characteristics is formed. Since the piezoelectric thin film is preferentially oriented to the (001) plane in the direction perpendicular to the substrate surface, when it is a tetragonal perovskite structure, the polarization direction is the (001) plane, and the preferential orientation of the crystal is related to this With the same polarization direction, a higher piezoelectric constant appears. Therefore, the above-mentioned piezoelectric thin film is attracting attention as an actuator that can be used in various fields by causing a large displacement by applying a small voltage.

[Patent Document 1] Japanese Unexamined Patent Publication No. 10-209517

[Patent Document 2] Patent No. 3021930

[Patent Document 3] JP-A-2001-88294

[Patent Document 4] Japanese Unexamined Patent Publication No. 11-191646

[Patent Document 5] Japanese Patent Laid-Open No. 2000-208828 (page 3-4)

[Patent Document 6] JP-A-2000-252544

[Patent Document 7] Japanese Unexamined Patent Publication No. 10-81016

[Patent Document 8] Patent No. 3481235

[Patent Document 9] Japanese Unexamined Patent Publication No. 2004-79991

[Non-Patent Document 1] "Journal of Applied Physics", USA, American Physical Society, February 15, 1989, Vol. 65, No. 4, p.1666-1670

However, if a substrate having a smaller expansion coefficient than the piezoelectric thin film, such as a silicon single crystal substrate, is used as the substrate at the time of film formation, the piezoelectric thin film receives tensile stress from the substrate, and the one with a longer crystallographic axis ( 001) plane, that is, the polarization axis is oriented parallel to the substrate surface. In this state, when a voltage is applied in the film thickness direction, the polarization axis is rotated by 90°. Here, since the polarization axis is not easily rotated when the applied voltage is small, the desired piezoelectric characteristics cannot be obtained, and if the applied voltage is large, the polarization axis rotates toward the direction perpendicular to the substrate surface, and piezoelectricity The electrical characteristics become higher. As described above, the above-mentioned piezoelectric thin film has a high voltage dependence of piezoelectric characteristics.

In addition, there is a problem that when the polarization axis is rotated by 90°, the crystal is greatly distorted, and thus film detachment from the substrate occurs, and the durability of the actuator for obtaining a large actuator displacement is relatively low. Low.

Contents of the invention

The present invention has been made in view of the above points, and it is an object of the present invention to provide a piezoelectric characteristic that has low voltage dependence and that does not cause membrane detachment even when a high voltage is used to obtain a large actuator displacement. A highly durable and highly reliable piezoelectric element, an inkjet head and an angular velocity sensor using the piezoelectric element, their manufacturing method, and an inkjet recording device using the inkjet head.

In order to achieve the above objects, in the present invention, a piezoelectric multilayer film having a two-layer structure is formed on an electrode film made of a noble metal. At this time, by first forming the first piezoelectric thin film preferentially oriented to the (111) plane, and then forming the second piezoelectric thin film having a slightly different composition thereon, a piezoelectric thin film having a high degree of (111) plane orientation as a whole is formed. Piezoelectric laminated film.

Specifically, the first invention is aimed at such a piezoelectric element, including: a first electrode film, a first piezoelectric thin film disposed on the first electrode film, and a first piezoelectric thin film disposed on the first piezoelectric element. A piezoelectric laminated film formed of a second piezoelectric thin film on the film, and a second electrode film provided on the piezoelectric laminated film. That is, the first invention is a piezoelectric multilayer film including first and second electrode films and piezoelectric laminated films made of first and second piezoelectric thin films sandwiched between the first and second electrode films. Electrical components are objects.

Furthermore, in the present invention, the above-mentioned piezoelectric multilayer film is composed of a perovskite-type oxide preferentially oriented to a (111) plane of a rhombohedral system or a tetragonal system. The first and second piezoelectric thin films are aggregates of columnar particles that are in continuous contact with each other. The average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film. A ratio of the thickness of the piezoelectric laminate film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is not less than 20 and not more than 60.

In this way, the piezoelectric multilayer film composed of rhombohedral or tetragonal perovskite oxide can be preferentially oriented on the (111) plane on the first electrode film. Therefore, the variation in piezoelectric characteristics can be kept low, and the reliability can be improved. In other words, since the piezoelectric element is used to apply an electric field in a direction perpendicular to the film surface of the piezoelectric laminated film, especially in the rhombohedral perovskite-type PZT film, because ( 111) plane orientation, so that the <111> polarization axis direction is parallel to the direction of the electric field, and larger piezoelectric characteristics can be obtained. In addition, since the polarization rotation caused by the application of an electric field does not occur, even when the applied voltage is small, the variation in the piezoelectric characteristics can be kept low, and the reliability can be improved.

On the other hand, in the tetragonal perovskite-type PZT film, since the polarization axis direction is in the <001> direction, although the polarization axis direction and the electric field direction form an angle of about 54° due to the (111) plane orientation, However, by improving the (111) plane orientation, it is possible to keep the polarization axis at a constant angle with respect to the direction of the electric field. Therefore, at this time, the polarization rotation caused by the applied electric field does not occur, so the difference in piezoelectric characteristics can be suppressed low, and the reliability can be improved at the same time (for example, in a non-oriented PZT film, due to the The polarization axis of a specific crystallographic axis faces in various directions, so after an electric field is applied, the polarization axes face directions parallel to the electric field respectively. Therefore, piezoelectric properties have a high voltage dependence, especially when the applied voltage is small, The difference becomes large. Also, when the voltage is repeatedly applied, a time-dependent change occurs, causing a problem in terms of reliability.)

In addition, by making the first and second piezoelectric thin films of the piezoelectric laminated film an aggregate of columnar particles in continuous contact with each other, the average cross-sectional diameter of the columnar particles in the second piezoelectric thin film is larger than that of the first piezoelectric thin film. The average cross-sectional diameter of the columnar particles of the bulk thin film is such that the ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is greater than or equal to 20 and less than or equal to 60, and the performance index of the piezoelectric material can be obtained The piezoelectric laminated film with a very large piezoelectric constant can suppress the occurrence of film detachment even when it is driven with a high voltage to obtain a large actuator.

In addition, since a piezoelectric multilayer film with good orientation can be easily obtained without using an expensive MgO single crystal substrate, by using an inexpensive glass substrate, metal substrate, ceramic substrate, silicon ( Si) substrate, etc., can reduce the manufacturing cost.

In addition, even if the thickness of the piezoelectric laminated film is 1 μm or more, it is not necessary to repeat the same process several times as in the sol-gel state interchange method, and the piezoelectric laminated film can be easily formed by sputtering or the like. A decrease in yield is suppressed.

As described above, a piezoelectric element oriented on the (111) plane can be easily obtained. In addition, since the (111) plane is originally a plane that is easily oriented, the conditions for film formation are wide, the variation in piezoelectric characteristics is suppressed low, and the yield can be easily increased. Furthermore, since the (111) plane orientation degree is high, piezoelectric characteristics can be made high and voltage dependence can be made low.

According to a second invention, in the first invention, the columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of 40 nm or more and 70 nm or less, and a length of 5 nm or more and 100 nm or less.

According to a third invention, in the first invention, the columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of 60 nm or more and 200 nm or less, and a length of 2500 nm or more and 5000 nm or less.

According to the second and third inventions, it is possible to form a piezoelectric multilayer film with high piezoelectric characteristics, and to suppress the occurrence of film detachment even when the actuator is driven at a high voltage to obtain a large actuator displacement.

According to a fourth invention, in the first invention, the first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate. The (111) crystal orientation ratio of the first piezoelectric thin film is not less than 50% and not more than 80%. The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%.

In this way, it is possible to form a piezoelectric multilayer film with high piezoelectric characteristics, and at the same time, the variation in piezoelectric characteristics can be suppressed to be low, and the reliability can be improved.

According to a fifth invention, in the first invention, the chemical composition ratio of the piezoelectric laminate film is represented by Pb:Zr:Ti=(1+a):b:(1-b). The b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60. The Pb content of the first piezoelectric thin film is larger than the Pb content of the second piezoelectric thin film. The value a of the first piezoelectric thin film is not less than 0.05 and not more than 0.15. The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10.

In this way, by using lead zirconate titanate for the piezoelectric laminated film and making the content of zirconium 40 mol % or more and 60 mol % or less, it is possible to form a piezoelectric laminated film with high piezoelectric characteristics. Furthermore, by making the content of lead excessive compared with the stoichiometric structure, exceeding 0 and 15 mol % or less, the crystallinity of the piezoelectric laminated film can be improved and the piezoelectric constant can be increased. Furthermore, by making the content of excess lead equal to or less than 15 mol%, the withstand voltage can be improved, and a high-performance piezoelectric element can be obtained.

According to a sixth invention, in the first invention, the piezoelectric laminate film is formed by adding at least one of magnesium and manganese to lead zirconate titanate, and the added amount exceeds 0 and is equal to or less than 10 mol%.

In this way, the crystallinity of the piezoelectric multilayer film can be improved, and the piezoelectric characteristics can be further improved.

According to a seventh invention, in the first invention, the first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is a collection of columnar particles having an average cross-sectional diameter of 20 nm or more and 30 nm or less body.

In this way, the first electrode film can sufficiently withstand the temperature when each film of the piezoelectric element is formed by sputtering, etc., and at the same time, by controlling the average cross-sectional diameter of the first electrode film, it is possible to improve the adhesion to the substrate. properties, it is possible to reliably suppress film detachment during piezoelectric element manufacturing.

The eighth invention is aimed at such an inkjet head, including: a first electrode film, a piezoelectric laminate film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated. A piezoelectric element, a vibrating layer provided on the surface of the piezoelectric element on the side of the second electrode film, and a surface of the vibrating layer opposite to the second electrode film that is bonded to form a housing The pressure chamber part of the ink pressure chamber. The vibration layer is displaced in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film, and the ink in the pressure chamber is ejected.

Furthermore, the piezoelectric element of the present invention is the piezoelectric element of the first invention. In other words, the above-mentioned piezoelectric multilayer film is composed of a perovskite-type oxide preferentially oriented on the (111) plane of a rhombohedral system or a tetragonal system, and the above-mentioned first and second piezoelectric thin films are continuous with each other. An aggregate of contacting columnar particles, the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film, and the thickness of the piezoelectric laminated film is the same as that of the first piezoelectric thin film. 2. The ratio of the average cross-sectional diameters of the columnar particles of the piezoelectric thin film is 20 or more and 60 or less.

In this way, the first electrode film, the piezoelectric laminated film, the second electrode film, and the vibrating layer are sequentially formed on the substrate by sputtering or the like, and the liner is bonded to the vibrating layer after the pressure chamber member is bonded to the vibrating layer. By removing the bottom, an inkjet head having a piezoelectric element having the same structure as that of the first invention can be obtained, and the (111) plane orientation degree of the second piezoelectric thin film of the piezoelectric element can be 95% or more. Therefore, it is possible to obtain an inkjet head with less variation in ink discharge performance and excellent durability.

The ninth invention is aimed at such an inkjet head, including: a first electrode film, a piezoelectric laminate film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated. A piezoelectric element, a vibrating layer provided on the surface of the piezoelectric element on the side of the first electrode film, and a surface of the vibrating layer opposite to the first electrode film bonded to form a housing The pressure chamber part of the ink pressure chamber. The vibration layer is displaced in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film, and the ink in the pressure chamber is ejected.

Furthermore, the piezoelectric element of the present invention is the piezoelectric element of the first invention. In other words, the above-mentioned piezoelectric multilayer film is composed of a perovskite-type oxide preferentially oriented on the (111) plane of a rhombohedral system or a tetragonal system, and the above-mentioned first and second piezoelectric thin films are continuous with each other. An aggregate of contacting columnar particles, the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film, and the thickness of the piezoelectric laminated film is the same as that of the first piezoelectric thin film. 2. The ratio of the average cross-sectional diameters of the columnar particles of the piezoelectric thin film is 20 or more and 60 or less.

In this way, by using the pressure chamber member as a substrate and sequentially forming the vibration layer, the first electrode film, the piezoelectric laminate film, and the second electrode film thereon by sputtering or the like, it is possible to obtain the same advantages as those of the eighth invention. The effect of the inkjet head.

A tenth invention is an ink jet recording device comprising: the ink jet head according to the eighth invention; and a relative movement mechanism for relatively moving the ink jet head and the recording medium. When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording.

An eleventh invention is an inkjet recording device comprising: the inkjet head according to the ninth invention; and a relative movement mechanism for relatively moving the inkjet head and the recording medium. When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording.

According to the tenth and eleventh inventions, an inkjet recording device excellent in printing performance and durability can be obtained relatively easily.

The twelfth invention is aimed at such an angular velocity sensor, comprising a substrate having a fixed portion and at least a pair of vibrating portions extending from the fixed portion in a predetermined direction, and at least each vibrating portion of the substrate is provided with a first A piezoelectric element in which an electrode film, a piezoelectric laminated film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated, and the second electrode film on each of the vibrating parts is patterned as At least one driving electrode for vibrating the vibrating portion in its width direction, and at least one detecting electrode for detecting deformation in the thickness direction of the vibrating portion.

Furthermore, the piezoelectric element of the present invention is the piezoelectric element of the first invention. In other words, the above-mentioned piezoelectric multilayer film is composed of a perovskite-type oxide preferentially oriented on the (111) plane of a rhombohedral system or a tetragonal system, and the above-mentioned first and second piezoelectric thin films are continuous with each other. An aggregate of contacting columnar particles, the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film, and the thickness of the piezoelectric laminated film is the same as that of the first piezoelectric thin film. 2. The ratio of the average cross-sectional diameters of the columnar particles of the piezoelectric thin film is 20 or more and 60 or less.

In this way, by applying a voltage between the driving electrode of the second electrode film and the first electrode film, each vibrating portion of the substrate is vibrated in its width direction, and when the vibration occurs due to Coriolis force, the vibrating portion When deformed in the thickness direction, a voltage is generated between the detection electrode of the second electrode film and the first electrode film, and the angular velocity can be detected from the magnitude of the voltage (Coriolis force). And, since the portion (vibration portion) that detects the angular velocity is constituted by the piezoelectric body element having the same structure as the first invention, the piezoelectric constant can be increased by about 40 times compared with the conventional angular velocity sensor using a crystal, and it is possible to Achieve a considerable degree of miniaturization.

In addition, even if mass-produced in the industry, it is possible to obtain an angular velocity sensor with good reproducibility of characteristics, little variation, good withstand voltage, and good reliability.

Furthermore, since the piezoelectric multilayer film is oriented on the (111) plane which is the polarization axis, it is less likely to be affected by the expansion coefficient of the substrate.

According to a 13th invention, in the 12th invention, the columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of 40 nm or more and 70 nm or less, and a length of 5 nm or more and 100 nm or less.

According to a 14th invention, in the 12th invention, the columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of 60 nm or more and 200 nm or less, and a length of 2500 nm or more and 5000 nm or less.

According to the thirteenth and fourteenth inventions, it is possible to form a piezoelectric multilayer film with high piezoelectric characteristics, and it is possible to improve the sensitivity of the sensor and at the same time realize miniaturization.

According to a fifteenth invention, in the twelfth invention, the first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate. The (111) crystal orientation ratio of the first piezoelectric thin film is not less than 50% and not more than 80%. The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%.

In this way, it is possible to form a piezoelectric multilayer film having high piezoelectric characteristics, and at the same time, it is possible to suppress variations in piezoelectric characteristics and improve reliability.

In the sixteenth invention, in the twelfth invention, the chemical composition ratio of the piezoelectric laminated film is represented by [Pb]:[Zr]:[Ti]=(1+a):b:(1-b). The b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60. The Pb content of the first piezoelectric thin film is larger than the Pb content of the second piezoelectric thin film. The value a of the first piezoelectric thin film is not less than 0.05 and not more than 0.15. The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10.

In this way, by using lead zirconate titanate for the piezoelectric laminated film and making the content of zirconium 40 mol % or more and 60 mol % or less, it is possible to form a piezoelectric laminated film with high piezoelectric characteristics. Furthermore, by making the content of lead excessive compared with the stoichiometric structure, exceeding 0 and 15 mol % or less, the crystallinity of the piezoelectric laminated film can be improved and the piezoelectric constant can be increased. Furthermore, by making the content of excess lead equal to or less than 15 mol%, the withstand voltage can be improved, and a high-performance piezoelectric element can be obtained.

In the seventeenth invention, in the twelfth invention, the piezoelectric laminate film is formed by adding at least one of magnesium and manganese to lead zirconate titanate, and the added amount exceeds 0 and is equal to or less than 10 mol%.

In this way, the crystallinity of the piezoelectric multilayer film can be improved, and the piezoelectric characteristics can be further improved.

According to an eighteenth invention, in the twelfth invention, the first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is a collection of columnar particles having an average cross-sectional diameter of 20 nm or more and 30 nm or less body.

In this way, the first electrode film can sufficiently withstand the temperature when forming the individual films of the piezoelectric element by sputtering, etc., and at the same time, by controlling the average cross-sectional diameter of the first electrode film, it is possible to improve the adhesion to the substrate. properties, it is possible to reliably suppress film detachment during piezoelectric element manufacturing.

According to a nineteenth invention, in the twelfth invention, the substrate is made of silicon (Si).

In this way, manufacturing cost can be reduced.

The twentieth invention is directed to a method of manufacturing a piezoelectric element.

Moreover, the present invention includes: a step of forming a first electrode film on a substrate by a sputtering method; continuously forming a perovskite-type oxide film of a rhombohedral system or a tetragonal system on the first electrode film by a sputtering method. a step of forming a piezoelectric laminate film from the first and second piezoelectric thin films; and a step of forming a second electrode film on the piezoelectric laminate film. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on the (111) plane.

In this way, it is possible to easily manufacture a piezoelectric element having the same effect as that of the first invention.

The 21st invention is aimed at the manufacturing method of the inkjet head.

Moreover, the present invention includes: a step of forming a first electrode film on a substrate by a sputtering method; continuously forming a perovskite-type oxide film of a rhombohedral system or a tetragonal system on the first electrode film by a sputtering method. The process of forming the first and second piezoelectric thin films composed of materials, forming a piezoelectric laminate film; the process of forming a second electrode film on the above piezoelectric laminate film; the process of forming a vibration layer on the above second electrode film ; a step of bonding a pressure chamber member for forming a pressure chamber on the surface of the vibrating layer opposite to the second electrode film; and a step of removing the substrate after the bonding step. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on the (111) plane.

In this way, an inkjet head having the same operation and effect as the eighth invention can be easily manufactured.

The 22nd invention is aimed at the manufacturing method of the inkjet head.

Furthermore, the present invention includes: a step of forming a vibration layer on a pressure chamber substrate forming a pressure chamber; a step of forming a first electrode film on the vibration layer by a sputtering method; and forming a first electrode film on the first electrode film by a sputtering method. The process of forming the first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides successively to form a piezoelectric laminated film; forming the second piezoelectric laminated film on the piezoelectric laminated film a process of electrode film; and a process of forming a pressure chamber on the pressure chamber substrate. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on the (111) plane.

In this way, it is possible to easily manufacture an inkjet head having the same operation and effect as the ninth invention.

The 23rd invention is aimed at the manufacturing method of an angular velocity sensor.

Moreover, the present invention includes: a step of forming a first electrode film on a substrate by a sputtering method; continuously forming a perovskite-type oxide film of a rhombohedral system or a tetragonal system on the first electrode film by a sputtering method. The process of forming the first and second piezoelectric thin films composed of materials, forming a piezoelectric laminate film; the process of forming a second electrode film on the above piezoelectric laminate film; patterning the above second electrode film to form drive electrodes and A step of detecting electrodes; a step of patterning the piezoelectric multilayer film and the first electrode film; and a step of patterning the substrate to form a fixed portion and a vibrating portion. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on the (111) plane.

In this way, it is possible to easily manufacture an angular velocity sensor having the same operation and effect as the twelfth invention.

Furthermore, in order to achieve the above object, in inventions other than the present invention, an orientation control film is formed on an electrode film made of a noble metal, and a two-layer piezoelectric multilayer film is formed on the orientation control film. At this time, by first forming an orientation control film preferentially oriented to the (111) plane, and then forming a two-layered piezoelectric laminate film thereon, a piezoelectric laminate having a high degree of (111) plane orientation as a whole is formed. membrane.

Specifically, the twenty-fourth invention in the first invention further includes an orientation control film provided between the first electrode film and the first piezoelectric thin film. The above-mentioned orientation control film is composed of a perovskite-type oxide that is preferentially oriented to the (111) plane of the cubic system or the tetragonal system.

In other words, it is aimed at a piezoelectric element that includes a first electrode film, an orientation control film provided on the first electrode film, and a first piezoelectric element provided on the orientation control film. A piezoelectric laminated film composed of a thin film and a second piezoelectric thin film provided on the first piezoelectric thin film, and a second electrode film provided on the piezoelectric laminated film. Furthermore, in the present invention, the above-mentioned orientation control film is composed of a perovskite-type oxide preferentially oriented to the (111) plane of the cubic system or tetragonal system, and the above-mentioned piezoelectric multilayer film is composed of the Composed of perovskite-type oxides on the (111) plane of a tetragonal system, the first and second piezoelectric thin films are aggregates of columnar particles that are in continuous contact with each other, and the columnar particles of the second piezoelectric thin film are The average cross-sectional diameter is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film, and the ratio of the thickness of the piezoelectric laminate film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is not less than 20 and not more than 60. .

In this way, by providing an orientation control film of a perovskite-type oxide preferentially oriented to the (111) plane of the cubic or tetragonal crystal on the first electrode film, it is possible to make the The piezoelectric multilayer film composed of a perovskite-type oxide is preferentially oriented on the same (111) plane. Therefore, the variation in piezoelectric characteristics can be kept low, and the reliability can be improved. In other words, since this piezoelectric element is used to apply an electric field in a direction perpendicular to the film surface of this piezoelectric laminated film, especially in a rhombohedral perovskite-type PZT film, due to (111) By aligning the plane so that the <111> polarization axis direction is parallel to the direction of the electric field, a large piezoelectric characteristic can be obtained. In addition, since the polarization rotation caused by the application of an electric field does not occur, even when the applied voltage is small, the variation in the piezoelectric characteristics can be kept low and the reliability can be improved.

In the tetragonal perovskite PZT film, since the direction of the polarization axis is in the <001> direction, although the direction of the polarization axis forms an angle of about 54° with the direction of the electric field due to the (111) plane orientation, but by By improving the (111) plane orientation, the angle between the polarization axis and the direction of the electric field can always be kept constant. Therefore, at this time, the polarization rotation caused by the applied electric field does not occur, so the difference in piezoelectric characteristics can be suppressed low, and the reliability can be improved at the same time (for example, in a non-oriented PZT film, due to the The polarization axis of a specific crystallographic axis faces in various directions, so after an electric field is applied, the polarization axes face directions parallel to the electric field. Therefore, the piezoelectric characteristics have a high voltage dependence, especially when the applied voltage is small, its The difference becomes large. Also, when the voltage is repeatedly applied, a time-dependent change occurs, which causes a problem in terms of reliability).

In addition, by making the first and second piezoelectric thin films of the piezoelectric laminated film an aggregate of columnar particles continuously in contact with each other, the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is larger than that of the first piezoelectric thin film. The average cross-sectional diameter of the columnar particles of the bulk thin film is such that the ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is greater than or equal to 20 and less than or equal to 60, and a piezoelectric constant with a very large piezoelectric constant can be obtained. The electro-stacked film can suppress the occurrence of film detachment even when it is driven with a high voltage in order to obtain a large actuator displacement.

In addition, since a piezoelectric multilayer film with good orientation can be easily obtained without using an expensive MgO single crystal substrate, by using an inexpensive glass substrate, metal substrate, ceramic substrate, silicon ( Si) substrate, etc., can reduce the manufacturing cost.

In addition, even if the thickness of the piezoelectric laminated film is 1 μm or more, it is not necessary to repeat the same process several times as in the sol-gel state interchange method, and the piezoelectric laminated film can be easily formed by sputtering or the like. A decrease in yield is suppressed.

As described above, a piezoelectric element oriented on the (111) plane can be easily obtained. In addition, since the (111) plane is originally a plane that is easily oriented, the conditions for film formation are wide, the variation in piezoelectric characteristics is suppressed low, and the yield can be easily increased. Furthermore, since the (111) plane orientation degree is high, piezoelectric characteristics can be made high and voltage dependence can be made low.

According to a 25th invention, in the 24th invention, the columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of 40 nm or more and 70 nm or less, and a length of 5 nm or more and 100 nm or less.

According to a 26th invention, in the 24th invention, the columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of 60 nm or more and 200 nm or less, and a length of 2500 nm or more and 5000 nm or less.

According to the twenty-fifth and twenty-sixth inventions, it is possible to form a piezoelectric multilayer film with high piezoelectric characteristics, and to suppress the occurrence of film detachment even when the actuator is driven at a high voltage to obtain a large actuator displacement.

According to a twenty-seventh invention, in the twenty-fourth invention, the first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate. The (111) crystal orientation ratio of the first piezoelectric thin film is not less than 50% and not more than 80%. The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%.

In this way, it is possible to form a piezoelectric multilayer film with high piezoelectric characteristics, suppress variations in piezoelectric characteristics to a low level, and improve reliability.

In the 28th invention, in the 24th invention, the chemical composition ratio of the piezoelectric laminated film is represented by [Pb]:[Zr]:[Ti]=(1+a):b:(1-b). The b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60. The Pb content of the first piezoelectric thin film is larger than the Pb content of the second piezoelectric thin film. The value a of the first piezoelectric thin film is not less than 0.05 and not more than 0.15. The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10.

In this way, by using lead zirconate titanate for the piezoelectric laminated film and making the content of zirconium 40 mol % or more and 60 mol % or less, it is possible to form a piezoelectric laminated film with high piezoelectric characteristics. Furthermore, by making the content of lead excessive compared with the stoichiometric structure, exceeding 0 and equal to or less than 15 mol%, the crystallinity of the piezoelectric laminated film can be improved and the piezoelectric constant can be increased. Furthermore, by making the content of excess lead equal to or less than 15 mol%, the withstand voltage can be improved, and a high-performance piezoelectric element can be obtained.

In the 29th invention, in the 24th invention, the orientation control film is composed of perovskite-type lead lanthanum zirconate titanate oxide as a main component, and the (111) crystal orientation ratio of the orientation control film is 50% or more.

In the 30th invention, in the 24th invention, the chemical composition ratio of the above-mentioned alignment control film is [Pb]:[La]:[Zr]:[Ti]=x×(1-z):z:y:(1- y) said. The above x value is greater than or equal to 1.0 and less than or equal to 1.20. The above y value is greater than or equal to 0 and less than or equal to 0.20. The above-mentioned z value is more than 0 and less than or equal to 0.30.

In this way, the orientation control film can be more easily oriented to (111) plane, and the orientation of the piezoelectric laminated film can be improved. Furthermore, by making the content of zirconium 20 mol% or less, it becomes difficult to form a low crystallinity layer composed of zirconium (Zr) oxide in the initial stage of crystal growth. In addition, by making the content of lead excessive compared with the stoichiometric structure, exceeding 0 and equal to or less than 20 mol%, the decrease in the crystallinity of the orientation control film can be reliably suppressed, so that the piezoelectric body formed thereon can be laminated. The crystallinity of the film is improved. Therefore, the crystallinity and orientation of the piezoelectric multilayer film can be improved reliably, and the piezoelectric characteristics can be further improved.

In the 31st invention, in the 24th invention, the orientation control film is formed by adding at least one of magnesium and manganese to lead lanthanum zirconate titanate in an amount of more than 0 and less than or equal to 10 mol%.

According to the 32nd invention, in the 24th invention, the above-mentioned piezoelectric laminated film is formed by adding at least one of magnesium and manganese to lead zirconate titanate, and the added amount exceeds 0 and is equal to or less than 10 mol % of the piezoelectric body. element.

According to the 31st and 32nd inventions, the crystallinity of the orientation control film and the piezoelectric multilayer film can be improved, and the piezoelectric characteristics can be further improved.

In the 33rd invention, in the 24th invention, the first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is a collection of columnar particles having an average cross-sectional diameter of 20 nm or more and 30 nm or less body.

In this way, the first electrode film can sufficiently withstand the temperature when forming the individual films of the piezoelectric element by sputtering, etc., and at the same time, by controlling the average cross-sectional diameter of the first electrode film, it is possible to improve the adhesion to the substrate. properties, it is possible to reliably suppress film detachment during piezoelectric element manufacturing.

The 34th invention is aimed at an inkjet head and includes: a first electrode film, an orientation control film, a piezoelectric laminate film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated a piezoelectric element; a vibrating layer provided on the surface of the piezoelectric element on the side of the second electrode film; A pressure chamber part of a pressure chamber that holds ink. The vibration layer is displaced in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film, and the ink in the pressure chamber is ejected.

Furthermore, the piezoelectric element of the present invention is the piezoelectric element of the twenty-fourth invention. In other words, the orientation control film is composed of a perovskite oxide preferentially oriented to the (111) plane of a cubic or tetragonal system, and the piezoelectric laminate film is composed of a perovskite oxide preferentially oriented to a rhombohedral or tetragonal system. (111)-based perovskite-type oxide, the first and second piezoelectric thin films are aggregates of columnar particles that are in continuous contact with each other, and the average cross-section of the columnar particles in the second piezoelectric thin film is The diameter is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film, and the ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is greater than or equal to 20 and less than or equal to 60.

In this way, the first electrode film, the orientation control film, the piezoelectric laminate film, the second electrode film, and the vibration layer are sequentially formed on the substrate by sputtering or the like, and the pressure chamber member is bonded to the vibration layer. After removing the substrate, an inkjet head having a piezoelectric element having the same structure as that of the twenty-fourth invention can be obtained, and the (111) plane orientation degree of the second piezoelectric thin film of the piezoelectric element can be made equal to or greater than 95%. Therefore, it is possible to obtain an inkjet head with less variation in ink discharge performance and excellent durability.

The thirty-fifth invention is aimed at such an inkjet head, and includes sequentially laminating a first electrode film, an orientation control film, a piezoelectric laminate film composed of first and second piezoelectric thin films, and a second electrode film. The resulting piezoelectric element is provided on the vibration layer of the piezoelectric element on the side of the first electrode film, and is bonded to the surface of the vibration layer opposite to the first electrode film and formed The pressure chamber part that contains the pressure chamber that holds the ink. The vibration layer is displaced in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film, and the ink in the pressure chamber is ejected.

Furthermore, the piezoelectric element of the present invention is the piezoelectric element of the twenty-fourth invention. In other words, the orientation control film is composed of a perovskite oxide preferentially oriented to the (111) plane of a cubic or tetragonal system, and the piezoelectric laminate film is composed of a perovskite oxide preferentially oriented to a rhombohedral or tetragonal system. (111)-based perovskite-type oxide, the first and second piezoelectric thin films are aggregates of columnar particles that are in continuous contact with each other, and the average cross-section of the columnar particles in the second piezoelectric thin film is The diameter is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film, and the ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is greater than or equal to 20 and less than or equal to 60.

In this way, by using the pressure chamber member as a substrate and sequentially forming the vibration layer, the first electrode film, the orientation control film, the piezoelectric laminate film, and the second electrode film thereon by sputtering or the like, it is possible to obtain 34 Invention of an inkjet head having the same effect.

The thirty-sixth invention is directed to such an inkjet recording apparatus, comprising: an inkjet head; and a relative movement mechanism for relatively moving the inkjet head and a recording medium. When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording.

Moreover, the said inkjet head of this invention is the inkjet head of 34th invention.

The thirty-seventh invention is directed to such an inkjet recording device, and includes: an inkjet head; and a relative movement mechanism for relatively moving the inkjet head and a recording medium. When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording.

Furthermore, the above-mentioned inkjet head of the present invention is the inkjet head of the thirty-fifth invention.

According to the thirty-sixth and thirty-seventh inventions, an inkjet recording device excellent in printing performance and durability can be easily obtained.

The thirty-eighth invention is directed to such an angular velocity sensor, which includes a substrate having a fixed portion and at least a pair of vibrating portions extending from the fixed portion in a predetermined direction, and a first electrode is provided on at least each vibrating portion of the substrate. film, an orientation control film, a piezoelectric laminated film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated. At least one driving electrode for vibrating the vibrating portion in its width direction and at least one detecting electrode for detecting deformation in the thickness direction of the vibrating portion are patterned.

Furthermore, the piezoelectric element of the present invention is the piezoelectric element of the twenty-fourth invention. In other words, the orientation control film is composed of a perovskite oxide preferentially oriented to the (111) plane of a cubic or tetragonal system, and the piezoelectric laminate film is composed of a perovskite oxide preferentially oriented to a rhombohedral or tetragonal system. (111)-based perovskite-type oxide, the first and second piezoelectric thin films are aggregates of columnar particles that are in continuous contact with each other, and the average cross-section of the columnar particles in the second piezoelectric thin film is The diameter is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film, and the ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is greater than or equal to 20 and less than or equal to 60.

In this way, by applying a voltage between the driving electrode of the second electrode film and the first electrode film, each vibrating portion of the substrate is vibrated in its width direction, and when the vibration occurs due to Coriolis force, the vibrating portion When deformed in the thickness direction, a voltage is generated between the detection electrode of the second electrode film and the first electrode film, and the angular velocity can be detected from the magnitude of the voltage (Coriolis force). And, since the portion (vibration portion) that detects the angular velocity is constituted by the piezoelectric body element having the same structure as that of the twenty-fourth invention, the piezoelectric constant can be increased by about 40 times compared with the conventional angular velocity sensor using a crystal, and it is possible to Achieve a considerable degree of miniaturization.

In addition, even if mass-produced in the industry, it is possible to obtain an angular velocity sensor with good characteristic reproducibility, little variation, good withstand voltage, and good reliability.

Furthermore, since the piezoelectric multilayer film is oriented on the (111) plane which is the polarization axis, it is less likely to be affected by the expansion coefficient of the substrate.

According to a 39th invention, in the 38th invention, the columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of 40 nm or more and 70 nm or less, and a length of 5 nm or more and 100 nm or less.

According to a 40th invention, in the 38th invention, the columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of 60 nm or more and 200 nm or less, and a length of 2500 nm or more and 5000 nm or less.

According to the thirty-ninth and forty-ninth inventions, it is possible to form a piezoelectric multilayer film having high piezoelectric characteristics, and it is possible to improve the sensitivity of the sensor and achieve miniaturization.

In the 41st invention, in the 38th invention, the first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate. The (111) crystal orientation ratio of the first piezoelectric thin film is not less than 50% and not more than 80%. The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%.

In this way, it is possible to form a piezoelectric multilayer film with high piezoelectric characteristics, suppress variations in piezoelectric characteristics to a low level, and improve reliability.

In the 42nd invention, in the 38th invention, the chemical composition ratio of the piezoelectric laminated film is represented by [Pb]:[Zr]:[Ti]=(1+a):b:(1-b). The b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60. The Pb content of the first piezoelectric thin film is larger than the Pb content of the second piezoelectric thin film. The value a of the first piezoelectric thin film is not less than 0.05 and not more than 0.15. The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10.

In this way, by using lead zirconate titanate in the piezoelectric laminated film and making the content of zirconium 40 mol % or more and 60 mol % or less, it is possible to form a piezoelectric laminated film with high piezoelectric characteristics. Furthermore, by making the content of lead excessive compared with the stoichiometric structure, exceeding 0 and equal to or less than 15 mol%, the crystallinity of the piezoelectric laminated film can be improved and the piezoelectric constant can be increased. Furthermore, by setting the content of excess lead to 15 mol% or less, the withstand voltage can be improved, and a high-performance piezoelectric element can be obtained.

In the 43rd invention, in the 38th invention, the orientation control film is composed of an oxide mainly composed of perovskite-type lead lanthanum zirconate titanate. The (111) crystal orientation ratio of the above-mentioned orientation control film is equal to or greater than 50%.

In the 44th invention, in the 38th invention, the chemical composition ratio of the alignment control film is represented by Pb:La:Zr:Ti=x×(1-z):z:y:(1-y). The above x value is greater than or equal to 1.0 and less than or equal to 1.20. The above y value is greater than or equal to 0 and less than or equal to 0.20. The above-mentioned z value is more than 0 and less than or equal to 0.30.

According to the 43rd and 44th inventions, by using lead lanthanum zirconate titanate (PLZT, zirconium content is 0, that is, containing lead lanthanum titanate (PLT)) in the orientation control film, it is possible to obtain 30 inventions have the same effect.

In the 45th invention, in the 38th invention, the orientation control film is formed by adding at least one of magnesium and manganese to lead lanthanum zirconate titanate in an amount of more than 0 and less than or equal to 10 mol%.

According to a 46th invention, in the 38th invention, the piezoelectric laminate film is formed by adding at least one of magnesium and manganese to lead zirconate titanate in an amount of more than 0 and less than or equal to 10 mol%.

According to the forty-fifth and forty-sixth inventions, the crystallinity of the orientation control film and the piezoelectric multilayer film can be improved, and the piezoelectric characteristics can be further improved.

In the 47th invention, in the 38th invention, the first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is a collection of columnar particles having an average cross-sectional diameter of 20 nm or more and 30 nm or less body.

In this way, the first electrode film can sufficiently withstand the temperature when forming the individual films of the piezoelectric element by sputtering, etc., and at the same time, by controlling the average cross-sectional diameter of the first electrode film, it is possible to improve the adhesion to the substrate. properties, it is possible to reliably suppress film detachment during piezoelectric element manufacturing.

According to a 48th invention, in the 38th invention, the above-mentioned substrate is made of silicon (Si).

In this way, manufacturing cost can be reduced.

The forty-ninth invention is directed to a method of manufacturing a piezoelectric element.

Furthermore, the present invention includes: a step of forming a first electrode film on a substrate by a sputtering method; The process of the orientation control film; the first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides are continuously formed on the above orientation control film by sputtering to form piezoelectric a step of forming a bulk laminated film; and a step of forming a second electrode film on the piezoelectric laminated film. The step of forming the above-mentioned orientation control film includes a step of preferentially orienting the orientation control film on the (111) plane. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on a (111) plane via the orientation control film.

In this way, it is possible to easily manufacture a piezoelectric element having the same function and effect as that of the twenty-fourth invention.

The fiftieth invention is directed to a method of manufacturing an inkjet head.

Furthermore, the present invention includes: a step of forming a first electrode film on a substrate by a sputtering method; The process of the orientation control film; the first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides are continuously formed on the above orientation control film by sputtering to form piezoelectric a step of forming a bulk laminated film; a step of forming a second electrode film on the piezoelectric laminated film; a step of forming a vibrating layer on the second electrode film; bonding a pressure chamber member for forming a pressure chamber to the vibrating layer a step on the surface opposite to the second electrode film; and a step of removing the substrate after the bonding step. The step of forming the above-mentioned orientation control film includes a step of preferentially orienting the orientation control film on the (111) plane. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on a (111) plane via the orientation control film.

In this way, an inkjet head having the same function and effect as that of the 34th invention can be easily manufactured.

The fifty-first invention is directed to a method of manufacturing an inkjet head.

Furthermore, the present invention includes: a step of forming a vibration layer on a pressure chamber substrate forming a pressure chamber; a step of forming a first electrode film on the vibration layer by a sputtering method; and forming a first electrode film on the first electrode film by a sputtering method. A process of forming an orientation control film composed of a cubic or tetragonal perovskite oxide; continuously forming a rhombohedral or tetragonal perovskite oxide on the orientation control film by sputtering A step of forming the first and second piezoelectric thin films made of oxide, forming a piezoelectric laminate film; a step of forming a second electrode film on the piezoelectric laminate film; and forming a pressure chamber on the pressure chamber substrate process. The step of forming the above-mentioned orientation control film includes a step of preferentially orienting the orientation control film on the (111) plane. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on a (111) plane via the orientation control film.

In this way, it is possible to easily manufacture an inkjet head having the same effect as that of the thirty-fifth invention.

The fifty-second invention is directed to a method of manufacturing an angular velocity sensor.

Furthermore, the present invention includes: a step of forming a first electrode film on a substrate by a sputtering method; The process of the orientation control film; the first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides are continuously formed on the above orientation control film by sputtering to form piezoelectric a step of forming a bulk laminated film; a step of forming a second electrode film on the piezoelectric laminated film; a step of patterning the second electrode film to form a driving electrode and a detection electrode; forming the piezoelectric laminated film, the orientation control a step of patterning the film and the first electrode film; and a step of patterning the substrate to form a fixed part and a vibrating part. The step of forming the above-mentioned orientation control film includes a step of preferentially orienting the orientation control film on the (111) plane. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on a (111) plane via the orientation control film.

In this way, it is possible to easily manufacture an angular velocity sensor having the same operation and effect as that of the thirty-eighth invention.

(effect of invention)

According to the piezoelectric element of the present invention, large piezoelectric displacement characteristics and high durability can be realized.

According to the manufacturing method of the piezoelectric element of the present invention, it is possible to easily mass-produce piezoelectric elements having large piezoelectric displacement characteristics and high durability. Therefore, even if it is mass-produced industrially, it is possible to obtain a piezoelectric element having good piezoelectric characteristics reproducibility, little variation, good withstand voltage, and high reliability.

According to the inkjet head and the inkjet recording device of the present invention, it is possible to reduce variations in ink discharge performance and achieve high durability.

According to the angular velocity sensor of the present invention, miniaturization and high dimensional accuracy can be realized, and even if it is mass-produced industrially, it is possible to obtain an angular velocity sensor with good piezoelectric characteristics reproducibility, little variation, good withstand voltage and reliability .

A brief description of the drawings

FIG. 1 is a perspective view of a piezoelectric element according to Embodiment 1 of the present invention.

FIG. 2 is a process diagram showing a method of manufacturing the piezoelectric element according to Embodiment 1. FIG.

3 is a schematic diagram of a film structure of a piezoelectric laminate film according to Embodiment 1. FIG.

4 is an electron micrograph showing an enlarged cross-section of a piezoelectric laminate film according to the first example of Embodiment 1. FIG.

5 is a graph showing the displacement amount of the tip of the piezoelectric element moving up and down in the Z direction when a voltage having a frequency of 2 kHz is applied in the first example of the first embodiment.

FIG. 6 is a schematic configuration diagram of an inkjet head according to Embodiment 2. FIG.

FIG. 7 is an exploded perspective view of a part of the ink discharge element according to Embodiment 2. FIG.

FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7 .

9 is a process diagram showing a part of the manufacturing method of the actuator unit according to the sixth example of the second embodiment.

10 is a process diagram showing a part of the method of manufacturing the actuator unit according to the sixth example of the second embodiment.

11 is a view corresponding to the sectional view taken along line VIII-VIII in FIG. 7 of an actuator unit according to a seventh example of the second embodiment.

12 is a process diagram showing a part of the manufacturing method of the actuator unit according to the seventh example of the second embodiment.

13 is a process diagram showing a part of the manufacturing method of the actuator unit according to the seventh example of the second embodiment.

14 is a schematic perspective view of an inkjet recording device according to Embodiment 3. FIG.

FIG. 15 is a schematic diagram of an angular velocity sensor according to Embodiment 4. FIG.

FIG. 16 is a cross-sectional view of an angular velocity sensor according to Embodiment 4. FIG.

FIG. 17 is a process diagram showing a method of manufacturing the angular velocity sensor according to Embodiment 4. FIG.

FIG. 18 is a schematic diagram showing a method of manufacturing the angular velocity sensor of Embodiment 4. FIG.

FIG. 19 is a schematic diagram of a conventional angular velocity sensor.

FIG. 20 is a perspective view of a piezoelectric element according to Embodiment 5. FIG.

21 is a process diagram showing a method of manufacturing a piezoelectric element according to Embodiment 5. FIG.

22 is a schematic diagram of a film structure of a piezoelectric laminate film according to Embodiment 5. FIG.

23 is an electron micrograph showing an enlarged cross-section of a piezoelectric laminate film according to an eighth example of the fifth embodiment.

24 is a graph showing the displacement amount of the tip of the piezoelectric element moving up and down in the Z direction when a voltage having a frequency of 2 kHz is applied in the eighth example of the fifth embodiment.

25 is a view corresponding to the sectional view taken along line VIII-VIII in FIG. 7 of the actuator unit according to the thirteenth example of the sixth embodiment.

26 is a process diagram showing a part of the manufacturing method of the actuator unit according to the thirteenth example of the sixth embodiment.

27 is a process diagram showing a part of the method of manufacturing the actuator unit according to the thirteenth example of the sixth embodiment.

FIG. 28 is a view corresponding to the sectional view taken along line VIII-VIII in FIG. 7 of the actuator unit according to the fourteenth example of the sixth embodiment.

29 is a process diagram showing a part of the manufacturing method of the actuator unit according to the fourteenth example of the sixth embodiment.

30 is a process diagram showing a part of the manufacturing method of the actuator unit according to the fourteenth example of the sixth embodiment.

FIG. 31 is a schematic diagram of an angular velocity sensor according to Embodiment 8. FIG.

FIG. 32 is a cross-sectional view of an angular velocity sensor according to Embodiment 8. FIG.

33 is a process diagram showing a method of manufacturing the angular velocity sensor according to the eighth embodiment.

(explanation of symbols)

1, 51-substrate; 2, 52-first electrode film; 3, 41-orientation control film; 4, 42-first piezoelectric film; 5, 43-second piezoelectric film; 6, 44- 2nd electrode film; 10-piezoelectric laminated film; 20-piezoelectric element; 201-inkjet head; 202-ink discharge element; 32-pressure chamber; 33-individual electrode; 38-nozzle hole; 45-vibration Body layer; 58-pressure chamber parts (pressure chamber parts); 81-inkjet recording device; 82-recording medium; 83-carriage shaft (relative movement mechanism); 84-carriage part (relative movement mechanism) ; 85-roller (roller) (relative movement mechanism); 400-angular velocity sensor; 500-substrate; 500a-fixed part; 500b-vibrating part; 502-first electrode film; Piezoelectric thin film; 505-second piezoelectric thin film; 506-second electrode film; 507-driving electrode; 508-detection electrode.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)

FIG. 1 is a perspective view of a piezoelectric element 20 according to Embodiment 1 of the present invention. As shown in FIG. 1 , the piezoelectric element 20 includes: a rectangular plate-shaped substrate 1 having a length of 15.0 mm, a thickness of 0.40 mm, and a width of 3.0 mm; and a laminate 11 disposed on the substrate 1 . This substrate 1 functions as a vibrating plate that has an effect of preventing expansion and contraction due to the piezoelectric effect of the laminated body 11 . The piezoelectric body element 20 has a width of 3.0 mm. One end (the left end in FIG. 1 ) of the piezoelectric body element 20 with a width of 3.0 mm and a length of 3.0 mm was fixed to a stainless steel support substrate 7 with a thickness of 1.0 mm (the left end in FIG. 1 ) with an epoxy-based adhesive 8. 3.0 mm, and the depth is 10.0 mm), therefore, the piezoelectric body element 20 constitutes a beam with a single side.

A first electrode film 2 is provided on a substrate 1 . On the rest of the first electrode film 2 except one end (the left end in FIG. 1 ) (that is, the first electrode film 2 has a width of 3.0 mm and a length of 12.0 mm), there are 111) A piezoelectric multilayer film 10 composed of a lead zirconate titanate (hereinafter, PZT) oxide thin film having a perovskite crystal structure with preferential crystal orientation. The piezoelectric laminated film 10 is composed of a first piezoelectric thin film 4 and a second piezoelectric thin film 5 provided on the first piezoelectric thin film 4 . The crystal orientation of the second piezoelectric thin film 5 is controlled by the first piezoelectric thin film 4 . The second electrode film 6 having a thickness of 100 nm is provided on the piezoelectric multilayer film 10 . Metal lead wires 9a, 9b each having a thickness of 0.1 mm are connected to the first and second electrode films 2, 6, respectively. In addition, as shown in FIG. 1 , the laminated body 11 is composed of the first electrode film 2 , the piezoelectric laminated film 10 , and the second electrode film 6 .

The features of this embodiment will be described below.

The piezoelectric multilayer film 10 is composed of a perovskite-type oxide preferentially oriented on the (111) plane of the rhombohedral system or the tetragonal system. The first and second piezoelectric thin films 4 and 5 are aggregates of columnar particles that are in continuous contact with each other (see FIG. 3 ). The average cross-sectional diameter of the columnar particles of the second piezoelectric thin film 5 is larger than the average cross-sectional diameter (average particle diameter, average diameter) of the columnar particles of the first piezoelectric thin film 4 . The ratio of the thickness of the piezoelectric laminated film 10 to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film 5 is 20 or more and 60 or less.

Preferably, the columnar particles of the first piezoelectric thin film 4 have an average cross-sectional diameter of not less than 40 nm and not more than 70 nm, and a length of not less than 5 nm and not more than 100 nm. Preferably, the columnar particles of the second piezoelectric thin film 5 have an average cross-sectional diameter of not less than 60 nm and not more than 200 nm, and a length of not less than 2500 nm and not more than 5000 nm.

Preferably, the first and second piezoelectric thin films 4 and 5 are composed of oxides mainly composed of perovskite-type lead zirconate titanate, and the (111) crystal orientation ratio of the first piezoelectric thin film 4 is equal to or greater than 50. % is less than or equal to 80%, and the (111) crystal orientation ratio of the second piezoelectric thin film 5 is greater than or equal to 95% and less than or equal to 100%.

The chemical composition ratio of the piezoelectric laminated film 10 is represented by Pb:Zr:Ti=(1+a):b:(1-b), and the b value of the first and second piezoelectric thin films 4 and 5 is preferably The same value of 0.40 or less and 0.60 or more, the Pb content of the first piezoelectric thin film 4 is greater than the Pb content of the second piezoelectric thin film 5, and the a value of the first piezoelectric thin film 4 is greater than or equal to 0.05 and less than or equal to 0.15, and the a value of the second piezoelectric thin film 5 is greater than or equal to 0 and less than or equal to 0.10. Alternatively, it is preferable that the piezoelectric multilayer film 10 is formed by adding at least one of magnesium and manganese to lead zirconate titanate, and the added amount is more than 0 and not more than 10 mol%.

Preferably, the first electrode film 2 is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium or an alloy containing the noble metal, and is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm or more and 30 nm or less.

However, when a voltage is applied between the first and second electrode films 2 and 6 through the lead wires 9a and 9b, the piezoelectric multilayer film 10 extends in the X direction in FIG. 1 . When the applied voltage is E (V), the thickness of the piezoelectric laminated film 10 is t (m), the length of the piezoelectric laminated film 10 is L (m), and the piezoelectricity of the piezoelectric laminated film 10 is When the constant is d ₃₁ (pm/V), the elongation change ΔL(m) of the piezoelectric multilayer film 10 is obtained by the following formula.

ΔL=d ₃₁ ×L×E/t

Here, the portion of the piezoelectric laminated film 10 on the side of the second electrode film 6 (in FIG. 1 , the upper portion of the piezoelectric laminated film 10 ) extends in the X direction, and the portion of the piezoelectric laminated film 10 located on the first electrode film 10 extends in the X direction. The portion on one side of the film 2 (in FIG. 1 , the lower portion of the piezoelectric multilayer film 10 ) is restrained from extending by the substrate 1 . As a result, the tip of the piezoelectric element 20 (the right end in FIG. 1 ) is displaced to the negative side in the Z direction (the lower side in FIG. 1 ). Therefore, when the application and non-application of the voltage are repeated at a constant frequency, the tip of the piezoelectric element 20 moves up and down in the Z direction by a predetermined amount of displacement. Further, the displacement characteristic of the piezoelectric body element 20 can be evaluated by examining the relationship between the applied voltage and the displacement amount of the tip of the piezoelectric body element 20 moving up and down in the Z direction.

Hereinafter, a method of manufacturing the piezoelectric element 20 will be described with reference to FIG. 2 .

FIG. 2 is a process diagram showing a method of manufacturing a piezoelectric element. First, as shown in FIG. 2(a), on a substrate 101 with a length of 20 mm, a width of 20 mm, and a thickness of 0.30 mm, a rectangular opening with a width of 5.0 mm and a length of 18.0 mm is formed with a thickness of 0.2 mm. A stainless steel mask was used to form the first electrode film 102 by the RF magnetron sputtering method described later.

Next, using a stainless steel mask with a thickness of 0.2 mm and a rectangular opening with a width of 5.0 mm and a length of 12.0 mm, a piezoelectric layer is accurately formed on the first electrode film 102 by RF magnetron sputtering. Film 110. The piezoelectric multilayer film 110 is formed by first forming the first piezoelectric thin film 104 on the first electrode film 102 by RF magnetron sputtering using a sintered target of PZT-based oxide, and then, Using the same target, the second piezoelectric thin film 105 was continuously formed on the first piezoelectric thin film 104 by the same RF magnetron sputtering method while changing only the film-forming conditions. The piezoelectric multilayer film 110 has the same structure as the schematic diagram of the film structure of the piezoelectric multilayer film 110 shown in FIG. 3 . The step of forming the piezoelectric multilayer film 110 includes a step of preferentially orienting the piezoelectric multilayer film 110 on the (111) plane.

Next, using the same stainless steel mask as above, the second electrode film 106 is precisely formed on the piezoelectric laminated film 110 by the RF sputtering method as above. In this way, as shown in FIG. 2( b ), a structure 121 having a substrate 101 and a laminate 111 can be obtained.

Next, as shown in Figure 2(c), the structure 121 is accurately cut off with a dicing saw so that it is a rectangle with a width of 3.0mm and a length of 15.0mm and one end of the first electrode film 2 (Figure 2(c) ) of the left end) exposed. As a result, a piezoelectric element structure composed of the substrate 1, the first electrode film 2, the first piezoelectric thin film 4, the second piezoelectric thin film 5, and the second electrode film 6 shown in FIG. 1 can be obtained. Part 22. Then, as shown in FIG. 2( d ), one end portion of the substrate 1 (the left end portion in FIG. 2( d )) is bonded to the stainless steel supporting substrate 7 with an epoxy-based adhesive 8 .

Next, as shown in FIG. 2( e ), the lead wire 9a is connected to one end of the first electrode film 2 with a silver paste conductive adhesive, and the lead wire 9b is connected to one end of the second electrode film 6 with a bonding wire. By this method, the piezoelectric element 20 shown in FIG. 1 can be obtained.

Hereinafter, more specific embodiments of the present invention will be described.

(first embodiment)

Silicon was used as the substrate. An iridium (Ir) thin film with a thickness of 100 nm was used as the first electrode film. The iridium thin film was prepared by heating the substrate at a temperature of 400°C in advance in a ternary RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =15:1) as The sputtering gas was formed by keeping the total gas pressure at 0.25 Pa, using a 4-inch-diameter iridium target as the first target, applying 200W of high-frequency electricity, and sputtering for 960 seconds.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is composed of a (111) preferentially oriented PZT thin film with a thickness of 50 nm, and the second piezoelectric thin film is 2. The piezoelectric thin film is composed of a (111)-oriented PZT thin film with a thickness of 3400 nm provided on the first piezoelectric thin film. In other words, the film thickness of the entire piezoelectric laminated film was 3450 nm.

The first and second piezoelectric thin films were formed using an RF magnetron sputtering device. A 6-inch-diameter sintered body target (composition molar ratio Pb:Zr:Ti=1.20:0.53:0.47) of stoichiometric structure PZT prepared by adding approximately 20 mol% of PbO in excess was used as a target. Film-forming conditions are as follows. In other words, first, in a film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film is formed on the surface is preliminarily heated and maintained at a temperature of 580°C, and a mixed gas of argon and oxygen is used as a sputtering gas. , the gas pressure is 0.2Pa, the mixing ratio is argon: oxygen=38:2, the flow rate is 40ml per minute, the plasma generation power is 3kW, and the first piezoelectric is formed in 50 seconds under these conditions. bulk film 104 . Then, the film formation was stopped, the mixing ratio of the sputtering gas was immediately changed to argon:oxygen=79:1, and other conditions were kept constant, and the second piezoelectric thin film was formed in 2900 seconds.

A platinum (Pt) thin film was used as the second electrode film. The platinum thin film was formed on the second piezoelectric thin film by RF sputtering.

In addition, in order to accurately obtain the film thickness, (111) orientation, composition, and cross-sectional structure of the first piezoelectric thin film shown in FIG. Film-forming laminated film. Regarding this sample, after observing the surface by a scanning electron microscope, analyzing by X-ray diffraction, and analyzing the composition by an X-ray microanalyzer, the sample was destroyed, and analyzed by a scanning electron microscope. The cross section was observed.

In addition, in order to accurately obtain the film thickness, (111) orientation, composition, and cross-sectional structure of the second piezoelectric thin film shown in FIG. Film-forming laminated film. Regarding this sample, as described above, observation of the surface by a scanning electron microscope, analysis by X-ray diffraction, and composition analysis by an X-ray microanalyzer were carried out. Then, this sample was broken, and the cross section was observed with a scanning electron microscope.

Then, using the structure shown in FIG. 2( b ) as a sample, the composition analysis from the surface to the depth direction of the piezoelectric multilayer film was performed by Auger spectroscopic analysis. Furthermore, the cross-section of the piezoelectric laminated film was observed with a scanning electron microscope. FIG. 4( a ) shows an enlarged electron micrograph of the cross-section of the piezoelectric laminated film, and FIG. 4( b ) shows a partially enlarged view of FIG. 4( a ).

As a result of the above analysis and the above observation, the iridium electrode is an aggregate of columnar particles with an average cross-sectional diameter of 30 nm. The first and second piezoelectric thin films exist as particle aggregates of a columnar structure in continuous contact with each other. The film thickness (length of the columnar particles) of the first piezoelectric thin film was 50 nm, and the average cross-sectional diameter of the columnar particles was 40 nm. In the second piezoelectric thin film, the film thickness (the length of the columnar particles) was 3400 nm, and the average cross-sectional diameter of the columnar particles was 100 nm. The ratio of the thickness of the piezoelectric multilayer film (the length of the columnar particles of the piezoelectric multilayer film) to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 34.5.

(Angstrom)到1.5

的X射线衍射范围中，(111)峰值强度与属于薄膜的全峰值强度的合计的百分率。也就是，结晶取向率为属于(111)的峰值强度、与锆钛酸铅镧(以下，PLZT)薄膜、PZT薄膜的X射线衍射图案的(001)、(100)、(010)、(110)、(011)、(101)、(111)等各结晶面的峰值强度的合计的比例的百分率。As a result of X-ray diffraction analysis, both the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 60%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 95%. Here, the (111) crystal orientation ratio of the PZT-based piezoelectric thin film obtained from the reflection intensity of each crystal plane of the diffraction pattern by the X-ray diffraction method is defined as the crystal lattice distance 4.2

(Angstrom) to 1.5

In the X-ray diffraction range of , the percentage of the (111) peak intensity and the total peak intensity belonging to the film. That is, the crystal orientation rate belongs to the peak intensity of (111), and (001), (100), (010), (110) of the X-ray diffraction pattern of the lead lanthanum zirconate titanate (hereinafter, PLZT) thin film and the PZT thin film. ), (011), (101), (111) and the percentage of the ratio of the total peak intensity of each crystal plane.

As a result of compositional analysis of positive ions by an X-ray microanalyzer, the compositions of the first and second piezoelectric thin films were Pb:Zr:Ti=1.15:0.53:0.47 and Pb:Zr:Ti=1.10:0.53: 0.47. That is, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and the compositions of Zr and Ti are between the first and second piezoelectric thin films. 2 Piezoelectric thin films remain unchanged, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film. In other words, the first and second piezoelectric thin films are aggregates of columnar particles whose crystal growth direction is from one side to the other side in the thickness direction of the piezoelectric multilayer film.

Then, a triangular wave voltage of 0V to -80V was applied between the first and second electrode films 2 and 6 of the piezoelectric element 20 through the lead wires 9a and 9b, and the piezoelectric body was measured using a laser Doppler vibration displacement measurement device. The displacement of the front end of the component 20 moving up and down in the Z direction. FIG. 5 is a graph showing the displacement amount of the tip of the piezoelectric body element 20 moving up and down in the Z direction when a voltage with a frequency of 2 kHz is applied. As shown in FIG. 5 , when a voltage of 0 V to −80 V was applied, the tip of the piezoelectric element 20 was displaced by a maximum of 34.0 μm. Then, the reciprocating drive by the triangular wave voltage is carried out, and after driving 100 million times (driving time 13.9 hours) and 1 billion times (driving time 138.9 hours), the driving state of the piezoelectric body element 20 is inspected, and at the same time, it is observed with an optical microscope. its appearance. The maximum displacement was also 34.0 μm after driving 1 billion times, and neither film peeling nor cracking occurred in the piezoelectric element 20 .

(second embodiment)

A heat-resistant Pyrex (registered trademark) glass was used as a substrate, and a platinum (Pt) thin film with a thickness of 150 nm was used as the first electrode film. The platinum thin film was prepared by heating the substrate at a temperature of 400°C in a 3-dimensional RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =15:1) as The sputtering gas was formed by keeping the total gas pressure at 0.25 Pa, using a platinum target as the first target, applying 200 W of high-frequency electricity, and sputtering for 1080 seconds.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is composed of a (111) preferentially oriented PZT thin film with a thickness of 100 nm, and the second piezoelectric thin film is 2 The piezoelectric thin film is composed of a (111)-oriented PZT thin film with a thickness of 4000 nm. In other words, the film thickness of the piezoelectric laminated film was set to 4100 nm.

As in the first embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering device. A 6-inch-diameter sintered body target (composition molar ratio Pb:Zr:Ti=1.10:0.50:0.50) of stoichiometric structure PZT prepared by adding approximately 10 mol% of PbO in excess was used as a target. Film-forming conditions are as follows. In other words, first, in a film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film is formed on the surface is preliminarily heated and maintained at a temperature of 550°C, and a mixed gas of argon and oxygen is used as a sputtering gas. , the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen=79:1, the flow rate is 40ml per minute, and the plasma generation power is 2kW. Under these conditions, the first piezoelectric Bulk film formation. Then, the film formation was stopped, the substrate temperature was 590° C., the plasma generation power was 3 kW, and other conditions were kept constant, and the second piezoelectric thin film was formed for 3800 seconds.

As a result of the same analyzes and observations as in the first example, the platinum electrode was an aggregate of columnar particles with an average cross-sectional diameter of 30 nm. The first and second piezoelectric thin films exist as particle aggregates of a columnar structure in continuous contact with each other. The first piezoelectric thin film has a film thickness of 100 nm, and the average cross-sectional diameter of the columnar particles is 50 nm. The second piezoelectric thin film has a film thickness of 4000 nm, and the average cross-sectional diameter of the columnar particles is 200 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 20.5.

As a result of X-ray diffraction analysis, both the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 70%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 98%.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the compositions of the first and second piezoelectric thin films were Pb:Zr:Ti=1.15:0.51:0.49 and Pb:Zr:Ti=1.00:0.51: 0.49. That is, as in the first embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the first example, a triangular wave voltage of 0 V to -80 V at a frequency of 2 kHz was applied to the piezoelectric element 20 of this example, and the displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 37.0 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

(third embodiment)

A mirror-finished heat-resistant stainless steel plate was used as the substrate, and an alloy thin film composed of iridium (Ir) containing titanium (Ti) and having a thickness of 110 nm was used as the first electrode film. The alloy thin film was prepared by heating the substrate at a temperature of 400°C in advance in a 3D RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =16:1) as For the sputtering gas, keep the total gas pressure at 0.25 Pa, use an iridium target as the first target, use a titanium target as the second target, apply 200W and 60W high-frequency electricity respectively, and sputter for 960 seconds to form. In addition, the purpose of adding titanium to iridium is to improve the adhesion with the substrate, and even if titanium is not added, the characteristics of the piezoelectric element will not be affected.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is made of (111) preferentially oriented PZT with a thickness of 10 nm and added with 10 mol % of magnesium. The second piezoelectric thin film is composed of a (111)-oriented (PZT+Mg) thin film with a thickness of 4990 nm. In other words, the film thickness of the piezoelectric laminated film was set to 5000 nm.

As in the first embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering device. A 6-inch-diameter sintered body target (composition molar ratio Pb: Zr:Ti:Mg=1.10:0.60:0.40:0.10) as a target. Film-forming conditions are as follows. In other words, first, in a film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film is formed on the surface is preliminarily heated and maintained at a temperature of 570°C, and a mixed gas of argon and oxygen is used as a sputtering gas. , the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen=38:2, the flow rate is 40ml per minute, and the plasma generation power is 3kW. Under these conditions, the first piezoelectric Bulk film formation. Then, the film formation was stopped, and the mixing ratio of the sputtering gas was immediately changed to argon:oxygen=79:1, and other conditions were kept constant, and the second piezoelectric thin film was formed in 2500 seconds.

As a result of the same analyzes and observations as in the first example, the first electrode film is composed of an iridium thin film containing 1 mol % of titanium, and is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm. The first and second piezoelectric thin films exist as particle aggregates of a columnar structure in continuous contact with each other. The first piezoelectric thin film has a film thickness of 10 nm, and the average cross-sectional diameter of the columnar particles is 40 nm. The second piezoelectric thin film has a film thickness of 4990 nm, and the average cross-sectional diameter of the columnar particles is 100 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 50.0.

As a result of X-ray diffraction analysis, both the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 50%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 95%.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the compositions of the first and second piezoelectric thin films are Pb:Zr:Ti:Mg=1.05:0.60:0.40:0.09 and Pb:Zr:Ti: Mg=1.00:0.60:0.40:0.10. That is, as in the first embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the first example, a triangular wave voltage of 0 V to -80 V at a frequency of 2 kHz was applied to the piezoelectric element 20 of this example, and the displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 36.0 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

(fourth embodiment)

A mirror-polished ceramic material (alumina) was used as the substrate, and an alloy thin film made of ruthenium (Ru) containing nickel (Ni) and having a thickness of 120 nm was used as the first electrode film. The alloy thin film was prepared by heating the substrate at a temperature of 400°C in advance in a 3D RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =16:1) as For the sputtering gas, keep the total gas pressure at 0.25 Pa, use a ruthenium target as the first target, use a nickel target as the second target, apply 200W and 60W high-frequency electricity respectively, and sputter for 960 seconds to form. In addition, the purpose of adding nickel to ruthenium is to improve the adhesion with the substrate, and even if nickel is not added, the characteristics of the piezoelectric element will not be affected.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is made of (111) preferentially oriented PZT with a thickness of 50 nm and added with 5 mol % of manganese. The second piezoelectric thin film is composed of a (111)-oriented (PZT+Mn) thin film with a thickness of 2500 nm. In other words, the film thickness of the piezoelectric laminated film was set to 2550 nm.

As in the first embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering device. A 6-inch-diameter sintered body target of PZT with a stoichiometric structure prepared by adding about 20 mol% of PbO in excess and adding 5 mol% of manganese (Mn) (composition molar ratio Pb:Zr:Ti:Mn=1.20: 0.40:0.60:0.05) as the target. Film-forming conditions are as follows. In other words, first, in a film-forming chamber equipped with the above-mentioned (PZT+Mn) target, the substrate on which the first electrode film is formed on the surface is preliminarily heated and maintained at a temperature of 550° C., using a mixed gas of argon and oxygen. As the sputtering gas, the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen=79:1, the flow rate is 40 ml per minute, and the plasma generation power is 2 kW. The first piezoelectric thin film is formed. Then, the film formation was stopped, the substrate temperature was set at 580° C., the plasma generation power was set at 3 kW, and other conditions were kept constant, and the second piezoelectric thin film was formed for 2000 seconds.

As a result of the same analyzes and observations as in the first example, the first electrode film is composed of a ruthenium thin film containing 4 mol % of nickel and is an aggregate of columnar particles with an average cross-sectional diameter of 25 nm. The first and second piezoelectric thin films exist as particle aggregates of a columnar structure in continuous contact with each other. The first piezoelectric thin film has a film thickness of 50 nm, and the average cross-sectional diameter of the columnar particles is 30 nm. The second piezoelectric thin film has a film thickness of 2500 nm, and the average cross-sectional diameter of the columnar particles is 60 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 42.5.

As a result of X-ray diffraction analysis, both the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 70%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 97%.

As a result of compositional analysis of positive ions by an X-ray microanalyzer, the compositions of the first and second piezoelectric thin films are Pb:Zr:Ti:Mn=1.10:0.40:0.60:0.05 and Pb:Zr:Ti: Mn=1.05:0.40:0.60:0.05. That is, as in the first embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the first example, a triangular wave voltage of 0 V to -80 V at a frequency of 2 kHz was applied to the piezoelectric element 20 of this example, and the displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 38.7 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

(fifth embodiment)

Silicon was used as the substrate, and a palladium (Pd) thin film with a thickness of 120 nm was used as the first electrode film. The palladium thin film was prepared by heating the substrate at a temperature of 500°C in advance in a 3-dimensional RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =16:1) as The sputtering gas was formed by keeping the total gas pressure at 0.25 Pa, using a palladium target as the first target, applying 200 W of high-frequency electricity, and sputtering for 960 seconds.

The piezoelectric laminated film 10 is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is composed of a (111) preferentially oriented PZT thin film with a thickness of 100 nm. The second piezoelectric thin film is composed of a (111)-oriented PZT thin film with a thickness of 4900 nm. In other words, the film thickness of the piezoelectric laminated film was set to 5000 nm.

As in the first embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering device. A 6-inch-diameter sintered compact target (composition molar ratio Pb:Zr:Ti=1.20:0.58:0.42) of stoichiometric structure PZT prepared by adding approximately 20 mol% of PbO in excess was used as a target. Film-forming conditions are as follows. In other words, first, in a film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film is formed on the surface is preliminarily heated and maintained at a temperature of 580°C, and a mixed gas of argon and oxygen is used as a sputtering gas. , the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen=38:2, the flow rate is 40ml per minute, and the plasma generation power is 3kW. Under these conditions, the first piezoelectric Bulk film formation. Then, the film formation was stopped, and the mixing ratio of the sputtering gas was immediately changed to argon:oxygen = 79:1, and other conditions were kept constant, and the second piezoelectric thin film was formed in 3700 seconds.

As a result of the same analyzes and observations as in the first example, the palladium electrode is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm. The first and second piezoelectric thin films exist as particle aggregates of a columnar structure in continuous contact with each other. The first piezoelectric thin film has a film thickness of 100 nm, and the average cross-sectional diameter of the columnar particles is 50 nm. The second piezoelectric thin film has a film thickness of 4900 nm, and the average cross-sectional diameter of the columnar particles is 90 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 55.5.

As a result of X-ray diffraction analysis, both the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 75%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 100%.

As a result of compositional analysis of positive ions by an X-ray microanalyzer, the compositions of the first and second piezoelectric thin films were Pb:Zr:Ti=1.10:0.58:0.42 and Pb:Zr:Ti=1.05:0.58: 0.42. That is, as in the first embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the first example, a triangular wave voltage of 0 V to -80 V at a frequency of 2 kHz was applied to the piezoelectric element 20 of this example, and the displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 41.5 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

In addition, in the first to fifth examples, three-dimensional oxides of lead (Pb), zirconium (Zr), and titanium (Ti) and oxides to which magnesium (Mg) and manganese (Mn) were added were used. PZT thin films can also use PZT films containing lanthanum (La) (that is, PLZT films) and PZT films containing ions such as niobium (Nb) and magnesium (Mg). If an oxide film with a perovskite crystal structure is used If this is the case, the same piezoelectric laminated film as in the first to fifth examples can be obtained.

(comparative example 1)

For comparison with the first to fifth examples, the following piezoelectric elements were produced.

Only the second piezoelectric thin film is formed on the first electrode film made of an iridium thin film, instead of forming a piezoelectric laminate film on the first electrode film made of an iridium thin film in the first embodiment. The embodiment is exactly the same.

Regarding the sample of this comparative example, as above, the surface was observed by a scanning electron microscope, analyzed by X-ray diffraction, and analyzed by an X-ray microanalyzer. Its cross-section was observed with an electron microscope.

As a result of the above analysis and the above observation, the piezoelectric thin film of this comparative example exists as a particle aggregate with a columnar structure. The piezoelectric thin film has a film thickness of 3500nm, and the average cross-sectional diameter of the columnar particles is 200nm. The ratio of the thickness of the piezoelectric thin film (the length of the columnar particles of the piezoelectric thin film) to the average cross-sectional diameter of the columnar particles of the piezoelectric thin film was 17.5.

As a result of X-ray diffraction analysis, the piezoelectric thin film of this comparative example has a perovskite crystal structure. The (111) crystal orientation ratio of the formation surface of the piezoelectric thin film was 55%.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the composition of the piezoelectric thin film of this comparative example was Pb:Zr:Ti=1.05:0.53:0.47.

As a result of composition analysis from the surface of the piezoelectric thin film to the depth direction by Auger spectroscopy, the composition distribution of Zr and Ti was constant from the interface with the second electrode film to the interface with the first electrode film.

That is, this comparative example is the same as the first example in that the piezoelectric thin film is a PZT film with a perovskite crystal structure grown as an aggregate of columnar particles in a direction perpendicular to the substrate surface. However, the average cross-sectional diameter of the columnar particles of the piezoelectric thin film is larger than that of the first embodiment, and the (111) crystal orientation ratio of the piezoelectric thin film is smaller than that of the first embodiment.

As in the first example, a triangular wave voltage with a frequency of 2 kHz and 0 V to -80 V was applied to the piezoelectric element of this example, and the displacement amount of the tip of the piezoelectric element moving up and down in the Z direction was measured. The tip of the piezoelectric element was displaced by a maximum of 20.0 μm, and the reciprocating drive by the triangular wave voltage was performed. After driving 100 million times, the driving condition was checked and the appearance was observed with an optical microscope. The maximum displacement The amount decreased to 3.5 μm, and partial film peeling occurred between the first electrode film and the piezoelectric thin film.

(comparative example 2)

For comparison with the first to fifth examples, the following piezoelectric elements were manufactured.

Only the second piezoelectric thin film is formed on the first electrode film composed of a palladium thin film instead of forming a piezoelectric laminate film on the first electrode film composed of a palladium thin film in the fifth embodiment. The embodiment is exactly the same.

Regarding the sample of this comparative example, as above, the surface was observed by a scanning electron microscope, analyzed by X-ray diffraction, and analyzed by an X-ray microanalyzer. Its cross-section was observed with an electron microscope.

As a result of the above analysis and the above observation, the piezoelectric thin film of this comparative example exists as a particle aggregate with a columnar structure. The piezoelectric thin film has a film thickness of 4800nm, and the average cross-sectional diameter of the columnar particles is 300nm. The ratio of the length of the columnar particles of the piezoelectric thin film to the average cross-sectional diameter of the columnar particles of the piezoelectric thin film was 16.0.

As a result of X-ray diffraction analysis, the piezoelectric thin film of this comparative example has a perovskite crystal structure. The (111) crystal orientation ratio of the piezoelectric thin film was 70%.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the composition of the piezoelectric thin film of this comparative example was Pb:Zr:Ti=1.05:0.53:0.47.

As a result of composition analysis from the surface of the piezoelectric thin film to the depth direction by Auger spectroscopy, the composition distribution of Zr and Ti was constant from the interface with the second electrode film to the interface with the first electrode film. The Pb composition is somewhat reduced (about one-twentieth of the Pb composition of the entire piezoelectric thin film) within a range of 10 nm from the interface with the first electrode film. This phenomenon cannot be observed with the precision of the Auger spectroscopic analysis, and it is considered to be caused by the diffusion of only a little Pb composition into the first electrode film.

That is, this comparative example is the same as the fifth example in that the piezoelectric thin film is a PZT film with a perovskite crystal structure grown as an aggregate of columnar particles in a direction perpendicular to the substrate surface. However, the difference from the fifth embodiment lies in that the average cross-sectional diameter of the columnar particles of the piezoelectric thin film is larger than that of the fifth embodiment, the (111) crystal orientation ratio of the piezoelectric thin film is smaller than that of the fifth embodiment, and the piezoelectric thin film is smaller than that of the first embodiment. The Pb composition near the interface of the electrode film is the same as the Pb composition of the entire piezoelectric thin film, and the Pb composition at the interface with the first electrode film is somewhat reduced.

As in the fifth example, a triangular wave voltage with a frequency of 2 kHz and 0 V to -80 V was applied to the piezoelectric element of this comparative example, and the displacement amount of the tip of the piezoelectric element moving up and down in the Z direction was measured. The tip of the piezoelectric element was displaced by a maximum of 22.0 μm. Then, the reciprocating drive by the triangular wave voltage was carried out, and after driving 1 billion times, the result of inspection of the driving state and observation of the appearance with an optical microscope was carried out, and the driving was stopped. Membrane peeling occurred.

(Embodiment 2)

This embodiment is an inkjet head including the piezoelectric element according to Embodiment 1 of the present invention. Hereinafter, this inkjet head will be described.

FIG. 6 is a schematic configuration diagram showing an inkjet head 201 according to Embodiment 2 of the present invention. As shown in Figure 6, the inkjet head 201 consists of 10 ink ejection elements 202 arranged in a row and having the same shape, and an individual electrode 33 connected to each ink ejection element 202 to drive each ink ejection element 202. The driving power supply element 203 constitutes. The drive power supply element 203 supplies a voltage to the individual electrodes 33 of the respective ink discharge elements 202 through bonding wires.

FIG. 7 is an exploded perspective view in which a part of the ink discharge element 202 is cut away. As shown in FIG. 7 , A is a pressure chamber component (pressure chamber component), and the pressure chamber component A has an elliptical pressure chamber opening 31 with a minor axis of 200 μm and a major axis of 400 μm. B is an actuator part provided so as to cover the upper end opening surface of the pressure chamber opening part 31 . C is an ink flow path component arranged to cover the lower end opening surface of the pressure chamber opening 31 . In other words, the pressure chamber opening 31 of the pressure chamber part A is partitioned by the actuator part B and the ink flow path part C positioned above and below, thereby forming a pressure chamber 32 with a thickness of 0.2 mm. The actuator part B comprises individual electrodes 33 located above the pressure chamber 32 . A common liquid chamber 35 shared between the pressure chambers 32 of the respective ink discharge elements 202, a supply port 36 communicating the common liquid chamber 35 and the pressure chamber 32, and a port communicating with the pressure chamber 32 are formed in the ink liquid flow path component C. The ink flow path 37 for flowing out the ink in the pressure chamber 32 . D is a nozzle plate, and the nozzle hole 38 having a diameter of 30 μm communicating with the ink flow path 37 is perforated in the nozzle plate D. As shown in FIG. The parts A to D are bonded together with an adhesive, whereby the ink discharge element 202 can be obtained.

A more specific embodiment of the actuator unit B will be described below.

(sixth embodiment)

The actuator unit B will be described with reference to FIG. 8 . FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7 . _As shown in FIG. 8, the actuator part B has: an individual electrode (first electrode film) 33 made of an iridium (Ir) thin film with a thickness of 100 nm; _0.53 Ti _0.48 O ₃ is a first piezoelectric thin film 42 composed of a PZT thin film with a thickness of 50 nm; the thickness immediately below the first piezoelectric thin film 42 and represented by Pb _1.10 Zr _0.53 Ti _0.47 O ₃ is A second piezoelectric thin film 43 made of a 3500nm PZT thin film; a second electrode film 44 made of a platinum thin film with a thickness of 100nm directly below the second piezoelectric thin film 43; The vibrating body layer (vibrating plate) 45 is composed of a chromium (Cr) thin film with a thickness of 3500 nm directly below. The vibrator layer 45 is displaced and vibrated by the piezoelectric effect of the first and second piezoelectric thin films 42 and 43 . The second electrode film 44 and the vibrator layer 45 are shared between the pressure chambers 32 of the respective ink discharge elements 202 . The first and second piezoelectric thin films 42 and 43 are processed to have the same shape as the individual electrodes 33 . On the second electrode film 44, around the lamination film composed of the individual electrode 33, the first piezoelectric thin film 42, and the second piezoelectric thin film 43, a poly(acyl)substrate film having the same thickness as the above lamination film is provided. An electrically insulating organic film 46 made of amine resin. On the electrically insulating organic film 46, a lead-out electrode film 47 connected to the individual electrode 33 and composed of a lead-shaped metal thin film with a thickness of 100 nm is provided. The individual electrode 33 , the piezoelectric multilayer film composed of the first and second piezoelectric thin films 42 and 43 , and the second electrode film 44 constitute a piezoelectric element. This piezoelectric body element is the same as the piezoelectric body element 20 of Embodiment 1, and therefore, it is possible to obtain the actuator unit B with high characteristics.

Hereinafter, a method of manufacturing the actuator unit B will be described.

9 and 10 are process diagrams showing a method of manufacturing the actuator unit B. As shown in FIG. First, on a silicon substrate 51 having a length of 20 mm, a width of 20 mm, and a thickness of 0.3 mm, the first electrode film 52, the first piezoelectric thin film 54, and the first 2. Piezoelectric thin film 55 and second electrode film 44. Accordingly, the structure 56 shown in FIG. 9( a ) can be obtained.

Next, as shown in FIG. 9(b), at room temperature, a vibrator layer 45 made of a chromium (Cr) thin film was formed on the structure 56 with a thickness of 3500 nm by RF sputtering.

Next, as shown in FIG. 9(c), the vibrator layer 45 is attached to the glass pressure chamber member 58 with an acrylic resin adhesive 57. As shown in FIG. The pressure chamber member 58 is provided so as to face the vibrating body layer 45 , and the adhesive 57 is interposed between the pressure chamber member 58 and the vibrating body layer 45 .

Next, as shown in FIG. 9( d ), the silicon substrate 51 is removed by dry etching with SF ₆ gas using a plasma reactive etching device.

Next, as shown in FIG. 9( e), the non-etched portion of the laminated film composed of the first electrode film 52, the first piezoelectric thin film 54, and the second piezoelectric thin film 55 is correctly etched using a photoresist resin film 59. The ground pattern was an elliptical pattern with a minor axis of 180 μm and a major axis of 380 μm. Then, etching was performed using dry etching using argon (Ar) gas and wet etching using weak hydrofluoric acid. In this way, as shown in FIG. 10( a ), a photoresist pattern processed into a photoresist pattern and composed of individualized individual electrodes 33 , first piezoelectric thin films 42 and second piezoelectric thin films 43 can be obtained. The actuator structure of the laminated film. Then, as shown in FIG. 10(b), the photoresist resin film 59 is treated with a resist stripper to remove it.

Next, as shown in FIG. 10(c), an electrically insulating organic film 46 is formed on the second electrode film 44 by printing. Then, as shown in FIG. 10(d), a lead electrode film 47 is formed on the electrically insulating organic film 46 by the DC sputtering method. In this way, the actuator unit B shown in FIG. 8 can be obtained.

Thirty ink discharge elements 202 were manufactured by the manufacturing method shown in this example. A sinusoidal waveform voltage of 0 V to -60 V at a frequency of 200 Hz was applied between the two electrode films 33 and 44 of these ink ejection elements 202, and the above-mentioned driving conditions were checked. Even after driving 1 billion times, all the ink discharge elements 202 did not fail.

Using ten of these ink discharge elements 202, the inkjet head 201 shown in FIG. 6 was produced. In this inkjet head 201, a voltage is supplied from the drive power supply element 203 to the individual electrodes 33 of each ink ejection element 202 through bonding wires, and the vibration layer is vibrated by the piezoelectric effect of the first and second piezoelectric thin films 42 and 43. 45 is displaced and vibrated in the layer thickness direction, and the ink liquid in the common liquid chamber 35 is discharged from the nozzle hole 38 through the supply port 36 , the pressure chamber 32 and the ink flow path 37 .

Here, in this inkjet head 201, since the first and second piezoelectric thin films 42, 43 constituting the actuator portion B of the ink discharge element 202, the crystal orientations of the film surfaces are all (111) planes, and the piezoelectric thin films All of the electric displacement characteristics have large values, so a large piezoelectric displacement can be obtained. In addition, since the individual electrodes 33 and the first piezoelectric thin film 54 have high adhesiveness, even if a high voltage is applied to drive with a large displacement, failure due to film peeling is unlikely to occur, and a stable and stable electrode with high reliability can be realized. drive. In addition, since the piezoelectric displacement is large, the discharge capability of the ink liquid is high, and the limit of the adjustment width of the power supply voltage can be increased. Therefore, it is possible to easily perform control to reduce the difference in discharge of the ink liquid between the respective ink discharge elements 202 .

(the seventh embodiment)

Referring to FIG. 11, an actuator unit B having a structure different from that of the sixth embodiment will be described. 11 is a view corresponding to the sectional view taken along line VIII-VIII in FIG. 7 of an actuator unit B according to a seventh example of the second embodiment. _As shown in FIG. 11, the actuator part B has: an individual electrode (second electrode film) 33 made of a platinum (Pt) thin film with a thickness of 100 nm; _0.58 Ti _0.42 O ₃ is a second piezoelectric thin film 43 composed of a PZT thin film with a thickness of 4500 nm; the thickness immediately below the second piezoelectric thin film 43 and represented by Pb _1.10 Zr _0.58 Ti _0.42 O ₃ is A first piezoelectric thin film 42 made of a PZT thin film of 80 nm; a first electrode film 52 located directly below the first piezoelectric thin film 42 and made of palladium with a thickness of 200 nm; Immediately below, is the vibrator layer 45 made of a silicon oxide (SiO ₂ ) thin film with a thickness of 5000 nm. The vibrator layer 45 is displaced and vibrated by the piezoelectric effect of the first and second piezoelectric thin films 42 and 43 . The first electrode film 52 and the vibrator layer 45 are shared between the pressure chambers 32 of the respective ink discharge elements 202 . The first and second piezoelectric thin films 42 and 43 are processed to have the same shape as the individual electrodes 33 . On the first electrode film 52, around the laminated film composed of the individual electrodes 33, the first piezoelectric thin film 54, and the second piezoelectric thin film 55, a poly(acyl)substrate film having the same thickness as the above-mentioned laminated film is provided. An electrically insulating organic film 46 made of amine resin. On the electrically insulating organic film 46, a lead-out electrode film 47 connected to the individual electrode 33 and composed of a lead-shaped metal thin film with a thickness of 100 nm is provided. The individual electrodes 33 , the piezoelectric multilayer film composed of the first and second piezoelectric thin films 54 and 55 , and the first electrode film 52 constitute a piezoelectric element. This piezoelectric body element is the same as the piezoelectric body element 20 of Embodiment 1, and therefore, it is possible to obtain the actuator unit B with high characteristics.

Hereinafter, a method of manufacturing the actuator unit B will be described.

12 and 13 are process diagrams showing a method of manufacturing the actuator unit B. As shown in FIG. First, the vibrating body layer 45 is formed on a silicon substrate 51 (pressure chamber substrate) having a length of 20 mm, a width of 20 mm, and a thickness of 0.3 mm. Then, on the vibrating body layer 45, the same method as in the fifth embodiment of the first embodiment is formed. As in the example, the first electrode film 52 , the first piezoelectric thin film 54 , the second piezoelectric thin film 55 , and the second electrode film 44 are laminated in this order. Accordingly, the structure 56 shown in FIG. 12( a ) can be obtained.

Next, as shown in FIG. 12(b), using a photoresist resin film 59, the non-etched portion of the laminated film composed of the second electrode film 44, the first piezoelectric thin film 54, and the second piezoelectric thin film 55 is correctly etched. The ground pattern was an elliptical pattern with a minor axis of 180 μm and a major axis of 380 μm.

Then, etching was performed using dry etching using argon (Ar) gas and wet etching using weak hydrofluoric acid. In this way, as shown in FIG. 12(c), a photoresist pattern processed into a photoresist pattern and composed of individualized individual electrodes 33, second piezoelectric thin films 43, and first piezoelectric thin films 42 can be obtained. The actuator structure of the laminated film. Thereafter, as shown in FIG. 12(d), the photoresist resin film 59 is treated with a resist stripper to remove it. Then, as shown in FIG. 13(a), an electrically insulating organic film 46 is formed on the first electrode film 52 by a printing method.

Next, as shown in FIG. 13( b ), a part of the silicon substrate 51 was removed by dry etching with SF ₆ gas using a plasma reactive etching device to form a pressure chamber 32 .

Next, as shown in FIG. 13(c), a lead-out electrode film 47 is formed on the electrically insulating organic film 46 by DC sputtering. Accordingly, the actuator portion B shown in FIG. 11 can be obtained.

Thirty ink discharge elements 202 were manufactured by the manufacturing method shown in this example. A sinusoidal waveform voltage of 0 V to -60 V at a frequency of 200 Hz was applied between the two electrode films 33 and 52 of these ink ejection elements 202, and the above-mentioned driving conditions were checked. Even after driving 1 billion times, all the ink discharge elements 202 did not fail.

Using ten of these ink discharge elements 202, the inkjet head 201 shown in FIG. 6 was produced. Using this inkjet head 201, the same effect as that of the sixth embodiment can be obtained.

(Embodiment 3)

This embodiment is an inkjet recording device including the inkjet head according to Embodiment 2 of the present invention. Hereinafter, this ink jet recording device will be described.

14 is a schematic perspective view of an ink jet recording device according to Embodiment 3 of the present invention. As shown in FIG. 14 , an inkjet recording device 81 includes an inkjet head 201 according to Embodiment 2 for performing recording using the piezoelectric effect of the first and second piezoelectric thin films 42 and 43 . The ejected ink drops onto a recording medium 82 such as paper to perform recording on the recording medium 82 . The inkjet head 201 is mounted on a conveyance part 84 (relative movement mechanism) which is slidably mounted on a conveyance shaft 83 (relative movement mechanism) provided along the main scanning direction (X direction in FIG. 14 ). . Then, the conveyance unit 84 moves back and forth along the conveyance shaft 83 to move the inkjet head 201 back and forth in the main scanning direction X. The inkjet recording device 81 includes a plurality of rollers 85 (relative movement mechanism) for moving the recording medium 82 in the sub-scanning direction Y substantially perpendicular to the main scanning direction X. And, in the inkjet type recording device 81, when the inkjet head 201 is moved back and forth in the main scanning direction X by the transport shaft 83, etc., the ink in the pressure chamber 32 is ejected from the nozzle hole 38 to the recording medium 82, and recording is performed. .

As described above, according to this embodiment, since the inkjet recording device 81 is produced using the inkjet head 201 of Embodiment 2 which can easily control the ink discharge difference between the ink discharge elements 202, it is possible to Variations in recording on the recording medium 82 are reduced, and thus a highly reliable inkjet recording device 81 can be realized.

(Embodiment 4)

This embodiment is an angular velocity sensor including the piezoelectric element according to Embodiment 1 of the present invention. Hereinafter, this angular velocity sensor will be described.

15 and 16 are schematic diagrams and cross-sectional views of an angular velocity sensor 400 according to Embodiment 4 of the present invention. This angular velocity sensor 400 is a tuning fork type, and is widely used in navigation devices and the like mounted in vehicles.

The angular velocity sensor 400 includes a substrate 500 made of a silicon wafer with a thickness of 0.3 mm. This substrate 500 has a fixed portion 500a and a pair of vibrating portions 500b extending from the fixed portion 500a in a predetermined direction (the direction in which the center axis of rotation of the detected angular velocity extends. In this embodiment, the Y direction in FIG. 15 ). , 500b. These fixed part 500a and a pair of vibrating parts 500b, 500b are in the shape of a tuning fork when viewed from the thickness direction of the substrate 500 (Z direction in FIG. 500b extend parallel to each other in a state of being aligned in the width direction. In addition, the substrate 500 may be a glass substrate, a metal substrate, a ceramic substrate, or the like.

A first electrode film 502, a first piezoelectric thin film 504, a second piezoelectric thin film 505, and a second piezoelectric thin film 504 are sequentially stacked on the vibrating portion 500b side of each vibrating portion 500b of the substrate 500 and the fixed portion 500a. Electrode film 506 . The first electrode film 502 , the piezoelectric multilayer film composed of the first and second piezoelectric thin films 504 and 505 , and the second electrode film 506 constitute a piezoelectric element. This piezoelectric element is the same as the piezoelectric element 20 in the first embodiment. In other words, the first electrode film 502, the first piezoelectric thin film 504, the second piezoelectric thin film 505, and the second electrode film 506 are the same as the first electrode film 2 and the first piezoelectric thin film of Embodiment 1, respectively. 4. The second piezoelectric thin film 5 and the second electrode film 6 are the same.

The second electrode film 506 is patterned into two driving electrodes 507, 507 for vibrating the vibrating portion 500b in its width direction (X direction in FIG. One detection electrode 508 for deformation (deflection) in the thickness direction (Z direction in FIG. 15 ).

The two drive electrodes 507, 507 are provided at both ends of the vibrator 500b in the width direction (X direction) and across the entire length direction of the vibrator 500b (Y direction in FIG. 15). An end portion of each driving electrode 507 on the fixed portion 500a side is located on the fixed portion 500a to form a connection terminal 507a. In addition, only one driving electrode 507 may be provided on one end portion in the width direction of each vibrating portion 500b.

On the other hand, the detection electrode 508 is provided at the central portion in the width direction of the vibrating portion 500b and across the entire longitudinal direction of the vibrating portion 500b. The end portion of the detection electrode 508 on the side of the fixed portion 500a is located on the fixed portion 500a to form a connection terminal 508a similarly to the drive electrode 507 . In addition, a plurality of detection electrodes 508 may be provided on each vibrating portion 500b.

The first electrode film 502 has a connection terminal 502a protruding toward the side opposite to the vibrating part 500b at the center position between the pair of vibrating parts 500b, 500b on the fixed part 500a.

However, a frequency voltage resonant with the natural vibration of the vibrating part 500b is applied between the first electrode film 502 on each vibrating part 500b and the two drive electrodes 507, 507, so that the vibrating part 500b vibrates in its width direction. That is to say, a ground voltage is applied to the first electrode film 502, and a voltage opposite to each other is applied to the two drive electrodes 507, 507. In this way, when one end side of each vibrating portion 500b in the width direction is extended, The other end side of the vibrating portion 500b shrinks, and the vibrating portion 500b deforms at its other end side, and when one end side in the width direction of each vibrating portion 500b contracts, the other end side of the vibrating portion 500b elongates, and the vibrating portion 500b deforms at its one end side. By alternately repeating this action, the vibrating portion 500b vibrates in its width direction. In addition, even if a voltage is applied to only one of the two driving electrodes 507, 507 on each vibrating portion 500b, it is possible to vibrate the vibrating portion 500b in the width direction thereof. In addition, the pair of vibrating parts 500b, 500b are deformed toward opposite directions in the width direction of each vibrating part 500b, and are positioned at the center between the pair of vibrating parts 500b, 500b. The central line L vibrates symmetrically.

In the angular velocity sensor 400, when the pair of vibrating parts 500b, 500b vibrate symmetrically with respect to the central line L in the width direction (X direction), if an angular velocity ω is applied around the central line L, the two vibrating parts 500b, 500b, 500b is bent and deformed in its thickness direction (Z direction) due to Coriolis force (a pair of vibrating parts 500b, 500b are bent by the same amount in opposite directions). In this way, the piezoelectric multilayer film is also bent, and a voltage corresponding to the magnitude of the Coriolis force is generated between the first electrode film 502 and the detection electrode 508 . The angular velocity ω can be detected from the magnitude of this voltage (Coriolis force). That is, if the velocity in the width direction of each vibrating portion 500b is v and the mass of each vibrating portion 500b is m, the Coriolis force Fc=2mvω, so it can be known from the Coriolis force Fc Angular velocity ω.

Hereinafter, a method of manufacturing angular velocity sensor 400 will be described with reference to FIGS. 17 and 18 . First, as shown in Figure 17(a), prepare a substrate 500 made of a silicon wafer (also refer to Figure 18) with a thickness of 0.3 mm and a diameter of 4 inches, and as shown in Figure 17(b), sputtering A first electrode film 502 made of an iridium (Ir) thin film with a thickness of 100 nm was formed on a substrate 500 by using the method. The first electrode film 502 was obtained by heating the substrate 500 to 400° C. using a sputtering apparatus, and forming a film using an iridium (Ir) target in an argon gas of 1 Pa with 200 W high-frequency power for 10 minutes.

Next, as shown in FIG. 17(c), a first piezoelectric thin film 504 is formed on the first electrode film 502 by sputtering, and then, as shown in FIG. The second piezoelectric thin film 505 is continuously formed on the electric thin film 504 to form a piezoelectric multilayer film. The first piezoelectric thin film 504 is made of a (111) preferentially oriented PZT film with a thickness of 100 nm, and the second piezoelectric thin film 505 is made of a (111) oriented PZT thin film with a thickness of 2900 nm. The piezoelectric laminated film is formed as follows: First, a 6-inch-diameter sintered body target (composition molar ratio Pb:Zr: Ti=1.20:0.53:0.47) was used as a target, the silicon substrate 500 on which the first electrode film 502 was formed on the surface was heated and kept at a temperature of 580° C., and a mixed gas of argon and oxygen was used as a sputtering gas, so that The gas pressure is 0.2Pa, the mixing ratio is argon:oxygen=38:2, the flow rate is 40ml per minute, and the plasma generation power is 3kW. Under these conditions, the first piezoelectric body is heated for 50 seconds. The thin film 504 was formed, and then the film formation was stopped. Immediately, the mixing ratio of the sputtering gas was changed to argon:oxygen=79:1, and other conditions remained unchanged, and the second piezoelectric thin film 505 was formed in 2500 seconds. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on the (111) plane.

Next, as shown in FIG. 17(e), a second electrode film 506 having a thickness of 100 nm was formed on the second piezoelectric thin film 505 by sputtering. The second electrode film 506 was formed by using a platinum (Pt) target in an argon gas of 1 Pa at room temperature with a high-frequency electric current of 200 W for 10 minutes.

Next, as shown in FIG. 17( f ) and FIG. 18 , the second electrode film 506 is patterned to form drive electrodes 507 , 507 and detection electrodes 508 . That is, a photosensitive resin is coated on the second electrode film 506, and the pattern of the driving electrodes 507, 507 and the detection electrodes 508 is exposed to the photosensitive resin, and then, the photosensitive resin of the unexposed part is removed, and the removal is performed by etching. The portion of the second electrode film 506 covered with the photosensitive resin is removed, and then the photosensitive resin on the drive electrodes 507, 507 and the detection electrode 508 is removed.

Next, the second piezoelectric thin film 505, the first piezoelectric thin film 504, and the first electrode film 502 are patterned, and at the same time, the substrate 500 is patterned to form the fixed portion 500a and the vibrating portions 500b, 500b. Then, the substrate 500 is processed into a tuning fork shape as shown in FIG. 15 . In this way, the angular velocity sensor 400 can be obtained.

Hereinafter, for comparison with the angular velocity sensor 400 of this embodiment, a conventional angular velocity sensor 401 will be described with reference to FIG. 19 .

The conventional angular velocity sensor 401 includes a piezoelectric body 600 made of a crystal having a thickness of 0.3 mm. The piezoelectric body 600 has a fixed portion 600 a and a fixed portion from the fixed portion 600 similarly to the substrate 500 of the angular velocity sensor 400 of this embodiment. 600a is a pair of vibrating parts 600b and 600b extending parallel to each other in a predetermined direction (Y direction in FIG. 19 ). In addition, one driving electrode 603 for vibrating the vibrating portion 600b in its width direction (X direction in FIG. 19 ) is provided on both sides of each vibrating portion 600b in the thickness direction (Z direction in FIG. 19 ). One detection electrode 607 for detecting deformation in the thickness direction of the vibrating portion 600b is provided on each of the two side surfaces.

In the conventional angular velocity sensor 401, a frequency voltage that resonates with the natural vibration of the vibrating portion 600b is applied between the two drive electrodes 603, 603 of each vibrating portion 600b. Like the angular velocity sensor 400 of this embodiment, a pair of The vibrating parts 600b, 600b vibrate symmetrically with respect to the central line L located at the center between the pair of vibrating parts 600b, 600b in the width direction (X direction). At this time, when an angular velocity ω is applied around the central line L, the pair of vibrating parts 600b and 600b are bent and deformed in the thickness direction (Z direction) due to Coriolis force, and two of the vibrating parts 600b detect A voltage corresponding to the magnitude of the Coriolis force is generated between the electrodes 607, 607, and the angular velocity ω can be detected from the magnitude of the voltage (Coriolis force).

In the conventional angular velocity sensor 401, there is such a problem that since the piezoelectric body 600 made of crystal is used, its piezoelectric constant is -3pC/N, which is quite low, and since the fixed part 600a and vibration 600b, 600b, so it is difficult to miniaturize, and the dimensional accuracy is low.

On the other hand, in the angular velocity sensor 400 of this embodiment, since the part (vibration part 500b) that detects the angular velocity is composed of the same piezoelectric body element as the piezoelectric body element 20 of the first embodiment, the piezoelectric constant can be increased to It is about 40 times that of the conventional angular velocity sensor 401 and can be extremely miniaturized. In addition, microfabrication can be performed using thin film formation technology, and dimensional accuracy can be significantly improved. Furthermore, even if mass-produced industrially, angular velocity sensor 400 with good characteristics, little variation, withstand voltage, and reliability can be obtained.

In addition, in this embodiment, only one pair of vibrating portions 500b, 500b is provided on the substrate 500, but multiple pairs of vibrating portions 500b, 500b may be provided in order to detect rotations of multiple axes extending in various directions. the angular velocity.

In addition, in this embodiment, the first electrode film 502, the first piezoelectric thin film 504, and the second electrode film 502 are stacked in this order on each vibrating portion 500b of the substrate 500 and the part of the fixed portion 500a on the vibrating portion 500b side. The piezoelectric thin film 505 and the second electrode film 506 may be laminated only on each vibrating portion 500b.

(Embodiment 5)

FIG. 20 is a perspective view of a piezoelectric element 20 according to Embodiment 5 of the present invention. As shown in FIG. 20 , the piezoelectric element 20 includes a rectangular plate-shaped substrate 1 having a length of 15.0 mm, a thickness of 0.40 mm, and a width of 3.0 mm, and a laminate 11 disposed on the substrate 1 . The substrate 1 functions as a vibrating plate that prevents expansion and contraction due to the piezoelectric effect of the laminated body 11 . The piezoelectric body element 20 has a width of 3.0 mm. Piezoelectric element 20, one end (left end in FIG. 20 ) with a width of 3.0 mm and a length of 3.0 mm is fixed to a stainless steel support substrate 7 (width 3.0 mm) with a thickness of 1.0 mm by an epoxy-based adhesive 8 . , the depth is 10.0 mm), therefore, the piezoelectric body element 20 constitutes a beam with a single side.

A first electrode film 2 is provided on a substrate 1 . On the remaining part (that is, the first electrode film 2 has a width of 3.0 mm and a length of 12.0 mm) other than one end portion (the left end portion in FIG. 20 ) of the first electrode film 2 is provided with the first electrode film 2 with the priority of (111). The orientation control film 3 is composed of a lead lanthanum zirconate titanate (hereinafter, PLZT)-based oxide thin film having a perovskite crystal structure with crystal orientation. On the orientation control film 3 is provided a piezoelectric multilayer film 10 having the same size as the orientation control film 3 and composed of a PZT-based oxide thin film having a perovskite crystal structure with a (111) preferential crystal orientation. The piezoelectric laminated film 10 is composed of a first piezoelectric thin film 4 and a second piezoelectric thin film 5 provided on the first piezoelectric thin film 4 . In the piezoelectric multilayer film 10 , crystal orientation is controlled by the orientation control film 3 . The second electrode film 6 having a thickness of 250 nm is provided on the piezoelectric multilayer film 10 . Metal lead wires 9a, 9b having a thickness of 0.1 mm are connected to the first and second electrode films 2, 6, respectively. In addition, as shown in FIG. 20 , the laminated body 11 is composed of the first electrode film 2 , the orientation control film 3 , the piezoelectric laminated film 10 , and the second electrode film 6 .

Hereinafter, the characteristics of this embodiment will be described.

The orientation control film 3 is made of a perovskite-type oxide that is preferentially oriented on the (111) plane of the cubic or tetragonal system. The piezoelectric multilayer film 10 is composed of a perovskite-type oxide preferentially oriented on the (111) plane of the rhombohedral system or the tetragonal system. The first and second piezoelectric thin films 4 and 5 are aggregates of columnar particles that are in continuous contact with each other (see FIG. 22 ). The average cross-sectional diameter of the columnar particles of the second piezoelectric thin film 5 is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film 4 . The ratio of the thickness of the piezoelectric laminated film 10 to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film 5 is 20 or more and 60 or less.

Preferably, the columnar particles of the first piezoelectric thin film 4 have an average cross-sectional diameter of not less than 40 nm and not more than 70 nm, and a length of not less than 5 nm and not more than 100 nm. Preferably, the columnar particles of the second piezoelectric thin film 5 have an average cross-sectional diameter of not less than 60 nm and not more than 200 nm, and a length of not less than 2500 nm and not more than 5000 nm.

Preferably, the first and second piezoelectric thin films 4 and 5 are composed of oxides mainly composed of perovskite-type lead zirconate titanate, and the (111) crystal orientation ratio of the first piezoelectric thin film 4 is equal to or greater than 50. % is less than or equal to 80%, and the (111) crystal orientation ratio of the second piezoelectric thin film 5 is greater than or equal to 95% and less than or equal to 100%.

The chemical composition ratio of the piezoelectric laminated film 10 is represented by Pb:Zr:Ti=(1+a):b:(1-b), and the b value of the first and second piezoelectric thin films 4 and 5 is preferably The same value of 0.40 or less and 0.60 or more, the Pb content of the first piezoelectric thin film 4 is greater than the Pb content of the second piezoelectric thin film 5, and the a value of the first piezoelectric thin film 4 is greater than or equal to 0.05 and less than or equal to 0.15, and the a value of the second piezoelectric thin film 5 is greater than or equal to 0 and less than or equal to 0.10. Alternatively, it is preferable that the piezoelectric multilayer film 10 is formed by adding at least one of magnesium and manganese to lead zirconate titanate, and the added amount is more than 0 and not more than 10 mol%.

Preferably, the orientation control film 3 is composed of perovskite-type lead lanthanum zirconate titanate oxide as a main component, and the orientation control film has a (111) crystal orientation ratio of 50% or more.

The chemical composition ratio of the orientation control film 3 is represented by Pb:La:Zr:Ti=x×(1-z):z:y:(1-y), preferably the value of x is greater than or equal to 1.0 and less than or equal to 1.20, The y value is greater than or equal to 0 and less than or equal to 0.20, and the z value is more than 0 and less than or equal to 0.30. Alternatively, it is preferable that the orientation control film 3 is formed by adding at least one of magnesium and manganese to lead lanthanum zirconate titanate, and the added amount exceeds 0 and is equal to or less than 10 mol%.

Preferably, the first electrode film is composed of a noble metal formed of platinum (Pt), iridium (Ir), palladium (Pd), or ruthenium (Ru), or an alloy containing the noble metal, and is columnar particles with an average cross-sectional diameter of 20 nm or more and 30 nm or less. aggregates.

However, when a voltage is applied between the first and second electrode films 2, 6 through the lead wires 9a, 9b, the piezoelectric laminated film 10 extends in the X direction in FIG. The front end of 20 (the right end in FIG. 20 ) is displaced to the negative side in the Z direction (the lower side in FIG. 20 ).

Hereinafter, a method of manufacturing the piezoelectric element 20 will be described with reference to FIG. 21 .

FIG. 21 is a process diagram showing a method of manufacturing the piezoelectric element 20 . First, as shown in FIG. 21( a ), on a substrate 101 with a length of 20 mm, a width of 20 mm, and a thickness of 0.3 mm, a substrate 101 with a width of 5.0 mm and a length of 18.0 mm is used to form a rectangular opening with a thickness of 0.2 mm. Using a stainless steel mask, the first electrode film 102 was formed by RF magnetron sputtering.

Next, an orientation control film was accurately formed on the first electrode film 102 by RF magnetron sputtering using a stainless steel mask with a thickness of 0.2 mm and a rectangular opening with a width of 5.0 mm and a length of 12.0 mm. 103. The step of forming the orientation control film 103 includes a step of preferentially orienting the orientation control film 103 on the (111) plane.

Next, using a stainless steel mask with a thickness of 0.2 mm and a rectangular opening with a width of 5.0 mm and a length of 12.0 mm, a piezoelectric layer was accurately formed on the orientation control film 103 by RF magnetron sputtering. Film 110. The piezoelectric laminated film 110 is formed by using a sintered target of PZT-based oxide, first forming the first piezoelectric thin film 104 on the orientation control film 103 by RF magnetron sputtering, and then using The second piezoelectric thin film 105 was continuously formed on the first piezoelectric thin film 104 by the same RF magnetron sputtering method using the same target and only changing the film forming conditions. The piezoelectric multilayer film 110 has the same structure as the schematic diagram of the film structure of the piezoelectric multilayer film shown in FIG. 22 . The step of forming the piezoelectric multilayer film 110 includes a step of preferentially orienting the piezoelectric multilayer film 110 on the (111) plane through the orientation control film 103 .

Next, using the same stainless steel mask as above, the second electrode film 106 was precisely formed on the piezoelectric multilayer film 110 by the RF magnetron sputtering method as above. Therefore, as shown in FIG. 21( b ), a structure 121 including the substrate 101 and the laminate 111 can be obtained.

Next, as shown in Figure 21 (c), cut off the structure 121 accurately with a dicing saw, so that it is a rectangle with a width of 3.0 mm and a length of 15.0 mm and one end of the first electrode film (Figure 21 (c) left end) exposed. In this way, the substrate 1, the first electrode film 2, the orientation control film 3, the first piezoelectric thin film 4, the second piezoelectric thin film 5, and the second electrode film 6 shown in FIG. 20 can be obtained. Piezoelectric element structure part 22 . Then, as shown in FIG. 21( d ), one end portion of the substrate 1 (the left end portion in FIG. 21( d )) is bonded to the stainless steel support substrate 7 with an epoxy-based adhesive 8 .

Next, as shown in Figure 21 (e), the lead wire 9a is connected to one end (the left end of Figure 21 (e)) of the first electrode film 2 with a silver paste conductive adhesive, and the lead wire 9b is connected with a welding wire. At one end of the second electrode film 6 (the left end in FIG. 21( e )). By this method, the piezoelectric body element 20 shown in FIG. 20 can be obtained.

Hereinafter, more specific embodiments of the present invention will be described.

(eighth embodiment)

Silicon is used as a substrate. An iridium (Ir) thin film with a thickness of 100 nm was used as the first electrode film. The iridium thin film was formed by heating the substrate at a temperature of 400° C. in advance in a 3-dimensional RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =15 : 1) As the sputtering gas, the total gas pressure was kept at 0.25 Pa, a 4-inch-diameter iridium target was used as the first target, 200 W of high-frequency power was applied, and sputtering was performed for 960 seconds.

A (111) preferentially oriented lanthanum lead titanate (hereinafter, referred to as PLT) thin film with a thickness of 40 nm was used as the orientation control film. The PLT thin film is formed by preheating the substrate on which the first electrode film is formed on the surface at a temperature of 550°C in the same 3-dimensional RF magnetron sputtering device, using a mixture of argon and oxygen. Gas (gas volume ratio Ar:O ₂ =25:1) was used as the sputtering gas, and the total gas pressure was maintained at 0.5 Pa, and the 4-inch PLT of the stoichiometric structure prepared by adding about 20 mol% of PbO in excess A diameter sintered body target (composition molar ratio Pb:La:Ti=1.10:0.10:1.0) was used as the second target, and 250W of high-frequency power was applied, and sputtering was performed for 3000 seconds.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film. The first piezoelectric thin film is made of a (111) preferentially oriented PZT thin film with a thickness of 50 nm, and the second piezoelectric thin film is made of a (111) oriented PZT thin film with a thickness of 3500 nm. That is, the film thickness of the entire piezoelectric laminated film was 3550 nm.

The first and second piezoelectric thin films were formed by RF magnetron sputtering. A 6-inch-diameter sintered compact target (composition molar ratio Pb:Zr:Ti=1.20:0.53:0.47) of stoichiometric structure PZT prepared by adding approximately 20 mol% of PbO in excess was used as a target. Film-forming conditions are as follows. In other words, first, in the film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film and the orientation control film are formed on the surface is preheated and maintained at a temperature of 580°C, and a mixed gas of argon and oxygen is used. As the sputtering gas, the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen=38:2, the flow rate is 40 ml per minute, and the plasma generation power is 3 kW. 1 Piezoelectric thin film formation. Then, the film formation was stopped, and the mixing ratio of the sputtering gas was immediately changed to argon:oxygen = 79:1, and other conditions were kept constant, and the second piezoelectric thin film was formed in 2900 seconds.

A platinum (Pt) thin film was used as the second electrode film. The platinum thin film was formed on the second piezoelectric thin film by RF sputtering.

In addition, in order to accurately obtain the film thickness, (111) orientation, composition and cross-sectional structure of the orientation control film and the first piezoelectric thin film shown in FIG. 21(b), after forming the orientation control film and the first piezoelectric thin film, A laminated film that stops film formation is also formed at the same time as the electrode thin film. Regarding this sample, after observing the surface by a scanning electron microscope, analyzing by X-ray diffraction, and analyzing the composition by an X-ray microanalyzer, the sample was destroyed, and analyzed by a scanning electron microscope. The cross section was observed.

In addition, in order to accurately obtain the film thickness, (111) orientation, composition, and cross-sectional structure of the second piezoelectric thin film shown in FIG. Film-forming laminated film. Regarding this sample, as above, after observing the surface with a scanning electron microscope, analyzing with an X-ray diffraction, and analyzing the composition of an X-ray microanalyzer, the sample is destroyed, and the The section was observed with a type electron microscope.

Then, using the structure shown in FIG. 21( b ) as a sample, the composition analysis from the surface to the depth direction of the piezoelectric multilayer film was performed by Auger spectroscopic analysis. Furthermore, the cross-section of the piezoelectric laminated film was observed with a scanning electron microscope. FIG. 23( a ) shows an enlarged electron micrograph of the cross-section of the piezoelectric laminated film, and FIG. 23( b ) shows a partially enlarged view of FIG. 23( a ).

As a result of the above analysis and the above observation, the iridium electrode is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm. The orientation control film and the first and second piezoelectric thin films exist as a particle aggregate of a columnar structure in continuous contact with each other. The orientation control film has a film thickness of 40 nm. The first piezoelectric thin film has a film thickness of 50 nm, and the average cross-sectional diameter of the columnar particles is 40 nm. The second piezoelectric thin film has a film thickness of 3500 nm, and the average cross-sectional diameter of the columnar particles is 160 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 22.2.

(Angstrom)到的X射线衍射范围中，(111)峰值强度与属于薄膜的全峰值强度的合计的百分率。也就是，结晶取向率为属于(111)的峰值强度，与PLT薄膜、PLZT薄膜、PZT薄膜的X射线衍射图案的(001)、(100)、(010)、(110)、(011)、(101)、(111)等各结晶面的峰值强度的合计的比例的百分率。As a result of X-ray diffraction analysis, it was found that the orientation control film and the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the orientation control film was 50%. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 70%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 98%. Here, the (111) crystal orientation ratio of the PLT-based orientation control film and the PZT-based piezoelectric thin film obtained from the reflection intensity of each crystal plane of the diffraction pattern by the X-ray diffraction method is defined as

(Angstrom) to In the X-ray diffraction range of , the percentage of the (111) peak intensity and the total peak intensity belonging to the film. That is, the crystal orientation rate belongs to the peak intensity of (111), and the X-ray diffraction pattern of the PLT film, PLZT film, and PZT film (001), (100), (010), (110), (011), (101), (111), etc. The percentage of the ratio of the total peak intensity of each crystal plane.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the composition of the orientation control film is Pb:La:Ti=1.05:0.10:0.98, and the compositions of the first and second piezoelectric thin films are Pb:Zr: Ti=1.15:0.53:0.47 and Pb:Zr:Ti=1.10:0.53:0.47. That is, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and the compositions of Zr and Ti are between the first and second piezoelectric thin films. 2 Piezoelectric thin films remain unchanged, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film. In other words, the first and second piezoelectric thin films are aggregates of columnar particles whose crystal growth direction is directed from one side in the thickness direction of the piezoelectric multilayer film to the other.

Then, a triangular wave voltage of 0V to -80V was applied between the first and second electrode films 2 and 6 of the piezoelectric element 20 through the lead wires 9a and 9b, and the piezoelectric body was measured using a laser Doppler vibration displacement measurement device. The displacement of the front end of the component 20 moving up and down in the Z direction. FIG. 24 is a graph showing the displacement amount of the tip of the piezoelectric body element 20 moving up and down in the Z direction when a voltage having a frequency of 2 kHz is applied. As shown in FIG. 24 , when a voltage of 0 V to -80 V was applied, the tip of the piezoelectric element 20 was displaced by a maximum of 38.0 μm. The driving state of the piezoelectric body element 20 was inspected after driving 100 million times (driving time: 13.9 hours) and 1 billion times (driving time: 138.9 hours) by the triangular wave voltage. At the same time, it was observed with an optical microscope. Exterior. After driving 1 billion times, the maximum displacement was 38.0 μm, and neither film peeling nor cracking occurred in the piezoelectric element 20 .

(Ninth embodiment)

A heat-resistant Pyrex (registered trademark) glass was used for the substrate, and a platinum (Pt) thin film with a thickness of 150 nm was used for the first electrode film. The platinum thin film was formed by using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =15 : 1) As the sputtering gas, the total gas pressure was kept at 0.25 Pa, a platinum target was used as the first target, 200 W of high-frequency power was applied, and sputtering was performed for 1080 seconds.

A (111) preferentially oriented PLZT thin film having a thickness of 50 nm was used as the orientation control film. The PLZT thin film is formed by heating the substrate on which the first electrode film is formed on the surface at a temperature of 550°C in advance in the same 3-dimensional RF magnetron sputtering device, using a mixture of argon and oxygen. Gas (gas volume ratio Ar:O ₂ =25:0.5) is used as the sputtering gas, the total gas pressure is kept at 1.0Pa, and a 4-inch PLZT with a stoichiometric structure prepared by adding about 20 mol% of PbO in excess is used. A diameter sintered body target (composition molar ratio Pb:La:Zr:Ti=1.15:0.05:0.10:0.90) was used as the second target, and 250W of high-frequency power was applied and sputtering was performed for 3600 seconds.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is composed of a (111) preferentially oriented PZT thin film with a thickness of 100 nm, and the second piezoelectric thin film is 2 The piezoelectric thin film is composed of a (111)-oriented PZT thin film with a thickness of 5000 nm. In other words, the film thickness of the piezoelectric laminated film was set to 5100 nm.

As in the eighth embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering apparatus. A 6-inch-diameter sintered body target (composition molar ratio Pb:Zr:Ti=1.10:0.50:0.50) of stoichiometric structure PZT prepared by adding about 10 mol% of PbO in excess was used as a target. Film-forming conditions are as follows. In other words, first, in the film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film and the orientation control film are formed on the surface is preliminarily heated and maintained at a temperature of 550°C, and a mixed gas of argon and oxygen is used. As the sputtering gas, the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen=79:1, the flow rate is 40 ml per minute, and the plasma generation power is 2 kW. 1 Piezoelectric thin film formation. Then, the film formation was stopped, the substrate temperature was 590° C., the plasma generation power was 3 kW, and other conditions were kept constant, and the second piezoelectric thin film was formed for 3800 seconds.

As a result of the same analysis and observation as in the eighth example, the platinum electrode was an aggregate of columnar particles with an average cross-sectional diameter of 30 nm. The orientation control film and the first and second piezoelectric thin films exist as a particle aggregate of a columnar structure in continuous contact with each other. The orientation control film has a film thickness of 50 nm. The first piezoelectric thin film has a film thickness of 100 nm, and the average cross-sectional diameter of the columnar particles is 40 nm. The second piezoelectric thin film has a film thickness of 5000 nm, and the average cross-sectional diameter of the columnar particles is 85 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 60.0.

As a result of X-ray diffraction analysis, it was found that the orientation control film and the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the orientation control film was 60%. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 70%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 95%.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the composition of the orientation control film is Pb:La:Zr:Ti=1.08:0.05:0.12:0.88, and the compositions of the first and second piezoelectric thin films are respectively Pb:Zr:Ti=1.15:0.51:0.49 and Pb:Zr:Ti=1.00:0.51:0.49. That is, like the eighth embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the eighth example, a triangular wave voltage of 0V to -80V at a frequency of 2kHz was applied to the piezoelectric element 20 of this example, and the vertical displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 35.2 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

(the tenth embodiment)

A mirror-finished heat-resistant stainless steel plate was used as the substrate, and an alloy thin film composed of iridium (Ir) with a thickness of 110 nm including titanium (Ti) was used as the first electrode film. The alloy thin film is formed by heating the substrate at a temperature of 400° C. in advance in a 3-dimensional RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =16 : 1) As the sputtering gas, the total gas pressure was kept at 0.25 Pa, an iridium target was used as the first target, and a titanium target was used as the second target, and 200W and 60W high-frequency electricity were applied respectively, and sputtering was performed for 960 seconds. In addition, the purpose of adding titanium to iridium is to improve the adhesion with the substrate, and even if titanium is not added, the characteristics of the piezoelectric element will not be affected.

A (111) preferentially oriented PLT film with a thickness of 20 nm was used as the orientation control film. The PLT thin film is formed by heating the substrate on which the first electrode film is formed on the surface at a temperature of 600°C in the same 3-dimensional RF magnetron sputtering device, using a mixture of argon and oxygen. Gas (gas volume ratio Ar:O ₂ =25:0.2) was used as the sputtering gas, the total gas pressure was maintained at 1.0 Pa, and a 4-inch PLT with a stoichiometric structure prepared by adding about 10 mol% of PbO in excess was used. A diameter sintered compact target (composition molar ratio Pb:La:Ti=0.90:0.20:1.0) was used as the third target, and 250W of high-frequency power was applied, and sputtering was performed for 1200 seconds.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is made of (111) preferential orientation with a thickness of 100 nm and added with 10 mol % of magnesium (Mg ), and the second piezoelectric thin film is composed of a (111)-oriented (PZT+Mg) film with a thickness of 3900 nm. In other words, the film thickness of the piezoelectric laminated film was set to 4000 nm.

As in the eighth embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering apparatus. A 6-inch-diameter sintered body target using a stoichiometric structure of lead zirconate titanate (PZT+Mg) prepared by adding about 10 mol% of PbO in excess and adding 10 mol% of magnesium (Mg) (composition molar ratio Pb: Zr:Ti:Mg=1.10:0.60:0.40:0.10) as a target. Film-forming conditions are as follows. In other words, first, in the film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film and the orientation control film are formed on the surface is preheated and maintained at a temperature of 570°C, and a mixed gas of argon and oxygen is used. As the sputtering gas, the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen = 38: 2, the flow rate is 40 ml per minute, and the plasma generation power is 3 kW. 1 Piezoelectric thin film formation. Then, the film formation was stopped, and the mixing ratio of the sputtering gas was immediately changed to argon:oxygen=79:1, and other conditions were kept constant, and the second piezoelectric thin film was formed for 2500 seconds.

As a result of the same analyzes and observations as in the eighth embodiment, the first electrode film is composed of an iridium thin film containing 1 mol % of titanium, and is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm. The orientation control film and the first and second piezoelectric thin films exist as a particle aggregate of a columnar structure in continuous contact with each other. The orientation control film has a film thickness of 20 nm. The first piezoelectric thin film has a film thickness of 100 nm, and the average cross-sectional diameter of the columnar particles is 70 nm. The second piezoelectric thin film has a film thickness of 3900 nm, and the average cross-sectional diameter of the columnar particles is 200 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 20.0.

As a result of X-ray diffraction analysis, it was found that the orientation control film and the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the orientation control film was 70%. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 80%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 100%.

As a result of compositional analysis of positive ions by an X-ray microanalyzer, the composition of the orientation control film is Pb:La:Ti=0.85:0.22:0.95, and the compositions of the first and second piezoelectric thin films are Pb:Zr: Ti:Mg=1.05:0.60:0.40:0.09 and Pb:Zr:Ti:Mg=1.00:0.60:0.40:0.10. That is, like the eighth embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the eighth example, a triangular wave voltage of 0V to -80V at a frequency of 2kHz was applied to the piezoelectric element 20 of this example, and the vertical displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 38.3 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

(Eleventh embodiment)

A mirror-polished ceramic material (alumina) was used for the substrate, and an alloy thin film made of ruthenium (Ru) containing nickel (Ni) and having a thickness of 120 nm was used for the first electrode film. The alloy thin film is formed by heating the substrate at a temperature of 400° C. in advance in a 3-dimensional RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =16 : 1) As the sputtering gas, the total gas pressure was kept at 0.25 Pa, a ruthenium target was used as the first target, a nickel target was used as the second target, 200W and 60W high-frequency electricity were respectively applied, and sputtering was performed for 960 seconds. In addition, the purpose of adding nickel to ruthenium is to improve the adhesion with the substrate, and even if nickel is not added, the characteristics of the piezoelectric element will not be affected.

A (111) preferentially oriented PLZT thin film having a thickness of 60 nm was used as the orientation control film. The PLZT thin film is formed by heating the substrate on which the first electrode film is formed on the surface at a temperature of 650°C in the same 3-dimensional RF magnetron sputtering device, using a mixture of argon and oxygen. Gas (gas volume ratio Ar:O ₂ =25:1.0) is used as the sputtering gas, the total gas pressure is kept at 0.5Pa, and a 4-inch PLZT with a stoichiometric structure prepared by adding about 20 mol% of PbO in excess is used. A diameter sintered compact target (composition molar ratio Pb:La:Zr:Ti=1.10:0.10:0.20:0.80) was used as the third target, and 250W of high-frequency power was applied and sputtering was performed for 3600 seconds.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is made of (111) preferentially oriented 5 nm thick manganese (Mn ), and the second piezoelectric film is composed of a (111)-oriented (PZT+Mn) film with a thickness of 2500 nm. In other words, the film thickness of the piezoelectric laminated film was set to 2505 nm.

As in the eighth embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering apparatus. A 6-inch-diameter sintered body target using PZT with a stoichiometric structure prepared by adding approximately 20 mol% of PbO in excess and adding 5 mol% of manganese (Mn) (composition molar ratio Pb:Zr:Ti:Mn=1.20: 0.40:0.60:0.05) as the target. Film-forming conditions are as follows. In other words, first, in a film-forming chamber equipped with the above-mentioned (PZT+Mn) target, the substrate on which the first electrode film and the orientation control film are formed on the surface is preliminarily heated and maintained at a temperature of 550° C., using argon and The mixed gas of oxygen is as sputtering gas, and this gas pressure is 0.2Pa, and this mixing ratio is argon: oxygen=79: 1, makes its flow rate be 40ml per minute, makes plasma generation power be 2kW, uses under these conditions The first piezoelectric thin film was formed in 5 seconds. Then, the film formation was stopped, the substrate temperature was set at 580° C., the plasma generation power was set at 3 kW, and other conditions were kept constant, and the second piezoelectric thin film was formed for 2000 seconds.

As a result of the same analyzes and observations as in the eighth embodiment, the first electrode film is composed of a ruthenium thin film containing 4 mol% nickel and is an aggregate of columnar particles with an average cross-sectional diameter of 25 nm. The orientation control film and the first and second piezoelectric thin films exist as a particle aggregate of a columnar structure in continuous contact with each other. The orientation control film has a film thickness of 60 nm. The first piezoelectric thin film has a film thickness of 5 nm, and the average cross-sectional diameter of the columnar particles is 40 nm. The second piezoelectric thin film has a film thickness of 2500 nm, and the average cross-sectional diameter of the columnar particles is 60 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 41.7.

As a result of X-ray diffraction analysis, it was found that the orientation control film and the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the orientation control film was 75%. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 80%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 99%.

As a result of compositional analysis of positive ions by an X-ray microanalyzer, the composition of the orientation control film is Pb:La:Zr:Ti=1.05:0.10:0.22:0.78, and the compositions of the first and second piezoelectric thin films are respectively Pb:Zr:Ti:Mn=1.10:0.40:0.60:0.05 and Pb:Zr:Ti:Mn=1.05:0.40:0.60:0.05. That is, like the eighth embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the eighth example, a triangular wave voltage of 0V to -80V at a frequency of 2kHz was applied to the piezoelectric element 20 of this example, and the vertical displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 32.7 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

(12th embodiment)

Silicon was used for the substrate, and a palladium (Pd) thin film with a thickness of 120 nm was used for the first electrode film. The palladium thin film was formed by heating the substrate at a temperature of 500° C. in advance in a 3-dimensional RF magnetron sputtering device, using a mixed gas of argon and oxygen (gas volume ratio Ar:O ₂ =16 : 1) As the sputtering gas, the total gas pressure was kept at 0.25 Pa, a palladium target was used as the first target, 200 W of high-frequency electricity was applied, and sputtering was performed for 960 seconds.

A (111) preferentially oriented PLT film with a thickness of 40 nm was used as the orientation control film. The PLT thin film is formed by heating the substrate on which the first electrode film is formed on the surface at a temperature of 600°C in the same 3-dimensional RF magnetron sputtering device, using a mixture of argon and oxygen. Gas (gas volume ratio Ar:O ₂ =25:0.2) was used as the sputtering gas, the total gas pressure was maintained at 1.0 Pa, and a 4-inch PLT with a stoichiometric structure prepared by adding about 20 mol% of PbO in excess was used. A diameter sintered compact target (composition molar ratio Pb:La:Ti=0.90:0.30:1.0) was used as the second target, and 250W of high-frequency power was applied and sputtering was performed for 2400 seconds.

The piezoelectric laminated film is composed of a first piezoelectric thin film and a second piezoelectric thin film, wherein the first piezoelectric thin film is composed of a (111) preferentially oriented PZT thin film with a thickness of 80 nm, and the second piezoelectric thin film is The piezoelectric thin film is composed of a (111)-oriented PZT thin film with a thickness of 4500 nm. In other words, the film thickness of the piezoelectric laminated film was set to 4580 nm.

As in the eighth embodiment, the first and second piezoelectric thin films were formed using an RF magnetron sputtering apparatus. A 6-inch-diameter sintered body target (composition molar ratio Pb:Zr:Ti=1.20:0.58:0.42) of stoichiometric structure PZT prepared by adding approximately 20 mol% of PbO in excess was used as a target. Film-forming conditions are as follows. In other words, first, in the film-forming chamber equipped with the above-mentioned PZT target, the substrate on which the first electrode film and the orientation control film are formed on the surface is preheated and maintained at a temperature of 580°C, and a mixed gas of argon and oxygen is used. As the sputtering gas, the gas pressure is 0.2 Pa, the mixing ratio is argon: oxygen = 38: 2, the flow rate is 40 ml per minute, and the plasma generation power is 3 kW. 1 Piezoelectric thin film formation. Then, the film formation was stopped, and the mixing ratio of the sputtering gas was immediately changed to argon:oxygen = 79:1, and other conditions were kept constant, and the second piezoelectric thin film was formed in 3700 seconds.

As a result of the same analyzes and observations as in the eighth embodiment, the first electrode film is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm. The orientation control film and the first and second piezoelectric thin films exist as a particle aggregate of a columnar structure in continuous contact with each other. The orientation control film has a film thickness of 40 nm. The first piezoelectric thin film has a film thickness of 80 nm, and the average cross-sectional diameter of the columnar particles is 50 nm. The second piezoelectric thin film has a film thickness of 4500 nm, and the average cross-sectional diameter of the columnar particles is 150 nm. The ratio of the thickness of the piezoelectric laminated film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film was 30.5.

As a result of X-ray diffraction analysis, it was found that the orientation control film and the first and second piezoelectric thin films had a perovskite crystal structure. The (111) crystal orientation of the formation surface of the orientation control film was 55%. The (111) crystal orientation of the formation surface of the first piezoelectric thin film was 70%. The (111) crystal orientation ratio of the formation surface of the second piezoelectric thin film was 98%.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the composition of the orientation control film is Pb:La:Ti=0.82:0.28:0.98, and the compositions of the first and second piezoelectric thin films are Pb:Zr: Ti=1.10:0.58:0.42 and Pb:Zr:Ti=1.05:0.58:0.42. That is, like the eighth embodiment, the first and second piezoelectric thin films are PZT films with a perovskite crystal structure in which the (111) axis is preferentially oriented in a direction perpendicular to the substrate surface, and Zr and Ti The composition of Pb is constant in the first and second piezoelectric thin films, and the composition of Pb is greater in the first piezoelectric thin film than in the second piezoelectric thin film.

As in the eighth example, a triangular wave voltage of 0V to -80V at a frequency of 2kHz was applied to the piezoelectric element 20 of this example, and the vertical displacement of the tip of the piezoelectric element 20 in the Z direction was measured. The maximum displacement of the tip of the piezoelectric element 20 was 31.5 μm, and the maximum displacement remained unchanged even after driving 1 billion times, and no film peeling or cracks occurred in the piezoelectric element 20 .

In addition, in the eighth embodiment to the twelfth embodiment, three-dimensional oxides to which Pb, Zr, and Ti were added, and PZT thin films to which Mg and Mn were added were used as piezoelectric laminated films, and it is also possible to use If the PZT film of La (that is, the PLZT film) and the PZT film containing ions such as Nb and Mg are used, the same as the eighth embodiment to the twelfth embodiment can be obtained if an oxide thin film with a perovskite crystal structure is used. piezoelectric laminated film.

(comparative example 3)

For comparison with the eighth to twelfth examples, the following piezoelectric elements were formed.

In the eighth embodiment, only the second piezoelectric thin film is formed on the orientation control film instead of the piezoelectric multilayer film, and other formations are performed in the same manner as in the eighth embodiment.

Regarding the sample of this comparative example, as above, the surface was observed by a scanning electron microscope, analyzed by X-ray diffraction, and analyzed by an X-ray microanalyzer. Its cross-section was observed with an electron microscope.

As a result of the above analyzes and the above observations, the orientation control film and the piezoelectric thin film of this comparative example exist as a particle aggregate with a columnar structure. The piezoelectric thin film has a film thickness of 3500nm, and the average cross-sectional diameter of the columnar particles is 230nm. The ratio of the length of the columnar particles of the piezoelectric thin film to the average cross-sectional diameter of the columnar particles of the piezoelectric thin film was 15.2.

As a result of X-ray diffraction analysis, both the orientation control film and the piezoelectric thin film of this comparative example have a perovskite crystal structure. The (111) crystal orientation ratio of the formation surface of the orientation control film was 50%. The (111) crystal orientation ratio of the formation surface of the piezoelectric thin film was 65%.

As a result of compositional analysis of positive ions by an X-ray microanalyzer, the composition of the orientation control film of this comparative example is Pb:La:Ti=1.05:0.10:0.98, and the composition of the piezoelectric thin film is Pb:Zr:Ti=1.05:0.53 : 0.47.

As a result of composition analysis from the surface of the piezoelectric thin film to the depth direction by Auger spectroscopy, the composition distribution of Zr and Ti was constant from the interface with the second electrode film to the interface with the orientation control film.

That is, this comparative example is the same as the eighth embodiment in that the piezoelectric thin film is a PZT film with a perovskite crystal structure grown as an aggregate of columnar particles in a direction perpendicular to the substrate surface. However, the average cross-sectional diameter of the columnar particles of the piezoelectric thin film is larger than that of the eighth example, and the (111) crystal orientation ratio of the piezoelectric thin film is smaller than that of the eighth example.

As in the eighth example, a triangular wave voltage with a frequency of 2 kHz and 0 V to -80 V was applied to the piezoelectric element of this comparative example, and the displacement amount of the tip of the piezoelectric element 20 moving up and down in the Z direction was measured. The tip of the piezoelectric element was displaced by a maximum of 20.0 μm. Then, the reciprocating drive by the triangular wave voltage was carried out. After 100 million times of driving, the inspection of the driving state and the observation of the appearance with an optical microscope were performed. The maximum displacement decreased to 5.5 μm, and the first electrode film and orientation Partial membrane peeling occurred between the control membranes.

(comparative example 4)

For comparison with the eighth to twelfth examples, the following piezoelectric elements were produced.

In the twelfth embodiment, only the second piezoelectric thin film is directly formed on the first electrode film made of a palladium thin film instead of the orientation control film and the piezoelectric laminated film, and the rest is exactly the same as the twelfth embodiment.

Regarding the sample of this comparative example, as above, the surface was observed by a scanning electron microscope, analyzed by X-ray diffraction, and analyzed by an X-ray microanalyzer. Its cross-section was observed with an electron microscope.

As a result of the above analysis and the above observation, the piezoelectric thin film of this comparative example exists as an aggregate of particles having a columnar structure. The piezoelectric thin film has a film thickness of 4500nm, and the average cross-sectional diameter of the columnar particles is 300nm. The ratio of the length of the columnar particles of the piezoelectric thin film to the average cross-sectional diameter of the columnar particles of the piezoelectric thin film was 15.0.

As a result of X-ray diffraction analysis, the piezoelectric thin film of this comparative example has a perovskite crystal structure. The (111) crystal orientation ratio of the piezoelectric thin film was 30%.

As a result of composition analysis of positive ions by an X-ray microanalyzer, the composition of the piezoelectric thin film of this comparative example was Pb:Zr:Ti=1.05:0.53:0.47.

As a result of composition analysis from the surface of the piezoelectric thin film to the depth direction by Auger spectroscopy, the composition distribution of Zr and Ti was constant from the interface with the second electrode film to the interface with the first electrode film. The Pb composition is somewhat reduced (about one-twentieth of the Pb composition of the entire piezoelectric thin film) within a range of 10 nm from the interface with the first electrode film. This phenomenon cannot be observed with the precision of the Auger spectroscopic analysis, and it is considered to be caused by the diffusion of only a little Pb composition into the first electrode film.

That is, this comparative example is the same as the twelfth embodiment in that the piezoelectric thin film is a PZT film with a perovskite crystal structure grown as an aggregate of columnar particles in a direction perpendicular to the substrate surface. However, the difference from the twelfth embodiment is that the average cross-sectional diameter of the columnar particles of the piezoelectric thin film is larger than that of the twelfth embodiment, and the (111) crystal orientation ratio of the piezoelectric thin film is smaller than that of the twelfth embodiment, which is different from that of the first embodiment. The Pb composition near the interface of the electrode film is the same as the Pb composition of the entire piezoelectric thin film, and the Pb composition at the interface with the first electrode film is somewhat reduced.

As in the twelfth embodiment, a triangular wave voltage with a frequency of 2 kHz and 0 V to -80 V was applied to the piezoelectric element of this comparative example, and the displacement amount of the tip of the piezoelectric element moving up and down in the Z direction was measured. The tip of the piezoelectric element was displaced by a maximum of 12.0 μm. Then, the reciprocating drive by the triangular wave voltage was carried out, and after driving 1 billion times, the result of inspection of the driving state and observation of the appearance with an optical microscope was carried out, and the driving was stopped. Membrane peeling occurred.

(Embodiment 6)

This embodiment is an inkjet head including the piezoelectric element according to Embodiment 5 of the present invention. Hereinafter, this inkjet head will be described.

The inkjet head 201 according to Embodiment 6 of the present invention is composed of ten ink discharge elements 202 and a drive power supply element 203 connected to the individual electrode 33 of each ink discharge element 202 for driving each ink discharge element 202 . The ink discharge element 202 includes an actuator unit B having the same piezoelectric element as the piezoelectric element 20 of the fifth embodiment. Other points are almost the same as in Embodiment 2 (see FIG. 6 ).

A more specific embodiment of the actuator unit B will be described below.

(13th embodiment)

The actuator unit B will be described with reference to FIG. 25 .

25 is a view corresponding to the sectional view taken along line VIII-VIII in FIG. 7 of the actuator unit B according to the thirteenth example of the sixth embodiment. As shown in FIG. 25, the actuator part B has: an individual electrode (first electrode film) ₃₃ made of an iridium (Ir) thin film with a thickness of 100 nm; An orientation control film 41 composed of a PLT film _with a thickness of 40 nm represented by 0.10 Ti 1.00 O ₃ ; and _a PZT film with a thickness of 50 nm represented by Pb _1.15 Zr _0.53 Ti _0.48 O ₃ directly below the orientation control film 41 The first piezoelectric thin film 42; the second piezoelectric thin film 43 located directly below the first piezoelectric thin film 42 and made of a PZT thin film represented by Pb _1.10 Zr _0.53 Ti _0.47 O ₃ with a thickness of 3500 nm; The second electrode film 44 directly below the second piezoelectric thin film 43 is composed of a platinum thin film with a thickness of 100 nm; The vibrating body layer 45. The vibrator layer 45 is displaced and vibrated by the piezoelectric effect of the first and second piezoelectric thin films 42 and 43 . The second electrode film 44 and the vibrator layer 45 are shared between the pressure chambers 32 of the respective ink discharge elements 202 . The orientation control film 41 , and the first piezoelectric thin film 42 and the second piezoelectric thin film 43 are processed to have the same shape as the individual electrodes 33 . On the second electrode film 44, around the laminated film composed of the individual electrode 33, the orientation control film 41, the first piezoelectric thin film 42, and the second piezoelectric thin film 43, a layer having the same thickness as the above-mentioned laminated film is provided. An electrically insulating organic film 46 made of poly(imide) resin. On the electrically insulating organic film 46, a lead-out electrode film 47 connected to the individual electrode 33 and composed of a lead-shaped metal thin film with a thickness of 100 nm is provided. The individual electrodes 33 , the orientation control film 41 , the piezoelectric multilayer film composed of the first and second piezoelectric thin films 42 and 43 , and the second electrode film 44 constitute a piezoelectric element. This piezoelectric body element is the same as the piezoelectric body element 20 of Embodiment 5, and therefore, it is possible to obtain an actuator unit B with high characteristics.

Hereinafter, a method of manufacturing the actuator unit B will be described.

26 and 27 are process diagrams showing the manufacturing method of the actuator unit B. As shown in FIG. First, on a silicon substrate 51 with a length of 20 mm, a width of 20 mm, and a thickness of 0.3 mm, a first electrode film 52, an orientation control film 53, and a first piezoelectric bulk thin film 54 , second piezoelectric thin film 55 and second electrode film 44 . Accordingly, the structure 56 shown in FIG. 26( a ) can be obtained.

Next, as shown in FIG. 26(b), a vibrator layer 45 made of a chromium (Cr) thin film with a thickness of 3500 nm was formed on the structure 56 by RF sputtering at room temperature.

Next, as shown in FIG. 26(c), the vibrator layer 45 is attached to the glass pressure chamber member 58 with an acrylic resin adhesive 57. The pressure chamber member 58 is provided so as to face the vibrating body layer 45 , and the adhesive 57 is interposed between the pressure chamber member 58 and the vibrating body layer 45 .

Next, as shown in FIG. 26(d), the silicon substrate 51 was removed by dry etching with SF ₆ gas using a plasma reactive etching apparatus.

Next, as shown in FIG. 26(e), using a photoresist resin film 59, a laminated film composed of a first electrode film 52, an orientation control film 53, a first piezoelectric thin film 54, and a second piezoelectric thin film 55 is formed. The non-etched portion of , was correctly patterned into an elliptical pattern with a minor axis of 180 μm and a major axis of 380 μm. Then, etching was performed using dry etching using argon (Ar) gas and wet etching using weak hydrofluoric acid. In this way, it is possible to obtain a photoresist pattern processed as shown in FIG. 27(a), which has individualized individual electrodes 33, an orientation control film 41, a first piezoelectric thin film 42, and a second piezoelectric thin film. A laminated film actuator structure composed of a thin film 43 . Then, as shown in FIG. 27(b), the photoresist resin film 59 is treated with a resist stripper to remove it.

Next, as shown in FIG. 27(c), an electrically insulating organic film 46 is formed on the second electrode film 44 by printing. Then, as shown in FIG. 27(d), a lead electrode film 47 is formed on the electrically insulating organic film 46 by the DC sputtering method. In this way, the actuator unit B shown in FIG. 25 can be obtained.

Thirty ink discharge elements 202 were manufactured by the manufacturing method shown in this example. A sinusoidal waveform voltage of 0 V to -60 V at a frequency of 200 Hz was applied between the two electrode films 33 and 44 of these ink ejection elements 202, and the above-mentioned driving conditions were checked. No failure occurred in any of the ink discharge elements 202 even after driving 1 billion times.

Using ten of these ink discharge elements 202, the inkjet head 201 shown in FIG. 6 was fabricated. Using this inkjet head 201, the same effect as that of the sixth embodiment can be obtained.

(14th embodiment)

Referring to FIG. 28, an actuator unit B having a structure different from that of the thirteenth embodiment will be described.

FIG. 28 is a view corresponding to the sectional view taken along line VIII-VIII in FIG. 7 of the actuator unit B according to the fourteenth example of the sixth embodiment. As shown in FIG. 28, the actuator part B has: an individual electrode (second electrode film ₎ 33 made of a platinum (Pt) thin film with a thickness of 100 nm; _0.58 Ti _0.42 O ₃ is a second piezoelectric thin film 43 composed of a PZT thin film with a thickness of 4500 nm; the thickness immediately below the second piezoelectric thin film 43 and represented by Pb _1.10 Zr _0.58 Ti _0.42 O ₃ is A first piezoelectric thin film 42 made of a PZT thin film of 80 nm; an orientation control film made of a PLT thin film having a thickness of 40 nm represented by Pb _0.09 Zr _0.30 Ti _1.00 O ₃ located directly below the first piezoelectric thin film 42 41; a first electrode film 52 made of palladium with a thickness of 200 nm directly below the orientation control film 41; and a silicon oxide (SiO ₂ ) film with a thickness of 5000 nm directly below the first electrode film 52 The vibrating body layer 45 is formed. The vibrator layer 45 is displaced and vibrated by the piezoelectric effect of the first and second piezoelectric thin films 42 and 43 . The first electrode film 52 and the vibrator layer 45 are shared between the pressure chambers 32 of the respective ink discharge elements 202 . The orientation control film 41 , and the first piezoelectric thin film 42 and the second piezoelectric thin film 43 are processed to have the same shape as the individual electrodes 33 . On the first electrode film 52, around the laminated film composed of the individual electrode 33, the orientation control film 41, the first piezoelectric thin film 42, and the second piezoelectric thin film 43, a film having the same thickness as the above-mentioned laminated film is provided. An electrically insulating organic film 46 made of poly(imide) resin. On the electrically insulating organic film 46, a lead-out electrode film 47 connected to the individual electrode 33 and composed of a lead-shaped metal thin film with a thickness of 100 nm is provided. The individual electrodes 33 , the orientation control film 41 , the piezoelectric multilayer film composed of the first and second piezoelectric thin films 42 and 43 , and the first electrode film 52 constitute a piezoelectric element. This piezoelectric body element is the same as the piezoelectric body element 20 of Embodiment 5, and thus, it is possible to obtain an actuator unit B with high characteristics.

Hereinafter, a method of manufacturing the actuator unit B will be described.

29 and 30 are process diagrams showing a method of manufacturing the actuator unit B. As shown in FIG. First, the vibrating body layer 45 is formed on a silicon substrate 51 (pressure chamber substrate) having a length of 20 mm, a width of 20 mm, and a thickness of 0.3 mm. Then, on the vibrating body layer 45, the same method as in the twelfth embodiment of the fifth embodiment is formed. As in the example, the first electrode film 52 , the orientation control film 53 , the first piezoelectric thin film 54 , the second piezoelectric thin film 55 , and the second electrode film 44 are laminated in this order. In this way, the structure 56 shown in FIG. 29( a ) can be obtained.

Next, as shown in FIG. 29(b), using a photoresist resin film 59, the laminated film composed of the second electrode film 44, the orientation control film 53, the first piezoelectric thin film 54, and the second piezoelectric thin film 55 is laminated. The non-etched portion of , was correctly patterned into an elliptical pattern with a minor axis of 180 μm and a major axis of 380 μm.

Next, etching was performed using dry etching using argon (Ar) gas and wet etching using weak hydrofluoric acid. In this way, it is possible to obtain a photoresist pattern processed as shown in FIG. 29(c), which has individualized individual electrodes 33, an orientation control film 41, a first piezoelectric thin film 42, and a second piezoelectric A laminated film actuator structure composed of a thin film 43 . Then, as shown in FIG. 29(d), the photoresist resin film 59 is treated with a resist stripper to remove it. Then, as shown in FIG. 30(a), an electrically insulating organic film 46 is formed on the first electrode film 52 by a printing method.

Next, as shown in FIG. 30( b ), a part of the silicon substrate 51 was removed by dry etching with SF ₆ gas using a plasma reactive etching device to form a pressure chamber 32 .

Next, as shown in FIG. 30(c), a lead electrode film 47 is formed on the electrically insulating organic film 46 by DC sputtering. In this way, the actuator unit B shown in FIG. 28 can be obtained.

Thirty ink discharge elements 202 were manufactured by the manufacturing method shown in this example. A sinusoidal waveform voltage of 0 V to -60 V at a frequency of 200 Hz was applied between the two electrode films 33 and 52 of these ink ejection elements 202, and the above-mentioned driving conditions were checked. No failure occurred in any of the ink discharge elements 202 even after driving 1 billion times.

Using ten of these ink discharge elements 202, the inkjet head 201 shown in FIG. 6 was fabricated. Using this inkjet head 201, the same effect as that of the sixth embodiment can be obtained.

(Embodiment 7)

This embodiment is an inkjet recording device including the inkjet head according to Embodiment 6 of the present invention. Hereinafter, this inkjet recording device will be described.

The ink jet recording device 81 according to the seventh embodiment of the present invention includes the ink jet head 201 according to the sixth embodiment. Other points are almost the same as Embodiment 3 (see FIG. 14 ).

According to this embodiment, the same effect as that of Embodiment 3 can be obtained.

(Embodiment 8)

This embodiment is an angular velocity sensor including the piezoelectric element according to Embodiment 5 of the present invention. Hereinafter, this angular velocity sensor will be described.

31 and 32 are schematic diagrams and cross-sectional views of an angular velocity sensor 400 according to Embodiment 8 of the present invention.

The angular velocity sensor 400 includes a substrate 500 made of a silicon wafer with a thickness of 0.3 mm. This substrate 500 has a fixed portion 500a and a pair of vibrating portions 500b extending from the fixed portion 500a in a predetermined direction (the direction in which the center axis of rotation of the detected angular velocity extends. In this embodiment, the Y direction in FIG. 31 ). , 500b. These fixed part 500a and a pair of vibrating parts 500b, 500b are in the shape of a tuning fork when viewed from the thickness direction of the substrate 500 (Z direction in FIG. 500b extend parallel to each other in a state of being aligned in the width direction. In addition, the substrate 500 may also be a glass substrate, a metal substrate, a ceramic substrate, or the like.

A first electrode film 502, an orientation control film 503, a first piezoelectric thin film 504, a second piezoelectric thin film 504, and a second piezoelectric thin film 504 are laminated in this order on each vibrating portion 500b of the substrate 500 and on the vibrating portion 500b side of the fixed portion 500a. Thin film 505 and second electrode film 506. The first electrode film 502 , the orientation control film 503 , the piezoelectric multilayer film composed of the first and second piezoelectric thin films 504 and 505 , and the second electrode film 506 constitute a piezoelectric element. This piezoelectric element is the same as the piezoelectric element 20 of the fifth embodiment. That is, the first electrode film 502, the orientation control film 503, the first piezoelectric thin film 504, the second piezoelectric thin film 505, and the second electrode film 506 are the same as the first electrode film 2, the orientation control film 506, and the first electrode film 2 of Embodiment 5, respectively. The control film 3, the first piezoelectric thin film 4, the second piezoelectric thin film 5, and the second electrode film 6 are the same.

Other points are almost the same as Embodiment 4.

Hereinafter, a method of manufacturing angular velocity sensor 400 will be described with reference to FIG. 33 . First, as shown in Figure 33(a), prepare a substrate 500 made of a silicon wafer (also refer to Figure 18) with a thickness of 0.3 mm and a diameter of 4 inches, and as shown in Figure 33(b), sputtering A first electrode film 502 made of an iridium (Ir) thin film with a thickness of 220 nm was formed on a substrate 500 by using the method. The first electrode film 502 was obtained by heating the substrate 500 to 400° C. using a sputtering apparatus, and forming a film using an iridium (Ir) target in an argon gas of 1 Pa with 200 W high-frequency power for 12 minutes.

Next, as shown in FIG. 33(c), an orientation control film 503 with a thickness of 40 nm was formed on the first electrode film 502 by sputtering. The orientation control film 503 was formed by heating the substrate 500 to a temperature of 600° C. by using a sintered target prepared by adding an excess of 12 mol % of lead oxide (PbO) to PLT containing 14 mol % of lanthanum, In a mixed environment of argon and oxygen (gas volume ratio Ar:0 ₂ =19:1), the vacuum degree is 0.8 Pa, and the film is obtained by 300W high-frequency electroforming for 12 minutes. The step of forming the alignment control film 503 includes a step of preferentially orienting the alignment control film 503 on the (111) plane.

Next, as shown in FIG. 33(d), a first piezoelectric thin film 504 is formed on the orientation control film 503 by a sputtering method, and then a second piezoelectric thin film 504 is continuously formed on the first piezoelectric thin film 504 by a sputtering method. The electric thin film 505 forms a piezoelectric laminated film. The first piezoelectric laminated film 504 is composed of a (111) preferentially oriented PZT film with a thickness of 50 nm, and the second piezoelectric film 505 is composed of a (111) oriented PZT film with a thickness of 3500 nm. The piezoelectric laminated film is formed as follows: First, a 6-inch-diameter sintered body target (composition molar ratio Pb:Zr: Ti=1.20:0.53:0.47) was used as a target, and the silicon substrate 500 on which the first electrode film 502 and the orientation control film 503 were formed on the surface was heated and kept at a temperature of 580°C in advance, and a mixed gas of argon and oxygen was used as the sputtering injecting gas, making the gas pressure 0.2Pa, making the mixing ratio argon:oxygen = 38:2, making the flow rate 40ml per minute, and making the plasma generation power 3kW, under these conditions the first piezoelectric thin film 504 was formed for 50 seconds, and then the film formation was stopped, and the mixing ratio of the sputtering gas was immediately changed to argon:oxygen=79:1. Other conditions remained unchanged, and the second piezoelectric thin film 505 was formed for 2900 seconds. The step of forming the piezoelectric multilayer film includes a step of preferentially orienting the piezoelectric multilayer film on the (111) plane through the orientation control film 503 .

Next, as shown in FIG. 33(e), a second electrode film 506 having a thickness of 200 nm was formed on the second piezoelectric thin film 505 by sputtering. The second electrode film 506 was obtained by electroforming with a high frequency wave of 200 W for 10 minutes in an argon gas of 1 Pa using a platinum (Pt) target at room temperature.

Next, as shown in FIG. 33(f), the second electrode film 506 is patterned to form drive electrodes 507, 507 and detection electrodes 508 (see also FIG. 18). That is, a photosensitive resin is coated on the second electrode film 506, and the pattern of the driving electrodes 507, 507 and the detection electrodes 508 is exposed to the photosensitive resin, and then, the photosensitive resin of the unexposed part is removed, and the removal is performed by etching. The portion of the second electrode film 506 covered with the photosensitive resin is removed, and then the photosensitive resin on the drive electrodes 507, 507 and the detection electrode 508 is removed.

Next, the first piezoelectric thin film 504, the second piezoelectric thin film 505, the orientation control film 503, and the first electrode film 502 are patterned, and at the same time, the substrate 500 is patterned to form the fixed portion 500a and the vibrating portion 500b. , 500b. Then, the substrate 500 is processed into a tuning fork shape as shown in FIG. 31 . In this way, the angular velocity sensor 400 can be obtained.

As described above, according to this embodiment, the same effect as that of Embodiment 4 can be obtained.

In addition, in the present embodiment, only one pair of vibrating portions 500b, 500b is provided on the substrate 500, but multiple pairs of vibrating portions 500b, 500b may be provided in order to detect rotations of multiple axes extending in various directions. the angular velocity.

In addition, in this embodiment, the first electrode film 502, the orientation control film 503, and the first piezoelectric body are sequentially stacked on the vibrating portion 500b of the substrate 500 and the part of the fixed portion 500a on the vibrating portion 500b side. The thin film 504, the second piezoelectric thin film 505, and the second electrode film 506 may be laminated only on each vibrating portion 500b.

(Other implementations)

In each of the above-mentioned embodiments, the piezoelectric element of the present invention is used in an inkjet head (inkjet type recording device) and an angular velocity sensor. In addition, it can also be applied to film capacitors and permanent memory elements. Charge accumulating capacitors, various actuators, infrared sensors, ultrasonic sensors, pressure sensors, acceleration sensors, flow sensors, vibration sensors, piezoelectric transformers, piezoelectric ignition elements, piezoelectric loudspeakers, piezoelectric microphones, piezoelectric Electric filters, piezoelectric pickups, tuning fork oscillators, delay lines, etc. It is especially suitable for the head supporting mechanism provided on the substrate with a head for recording or reproducing information on the rotationally driven disk in the disk device (used as a computer storage device, etc.). A thin-film piezoelectric actuator for a disk device that deforms a substrate and displaces a head (for example, refer to JP-A-2001-332041). That is, in this thin film piezoelectric element, the first electrode film, the first piezoelectric thin film, the second piezoelectric thin film, and the second electrode film are sequentially laminated as in the above-mentioned embodiments, and the second electrode film bonded to the substrate, or by sequentially laminating a first electrode film, an orientation control film, a first piezoelectric thin film, a second piezoelectric thin film, and a second electrode film, and bonding the second electrode film to the above-mentioned made of substrate.

(Industrial Utilization Possibility)

The piezoelectric element of the present invention is useful not only as an inkjet head but also as an angular velocity sensor used in a gyro element or the like. In addition, it can also be applied to micromechanical devices such as optical switch components.

Claims (52)

1. A piezoelectric element comprising: a first electrode film, a first piezoelectric thin film disposed on the first electrode film, and a second piezoelectric thin film disposed on the first piezoelectric thin film The formed piezoelectric laminated film and the second electrode film provided on the piezoelectric laminated film are characterized in that: The above-mentioned piezoelectric laminated film is composed of a perovskite-type oxide preferentially oriented on the (111) plane of a rhombohedral system or a tetragonal system; The above-mentioned first and second piezoelectric thin films are aggregates of columnar particles in continuous contact with each other; The average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is larger than the average cross-sectional diameter of the columnar particles of the first piezoelectric thin film; A ratio of the thickness of the piezoelectric laminate film to the average cross-sectional diameter of the columnar particles of the second piezoelectric thin film is not less than 20 and not more than 60. 2. The piezoelectric element according to claim 1, characterized in that: The columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of not less than 40 nm and not more than 70 nm, and a length of not less than 5 nm and not more than 100 nm. 3. The piezoelectric element according to claim 1, characterized in that: The columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of not less than 60 nm and not more than 200 nm, and a length of not less than 2500 nm and not more than 5000 nm. 4. The piezoelectric element according to claim 1, characterized in that: The first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate; The (111) crystal orientation ratio of the first piezoelectric thin film is greater than or equal to 50% and less than or equal to 80%; The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%. 5. The piezoelectric element according to claim 1, characterized in that: The chemical composition ratio of the piezoelectric laminated film is represented by Pb:Zr:Ti=(1+a):b:(1-b); b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60; The Pb content of the first piezoelectric thin film is greater than the Pb content of the second piezoelectric thin film; The a value of the first piezoelectric thin film is greater than or equal to 0.05 and less than or equal to 0.15; The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10. 6. The piezoelectric element according to claim 1, characterized in that: The above-mentioned piezoelectric laminated film is made by adding at least one of magnesium and manganese to lead zirconate titanate, and the added amount is more than 0 and less than or equal to 10 mol%. 7. The piezoelectric element according to claim 1, characterized in that: The first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm or more and 30 nm or less. 8. The piezoelectric element according to claim 1, characterized in that: Also includes: an orientation control film provided between the first electrode film and the first piezoelectric thin film; The above-mentioned orientation control film is composed of a perovskite-type oxide that is preferentially oriented to the (111) plane of the cubic system or the tetragonal system. 9. The piezoelectric element according to claim 8, characterized in that: The columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of not less than 40 nm and not more than 70 nm, and a length of not less than 5 nm and not more than 100 nm. 10. The piezoelectric element according to claim 8, characterized in that: The columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of not less than 60 nm and not more than 200 nm, and a length of not less than 2500 nm and not more than 5000 nm. 11. The piezoelectric element according to claim 8, characterized in that: The first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate; The (111) crystal orientation ratio of the first piezoelectric thin film is greater than or equal to 50% and less than or equal to 80%; The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%. 12. The piezoelectric element according to claim 8, characterized in that: The chemical composition ratio of the piezoelectric laminated film is represented by Pb:Zr:Ti=(1+a):b:(1-b); b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60; The Pb content of the first piezoelectric thin film is greater than the Pb content of the second piezoelectric thin film; The a value of the first piezoelectric thin film is greater than or equal to 0.05 and less than or equal to 0.15; The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10. 13. The piezoelectric element according to claim 8, characterized in that: The orientation control film is composed of an oxide mainly composed of perovskite-type lead lanthanum zirconate titanate; The (111) crystal orientation ratio of the above-mentioned orientation control film is equal to or greater than 50%. 14. The piezoelectric element according to claim 8, characterized in that: The chemical composition ratio of the above-mentioned orientation control film is represented by Pb:La:Zr:Ti=x×(1-z):z:y:(1-y); The above x value is greater than or equal to 1.0 and less than or equal to 1.20; The above y value is greater than or equal to 0 and less than or equal to 0.20; The above-mentioned z value is more than 0 and less than or equal to 0.30. 15. The piezoelectric element according to claim 8, characterized in that: The orientation control film is made by adding at least one of magnesium and manganese to lead lanthanum zirconate titanate, and the added amount is more than 0 and less than or equal to 10 mol%. 16. The piezoelectric element according to claim 8, characterized in that: The piezoelectric laminate film is formed by adding at least one of magnesium and manganese to lead zirconate titanate in an amount of more than 0 and less than or equal to 10 mol%. 17. The piezoelectric element according to claim 8, characterized in that: The first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm or more and 30 nm or less. 18. An inkjet head comprising: a piezoelectric element in which a first electrode film, a piezoelectric laminated film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated, and The vibration layer on the surface of the piezoelectric element on the side of the second electrode film, and the pressure chamber bonded to the surface of the vibration layer opposite to the second electrode film and forming a pressure chamber for accommodating ink. A component that displaces the vibrating layer in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film to discharge the ink in the pressure chamber, characterized in that: The piezoelectric element is the piezoelectric element according to claim 1 . 19. An inkjet head comprising: a piezoelectric element in which a first electrode film, a piezoelectric laminated film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated, and The vibration layer on the surface of the piezoelectric element on the side of the first electrode film, and the pressure chamber bonded to the surface of the vibration layer opposite to the first electrode film and forming a pressure chamber for accommodating ink. A component that displaces the vibrating layer in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film to discharge the ink in the pressure chamber, characterized in that: The piezoelectric element is the piezoelectric element according to claim 1 . 20. An inkjet recording device, characterized in that: comprising: the inkjet head of claim 18, and A relative movement mechanism that allows the above-mentioned inkjet head and the recording medium to move relatively; When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording. 21. An inkjet recording device, characterized in that: comprising: the inkjet head of claim 19, and A relative movement mechanism that allows the above-mentioned inkjet head and the recording medium to move relatively; When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording. 22. An angular velocity sensor comprising a substrate having a fixed portion and at least a pair of vibrating portions extending from the fixed portion in a direction extending from the fixed portion toward the center axis of rotation of the detected angular velocity, and at least each vibrating portion of the substrate is provided with A piezoelectric element in which a first electrode film, a piezoelectric laminated film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated, and the second electrode film on each vibrating portion is covered with a Patterned as at least one driving electrode for vibrating the vibrating portion in its width direction and at least one detecting electrode for detecting deformation in the thickness direction of the vibrating portion, characterized in that: The piezoelectric element is the piezoelectric element according to claim 1 . 23. The angular velocity sensor according to claim 22, characterized in that: The columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of not less than 40 nm and not more than 70 nm, and a length of not less than 5 nm and not more than 100 nm. 24. The angular velocity sensor according to claim 22, characterized in that: The columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of not less than 60 nm and not more than 200 nm, and a length of not less than 2500 nm and not more than 5000 nm. 25. The angular velocity sensor according to claim 22, characterized in that: The first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate; The (111) crystal orientation ratio of the first piezoelectric thin film is greater than or equal to 50% and less than or equal to 80%; The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%. 26. The angular velocity sensor according to claim 22, characterized in that: The chemical composition ratio of the piezoelectric laminated film is represented by Pb:Zr:Ti=(1+a):b:(1-b); b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60; The Pb content of the first piezoelectric thin film is greater than the Pb content of the second piezoelectric thin film; The a value of the first piezoelectric thin film is greater than or equal to 0.05 and less than or equal to 0.15; The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10. 27. The angular velocity sensor according to claim 22, characterized in that: The above-mentioned piezoelectric laminated film is made by adding at least one of magnesium and manganese to lead zirconate titanate, and the added amount is more than 0 and less than or equal to 10 mol%. 28. The angular velocity sensor according to claim 22, characterized in that: The first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm or more and 30 nm or less. 29. The angular velocity sensor according to claim 22, characterized in that: The aforementioned substrate is made of silicon. 30. A method of manufacturing a piezoelectric element, characterized in that: Including: the process of forming the first electrode film on the substrate by sputtering, A step of forming first and second piezoelectric thin films made of rhombohedral or tetragonal perovskite oxides on the first electrode film by sputtering to form a piezoelectric laminated film, and A step of forming a second electrode film on the piezoelectric laminate film; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed to be preferentially oriented to the (111) plane. 31. A method of manufacturing an inkjet head, characterized in that: Including: the process of forming the first electrode film on the substrate by sputtering, A step of forming first and second piezoelectric thin films made of rhombohedral or tetragonal perovskite oxides on the first electrode film by sputtering to form a piezoelectric laminated film, A step of forming a second electrode film on the above-mentioned piezoelectric laminated film, A step of forming a vibration layer on the second electrode film, a step of bonding a pressure chamber member for forming a pressure chamber to the surface of the vibrating layer opposite to the second electrode film, and A step of removing the substrate after the bonding step; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed to be preferentially oriented to the (111) plane. 32. A method of manufacturing an inkjet head, characterized in that: including: a step of forming a vibration layer on a pressure chamber substrate forming a pressure chamber, a step of forming a first electrode film on the vibration layer by a sputtering method, A step of forming first and second piezoelectric thin films made of rhombohedral or tetragonal perovskite oxides on the first electrode film by sputtering to form a piezoelectric laminated film, A step of forming a second electrode film on the above-mentioned piezoelectric laminated film, and A process of forming a pressure chamber on the pressure chamber substrate; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed to be preferentially oriented to the (111) plane. 33. A method of manufacturing an angular velocity sensor, characterized in that: Including: the process of forming the first electrode film on the substrate by sputtering, A step of forming first and second piezoelectric thin films made of rhombohedral or tetragonal perovskite oxides on the first electrode film by sputtering to form a piezoelectric laminated film, A step of forming a second electrode film on the above-mentioned piezoelectric laminated film, a step of patterning the second electrode film to form a drive electrode and a detection electrode, a step of patterning the piezoelectric laminate film and the first electrode film, and A step of patterning the substrate to form a fixed part and a vibrating part; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed to be preferentially oriented to the (111) plane. 34. An inkjet head comprising: a piezoelectric film formed by sequentially laminating a first electrode film, an orientation control film, a piezoelectric laminate film composed of first and second piezoelectric thin films, and a second electrode film. A body element, a vibrating layer provided on the surface of the piezoelectric body element on the side of the second electrode film, and a vibrating layer bonded to the surface of the vibrating layer opposite to the side of the second electrode film and formed to hold ink. A pressure chamber part of the pressure chamber; the vibration layer is displaced in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film, and the ink in the pressure chamber is ejected, characterized in that: The piezoelectric element is the piezoelectric element according to claim 8 . 35. An inkjet head comprising: a piezoelectric film formed by sequentially laminating a first electrode film, an orientation control film, a piezoelectric laminate film composed of first and second piezoelectric thin films, and a second electrode film. A body element, a vibrating layer provided on the surface of the piezoelectric body element on the side of the first electrode film, and a vibrating layer bonded to the surface of the vibrating layer opposite to the first electrode film and formed to hold ink. A pressure chamber part of the pressure chamber; the vibration layer is displaced in the layer thickness direction by the piezoelectric effect of the piezoelectric laminated film, and the ink in the pressure chamber is ejected, characterized in that: The piezoelectric element is the piezoelectric element according to claim 8 . 36. An inkjet recording device, characterized in that: comprising: the inkjet head of claim 34, and A relative movement mechanism that allows the above-mentioned inkjet head and the recording medium to move relatively; When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording. 37. An inkjet recording device, characterized in that: comprising: the inkjet head of claim 35, and A relative movement mechanism that allows the above-mentioned inkjet head and the recording medium to move relatively; When the inkjet head and the recording medium are relatively moved by the relative movement mechanism, the ink in the pressure chamber is ejected from the nozzle hole communicating with the pressure chamber to the recording medium to perform recording. 38. An angular velocity sensor comprising a substrate having a fixed portion and at least a pair of vibrating portions extending from the fixed portion in a direction extending from the fixed portion toward the center axis of rotation of the detected angular velocity, and at least each vibrating portion of the substrate is provided with In a piezoelectric element in which a first electrode film, an orientation control film, a piezoelectric laminated film composed of first and second piezoelectric thin films, and a second electrode film are sequentially laminated, the The second electrode film is patterned into at least one driving electrode for vibrating the vibrating portion in its width direction and at least one detecting electrode for detecting deformation in the thickness direction of the vibrating portion, characterized in that: The piezoelectric element is the piezoelectric element according to claim 8 . 39. The angular velocity sensor according to claim 38, characterized in that: The columnar particles of the first piezoelectric thin film have an average cross-sectional diameter of not less than 40 nm and not more than 70 nm, and a length of not less than 5 nm and not more than 100 nm. 40. The angular velocity sensor according to claim 38, characterized in that: The columnar particles of the second piezoelectric thin film have an average cross-sectional diameter of not less than 60 nm and not more than 200 nm, and a length of not less than 2500 nm and not more than 5000 nm. 41. The angular velocity sensor according to claim 38, characterized in that: The first and second piezoelectric thin films are composed of an oxide mainly composed of perovskite-type lead zirconate titanate; The (111) crystal orientation ratio of the first piezoelectric thin film is greater than or equal to 50% and less than or equal to 80%; The (111) crystal orientation ratio of the second piezoelectric thin film is not less than 95% and not more than 100%. 42. The angular velocity sensor according to claim 38, characterized in that: The chemical composition ratio of the piezoelectric laminated film is represented by Pb:Zr:Ti=(1+a):b:(1-b); b values of the first and second piezoelectric thin films are the same value of not less than 0.40 and not more than 0.60; The Pb content of the first piezoelectric thin film is greater than the Pb content of the second piezoelectric thin film; The a value of the first piezoelectric thin film is greater than or equal to 0.05 and less than or equal to 0.15; The value a of the second piezoelectric thin film is equal to or greater than 0 and equal to or less than 0.10. 43. The angular velocity sensor according to claim 38, characterized in that: The orientation control film is composed of an oxide mainly composed of perovskite-type lead lanthanum zirconate titanate; The (111) crystal orientation ratio of the above-mentioned orientation control film is equal to or greater than 50%. 44. The angular velocity sensor according to claim 38, characterized in that: The chemical composition ratio of the above-mentioned orientation control film is represented by Pb:La:Zr:Ti=x×(1-z):z:y:(1-y); The above x value is greater than or equal to 1.0 and less than or equal to 1.20; The above y value is greater than or equal to 0 and less than or equal to 0.20; The above-mentioned z value is more than 0 and less than or equal to 0.30. 45. The angular velocity sensor according to claim 38, characterized in that: The orientation control film is made by adding at least one of magnesium and manganese to lead lanthanum zirconate titanate, and the added amount is more than 0 and less than or equal to 10 mol%. 46. The angular velocity sensor according to claim 38, characterized in that: The piezoelectric laminate film is formed by adding at least one of magnesium and manganese to lead zirconate titanate in an amount of more than 0 and less than or equal to 10 mol%. 47. The angular velocity sensor according to claim 38, characterized in that: The first electrode film is composed of a noble metal composed of platinum, iridium, palladium, or ruthenium, or an alloy containing the noble metal, and is an aggregate of columnar particles with an average cross-sectional diameter of 20 nm or more and 30 nm or less. 48. The angular velocity sensor according to claim 38, characterized in that: The above substrate is made of silicon. 49. A method of manufacturing a piezoelectric element, characterized in that: Including: the process of forming the first electrode film on the substrate by sputtering, A step of forming an orientation control film made of a cubic or tetragonal perovskite oxide on the first electrode film by sputtering, A step of forming first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides on the above-mentioned orientation control film by sputtering to form a piezoelectric laminated film, and A step of forming a second electrode film on the piezoelectric laminate film; In the step of forming the above-mentioned orientation control film, the orientation control film is formed to be preferentially oriented to the (111) plane; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed so as to be preferentially oriented to the (111) plane via the orientation control film. 50. A method of manufacturing an inkjet head, characterized in that: Including: the process of forming the first electrode film on the substrate by sputtering, A step of forming an orientation control film made of a cubic or tetragonal perovskite oxide on the first electrode film by sputtering, A step of forming first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides on the above-mentioned orientation control film by sputtering to form a piezoelectric laminated film, A step of forming a second electrode film on the above-mentioned piezoelectric laminated film, A step of forming a vibration layer on the second electrode film, a step of bonding a pressure chamber member for forming a pressure chamber to a surface of the vibrating layer opposite to the second electrode film, and A step of removing the substrate after the bonding step; In the step of forming the above-mentioned orientation control film, the orientation control film is formed to be preferentially oriented to the (111) plane; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed so as to be preferentially oriented to the (111) plane via the orientation control film. 51. A method of manufacturing an inkjet head, characterized in that: including: a step of forming a vibration layer on a pressure chamber substrate forming a pressure chamber, a step of forming a first electrode film on the vibration layer by a sputtering method, A step of forming an orientation control film made of a cubic or tetragonal perovskite oxide on the first electrode film by sputtering, A step of forming first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides on the above-mentioned orientation control film by sputtering to form a piezoelectric laminated film, A step of forming a second electrode film on the above-mentioned piezoelectric laminated film, and A process of forming a pressure chamber on the pressure chamber substrate; In the step of forming the above-mentioned orientation control film, the orientation control film is formed to be preferentially oriented to the (111) plane; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed so as to be preferentially oriented to the (111) plane via the orientation control film. 52. A method of manufacturing an angular velocity sensor, characterized in that: Including: the process of forming a first electrode film on a substrate by a sputtering method, A step of forming an orientation control film made of a cubic or tetragonal perovskite oxide on the first electrode film by sputtering, A step of forming first and second piezoelectric thin films composed of rhombohedral or tetragonal perovskite oxides on the above-mentioned orientation control film by sputtering to form a piezoelectric laminated film, The step of forming a second electrode film on the above-mentioned piezoelectric laminated film, a step of patterning the second electrode film to form a drive electrode and a detection electrode, a step of patterning the piezoelectric laminate film, the orientation control film, and the first electrode film, and A step of patterning the substrate to form a fixed part and a vibrating part; In the step of forming the above-mentioned orientation control film, the orientation control film is formed to be preferentially oriented to the (111) plane; In the step of forming the piezoelectric multilayer film, the piezoelectric multilayer film is formed so as to be preferentially oriented to the (111) plane via the orientation control film.

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