JP2008100887A - Raw material powder for film deposition, film structure, method for producing them and piezoelectric element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To promote grain growth and improvement of characteristics upon annealing in a film deposited by an AD (Aerosol Deposition) process, in the production of raw material powder for film deposition used for film deposition by an AD process, by uniformly sticking a grain growth auxiliary to the surface of each base material grain. <P>SOLUTION: In the method for producing raw material powder for film deposition, raw material powder is sprayed toward a substrate, so as to produce raw material used for depositing a film having the composition of the raw material powder. The method comprises: a stage (a) where, using the nitrate or sulfate of a prescribed element, a grain growth auxiliary having a prescribed composition is stuck to the surface of each base material grain including a lead-based piezoelectric material; and a stage (b) where energy is applied to the grain growth auxiliary stuck to the surface of each base material grain, thus the remaining nitrate or sulfate or nitrate ions or sulfate ions which have been comprised therein are decomposed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a raw material powder used in an aerosol deposition (AD) method in which a raw material is deposited on a substrate by spraying an aerosol in which the raw material powder is dispersed toward the substrate. The present invention relates to a film structure manufactured using the same and a manufacturing method thereof. Furthermore, the present invention relates to a piezoelectric element manufactured using such raw material powder.

  In recent years, in the field of micro electrical mechanical systems (MEMS), electrons that exhibit a predetermined function by applying voltage, such as dielectrics, piezoelectrics, magnetics, pyroelectrics, and semiconductors. Research for manufacturing elements including functional materials such as ceramics by using a film forming technique is actively underway.

  In general, an aerosol deposition method (hereinafter also referred to as “AD method”) is known as a method for forming a film of a brittle material on the surface of a substrate. The AD method is a film forming method in which a raw material is deposited on a substrate by spraying an aerosol generated by dispersing fine powder of the raw material in a gas toward the substrate. Here, the aerosol refers to solid or liquid fine particles suspended in a gas. The AD method is also called a jet deposition method or a gas deposition method.

  In the AD method, the raw material powder for film formation sprayed at a high speed collides with the substrate and the lower layer such as the previously formed deposit, and the crushing surface generated by crushing the powder at the time of the collision. Is formed by a mechanochemical reaction that adheres to the lower layer. By using such an AD method, a dense and strong thick film that does not contain impurities can be formed. Therefore, for example, it is expected that the performance of these devices can be improved by forming a piezoelectric film used for piezoelectric elements such as piezoelectric actuators, piezoelectric pumps, inkjet printer heads, ultrasonic transducers, etc. by the AD method. Yes.

  In recent years, the film forming raw material powder used in the AD method has been improved, and it is considered that several problems in the AD method can be solved. As one of those problems, the raw material powder for film formation contained in the aerosol aggregates and adheres to the inner walls of the nozzles and pipes constituting the film formation apparatus, and as a result, on the substrate. There is a problem that unevenness occurs in the thickness of the film. In order to solve this problem, it has been considered to improve the fluidity of the film forming raw material powder by devising the composition material of the film forming raw material powder. Furthermore, since the improvement of the raw material powder for film formation is greatly related to improving the characteristics of the structure formed on the substrate, there are various methods for manufacturing the raw material powder for film formation used in the AD method. Technology has been developed.

  As related technologies, in Patent Document 1 and Patent Document 2 below, composite fine particles are formed through a process of coating one or more types of ductile materials on the surface of brittle material fine particles, and then the composite fine particles are rapidly applied to the substrate surface. Describes a method of creating a composite structure to be collided with. According to this composite structure creation method, it is described that a composite structure having a low relative dielectric constant and a dense structure can be generated. However, Patent Document 1 and Patent Document 2 only describe that a ductile material powder and a brittle material powder are mixed to form a film by an AD method as a specific example. There is no description of the effect of uniformly dispersing the ductile material coated on the surface of the fine particles.

  Patent Document 3 and Patent Document 4 below describe a composite structure in which a composite fine particle is formed through a step of coating a brittle material fine particle surface with another brittle material, and then the composite fine particle collides with the substrate surface at high speed. It describes how to make things. However, also in Patent Document 3 and Patent Document 4, as a specific example, only the film formed by the AD method by mixing the powder of the brittle material and the powder of another brittle material is described, There is no description on the effect of uniformly dispersing another brittle material coated on the surface of the brittle material fine particles.

Further, in Patent Document 5 below, in order to suppress the condensation of the raw material powder in the generation of the aerosol, the first particle as a base material and a particle size smaller than the first particle, A step (a) of preparing a film forming raw material powder containing second particles fixed so as to cover the surface of one particle, and the film forming raw material powder prepared in step (a) on the substrate A film forming method including a step (b) of depositing a composition material of film forming raw material powder on a substrate by spraying toward the substrate. However, Patent Document 5 does not describe a measure for preventing the segregation of the composition material of the second particles in the formed film and improving the characteristics.
JP2003-277948A (7th, 10th page, FIG. 4) International Publication 2002/36855 (5th page, FIG. 4) JP2003-277949A (page 8, page 10, FIG. 4) International Publication 2002/34966 (5th page, FIG. 4) Japanese Patent Laying-Open No. 2005-344171 (5th and 7th pages, FIG. 3)

  Therefore, in view of the above points, the present invention provides a method for producing a raw material powder for film formation used in film formation by the AD method. The object is to promote grain growth and property improvement during annealing of the formed film.

In order to solve the above-mentioned problems, a film forming raw material powder manufacturing method according to one aspect of the present invention is used to form a film having a raw material powder composition by spraying the raw material powder onto a substrate. A method for producing raw material powder, selected from lead (Pb), zinc (Zn), cerium (Ce), copper (Cu), ytterbium (Yb), dysprosium (Dy), and nickel (Ni) Using at least one elemental nitrate or sulfate of lead, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), A grain growth aid containing at least one composition selected from dysprosium oxide (Dy ₂ O ₃ ) and nickel oxide (NiO) is fixed to the surface of the base material particle containing the lead-based piezoelectric material. And (b) a step of decomposing remaining nitrates or sulfates or nitrate ions or sulfate ions contained therein by applying energy to the grain growth aid fixed to the surface of the base material particles (b) ).

A manufacturing method of a film structure according to one aspect of the present invention is a manufacturing method of a film structure in which a film having a composition of raw material powder is formed by spraying the raw material powder toward a substrate. ), Zinc (Zn), cerium (Ce), copper (Cu), ytterbium (Yb), dysprosium (Dy), and at least one element nitrate or sulfate selected from nickel (Ni) Used, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and nickel oxide A step (a) of fixing a grain growth aid containing at least one composition selected from among (NiO) to the surface of the base material particle containing the lead-based piezoelectric material; and a grain fixed to the surface of the base material particle Step (b) for decomposing remaining nitrates or sulfates or nitrate ions or sulfate ions contained therein by applying energy to the growth aid, and the raw material powder obtained in step (b) in an aerosol state The step (c) of forming a film having the composition of the raw material powder directly or indirectly on the substrate by spraying it toward the substrate, and the film structure is subjected to a heat treatment to produce crystals in the film. And (d) growing a grain.

The film forming raw material powder according to one aspect of the present invention is a raw material powder used for forming a film having a composition of raw material powder by spraying the raw material powder toward the substrate, and is a lead-based powder. Base material particles containing a piezoelectric material, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃₎ And a grain growth aid comprising at least one composition selected from nickel oxide (NiO) and fixed so as to cover the surface of the base material particles.

A film structure according to one aspect of the present invention is a film structure manufactured by forming a film having a composition of a raw material powder by spraying the raw material powder toward the substrate, and (a) a substrate And (b) a film formed directly or indirectly on the substrate, including a lead-based piezoelectric material and having an average grain size of 10 nm to 500 nm, lead oxide (PbO), zinc oxide ( ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and at least one selected from nickel oxide (NiO) And a film containing a grain growth aid containing the composition.

Furthermore, a piezoelectric element according to one aspect of the present invention is a piezoelectric element manufactured by forming a film having a composition of raw material powder by spraying the raw material powder toward a substrate, and (a) first 1, (b) a piezoelectric film formed on the first electrode, comprising crystal grains containing a lead-based piezoelectric material, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO) ₂ ), a grain growth aid comprising at least one composition selected from copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and nickel oxide (NiO) And (c) a second electrode formed on the piezoelectric film.

  According to the present invention, energy is applied to the grain growth aid fixed to the surface of the base material particle, and the grain growth aid is uniformly fixed to the surface of the base material particle, thereby forming a film formed by the AD method. It is possible to promote grain growth and property improvement during annealing.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, the same reference number is attached | subjected to the same component and description is abbreviate | omitted.
FIG. 1 is a flowchart showing a method for manufacturing a membrane structure according to an embodiment of the present invention.
First, the production of film forming raw material powder will be described. In step S1, a powder of lead-based piezoelectric material (specifically, PNN-PZT manufactured by Furuuchi Chemical Co., Ltd.), which is a material of the base material particles, is dispersed in a solvent such as IPA (isopropyl alcohol).

  Further, in step S2, a desired sintering aid raw material is dissolved in a solvent to prepare a solution. The raw material for the sintering aid is selected from lead (Pb), zinc (Zn), cerium (Ce), copper (Cu), ytterbium (Yb), dysprosium (Dy), and nickel (Ni). In addition, at least one elemental nitrate or sulfate is used. In order to prevent the powder from agglomerating, a surfactant may be added as a dispersant.

In step S3, the solution is attached to the base material particles while evaporating the solvent in the solution using a rotary evaporator. In this process, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and oxidation Fine powder particles of nickel (NiO) are fixedly coated on the base material particles as a component of the sintering aid. However, nitrates or sulfates, or some of the nitrate ions (NO ₃ ⁺ ) or sulfate ions (SO ₄ ²⁺ ) contained in them also remain in the sintering aid.

Therefore, in this embodiment, in step S4, the film forming raw material powder is subjected to heat treatment (annealing treatment) at a predetermined temperature. In this heat treatment, energy is applied to the raw material powder for film formation to decompose nitrates or sulfates that cause pores or film cracking, or nitrate ions or sulfate ions contained therein, and SO _2. , by discharging a gas, such as NO _2, it is intended to the film-forming raw material powder and stable precursors.

  The heat treatment temperature is determined by measuring the weight change of the raw material powder for film formation in the heat treatment using a differential thermogravimetric measuring device (TG / DTA) used for observing the weight change with respect to the temperature. In the present embodiment, the annealing temperature is 550 ° C. to 650 ° C., more preferably based on the temperature at which nitrate or sulfate, which is a raw material of the sintering aid, or nitrate ions or sulfate ions contained therein is decomposed. Is determined at 600 ° C.

  In step S4, instead of heat-treating the film forming raw material powder, energy may be applied by irradiating the film forming raw material powder with electromagnetic waves. In the present application, in order to stabilize and homogenize the sintering aid, various processes for applying energy to the raw material powder for film formation that is a composite fine particle are also referred to as “stabilization process”.

Further, in step S3, the following method may be used in place of the embodiment in which the base material particles are coated with the sintering aid using a rotary evaporator. Also by these methods, the same effects as those in the example can be confirmed.
As a first method, the sintering aid can be coated onto the base material particles by spraying the liquefied sintering aid onto the base material particles using a fluid spray drying method.

  As a second method, the sintering aid can be coated on the base material particles by vaporizing the sintering aid and attaching it to the base material particles. For example, it is possible to vaporize the sintering aid by heating it using a batch rotary kiln or rotary tube furnace manufactured by Hiroki Co., Ltd., and coat it on the base material particles. Alternatively, using a laser ablation system manufactured by Nara Machinery Co., Ltd., the sintering aid can be vaporized by irradiating it with a laser beam and coated on the base material particles.

  Next, the film forming process will be described. Using the film forming raw material powder thus manufactured, film formation by the AD method is performed in step S5. The average particle size of the raw material powder for film formation is preferably from 0.1 μm to 10 μm, more preferably from 0.3 μm to 1 μm, which is a particle size suitable for forming a dense film by the AD method. . The film forming raw material powder is crushed by colliding with the substrate, and the average particle diameter of the AD film formed thereby is 10 nm or more and 500 nm or less.

  Thereafter, in step S6, the AD film is annealed (heat treatment) in an air atmosphere at 800 ° C. As a result, crystal grains in the AD film grow and the grain size increases. In the present embodiment, a liquid phase is formed at the grain boundary in the annealing process by using the film forming raw material powder produced by coating the base material particles with the sintering aid subjected to the stabilization process, Crystal growth can be promoted by lowering the annealing temperature.

  FIG. 2 is a schematic diagram showing the configuration of a film forming apparatus used in the method for manufacturing a film structure according to one embodiment of the present invention. As shown in FIG. 2, this film forming apparatus includes aerosol generating units 1 to 4 that generate aerosols, film forming units 6 to 9, an aerosol transport pipe 5 that connects the two, and operations of the respective units. The control part 10 which controls is included.

  The aerosol generation unit includes an aerosol generation chamber 1, a vibration table 2, a hoisting gas nozzle 3, and a pressure adjusting gas nozzle 4. The aerosol generation chamber 1 is a container in which the raw material powder 11 for film formation is disposed, and here, aerosol generation is performed. The aerosol generation chamber 1 is installed on a vibration table 2 that vibrates at a predetermined frequency in order to efficiently generate aerosol by stirring the film forming raw material powder 11.

  The winding gas nozzle 3 generates a cyclone flow by introducing a carrier gas supplied from an external gas cylinder into the aerosol generation chamber 1. Thereby, the film-forming raw material powder 11 disposed in the aerosol generation chamber 1 is rolled up and dispersed to generate an aerosol.

  The pressure adjusting gas nozzle 4 adjusts the gas pressure in the aerosol generating chamber 1 by introducing a carrier gas supplied from an external gas cylinder into the aerosol generating chamber 1. Thereby, the difference between the pressure in the aerosol generation chamber 1 and the pressure in the film formation chamber 6 is adjusted.

The flow rate of the gas introduced by the winding gas nozzle 3 and the pressure adjusting gas nozzle 4 is adjusted by the flow rate adjusting units 3a and 4a. The carrier gas supplied by the hoisting gas nozzle 3 and the pressure adjusting gas nozzle 4 is He (helium), O ₂ (oxygen), N ₂ (nitrogen), Ar (argon), or a mixed gas thereof, or Dry air or the like is used. In addition, in the aerosol production | generation part shown in FIG. 2, the powder feeder generally known as a powder supply apparatus may be used.

  The aerosol transport pipe 5 is a path for transporting the aerosol from the aerosol generating unit toward the film forming unit. In the film forming chamber 6, the aerosol transport pipe 5 is connected to a nozzle 7 for injecting aerosol.

  The film forming unit includes a film forming chamber 6, an injection nozzle 7, a substrate stage 8, and an exhaust pipe 9. The inside of the film forming chamber 6 is evacuated by an evacuation pump connected to an evacuation pipe 9, thereby maintaining a predetermined degree of vacuum. The injection nozzle 7 has an opening of a predetermined shape and size, and injects the aerosol of the film forming raw material powder supplied from the aerosol generation chamber 1 through the aerosol transport pipe 5 toward the substrate 12. . The velocity of the aerosol ejected from the ejection nozzle 7 is determined by the pressure difference between the aerosol generation chamber 1 and the film formation chamber 6.

  The substrate stage 8 on which the substrate 12 is fixed is a three-dimensionally movable stage for controlling the relative position and relative speed between the spray nozzle 7 and the substrate 12. By adjusting this relative speed, the thickness of the film formed per reciprocation is controlled. The substrate stage 8 may be equipped with a heater for keeping the substrate 12 at a predetermined temperature. In this embodiment, the relative position between the nozzle 7 and the substrate stage 8 is changed by moving the substrate stage 8 side. However, the position of the substrate 12 is fixed and the nozzle 7 side is moved. Anyway.

Next, the basic operation of the film forming apparatus shown in FIG. 2 will be described.
In the AD method, ceramic powder such as PZT (lead zirconate titanate) or Al ₂ O ₃ (alumina) is used as the raw material powder for film formation. As shown in FIG. 2, such film forming raw material powder 11 is disposed in the aerosol generation chamber 1, and the substrate 12 is disposed on the substrate stage 8.

  When the film forming apparatus is driven, the aerosol generated in the aerosol generating chamber 1 is introduced into the film forming chamber 6 through the aerosol transport pipe 5, sprayed from the nozzle 7, and sprayed onto the substrate 12. The film forming raw material powder 11 in the aerosol is deposited on the substrate 12 by colliding with the substrate 12 and causing a mechanochemical reaction. At that time, by moving the substrate stage 8 at a predetermined speed under the control of the control unit 10, the substrate 12 is scanned by the nozzle 7 and at a rate according to the relative speed between the nozzle 7 and the substrate 12. A film 13 having the same composition as the film forming raw material powder 11 is formed.

In the present embodiment, oxygen gas is used as the carrier gas, and the gas flow rate is adjusted to 6 liters per minute by the flow rate adjusting units 3a and 4a. Further, as the substrate 12, a substrate in which an electrode is formed by depositing 50 nm of titanium oxide (TiO ₂ ) and 500 nm of platinum (Pt) on a YSZ (yttria stabilized zirconia) substrate by a sputtering method is used. It is done. A film 13 is formed on such a substrate 12 at room temperature using the film forming apparatus already described. In this case, the AD film is indirectly formed on the YSZ substrate via the electrode, but the AD film may be directly formed on the YSZ substrate. Alternatively, a laminated structure may be formed by repeatedly forming a plurality of electrodes and an AD film.

Here, the raw material powder for film formation according to an embodiment of the present invention will be described.
The raw material powder for film formation according to the present embodiment is coated with a brittle material or a ductile material sintering aid (grain growth aid) around the brittle material particles (base material particles). Composite particles. Sintering aid (grain growth aid) is the growth of crystal grains by lowering the annealing temperature by forming a liquid phase at the grain boundary when annealing the film (AD film) formed by the AD method. It is a material for promoting the heat resistance and has a low melting point.

A lead-based piezoelectric material is used as the material of the base material particles. For example, PZT (lead zirconate titanate) or ternary lead zirconate titanate (PNN-PZT) represented by the general formula Pb (Ni, Nb) O ₃ —PbZrO ₃ —PbTiO ₃ can be used. More preferably, with respect to the composition of this PNN-PZT, (i) lead (Pb) in excess of the stoichiometric ratio, (ii) zinc (Zn), (iii) cerium (Ce), ytterbium ( Yb), dysprosium (Dy), and at least one rare earth element selected from nickel (Ni) are used. Here, it is desirable that the molar ratio of Ni in the Pb (Ni, Nb) O ₃ component is 1/3 and the molar ratio of Nb is 2/3. The addition of (i) to (iii) promotes grain growth when the formed AD film is annealed, and the piezoelectric characteristics are improved by low-temperature annealing at 700 ° C. to 900 ° C.

Examples of materials for the sintering aid include lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), and dysprosium oxide (Dy ₂ ). O ₃ ) and at least one composition selected from nickel oxide (NiO) is used. By uniformly coating the surface of the base material particles with the sintering aid, grain growth is further promoted when the formed AD film is annealed.

  FIG. 3 is a view showing SEM (scanning electron microscope) photographs of the AD films of the examples, and FIGS. 4 and 5 are views showing SEM photographs of the AD films of Comparative Examples 1 and 2, respectively. Each of them is an AD film after annealing at 800 ° C., but in the AD film shown in FIG. 4, the raw material powder for film formation is not stabilized, and the AD film shown in FIG. In the film, no sintering aid is added to the raw material powder for film formation.

  As shown in FIG. 3, when the film forming raw material powder subjected to the stabilization treatment is used, the particles in the AD film grow and the AD film is in a good state with no pores. I understand that there is. On the other hand, as shown in FIG. 4, when the film forming raw material powder not subjected to stabilization treatment is used, particles are partially grown, but columnar crystal components appear in the AD film and pores appear. Furthermore, according to the SEM-EDX analyzer, precipitation of a sintering aid component such as ZnO is detected.

  Further, as shown in FIG. 5, when the film forming raw material powder to which the sintering aid is not added is used, a dense AD film is realized without generating pores. It can be seen that is not progressing. Generally, if the growth of crystal grains does not progress, the electrical characteristics of the film structure will not be good, and it will be difficult to apply to industrial products such as piezoelectric elements.

FIG. 6 is a diagram showing hysteresis characteristics of the polarization value P for the AD film shown in FIG. FIG. 7 is a diagram showing hysteresis characteristics of the polarization value P for the AD film shown in FIG. As shown in FIG. 6, the remanent polarization value of the AD film generated using the film forming raw material powder to which the sintering aid is added is 32 μC / cm ² . On the other hand, as shown in FIG. 7, the remanent polarization value of the AD film produced using the film forming raw material powder to which no sintering aid is added is 14 μC / cm ² , which is lower than that shown in FIG. I understand that. Thus, the electrical characteristics shown in FIGS. 6 and 7 reflect the difference in the progress of crystal grain growth depending on the presence or absence of the sintering aid.

  FIG. 8 is a diagram comparing the electrical characteristics of the AD films shown in FIGS. As shown in FIG. 8, the piezoelectric characteristics d31, the relative dielectric constant, and the remanent polarization value are increased by adding a sintering aid to the film forming raw material powder and further performing a stabilization treatment. I understand. On the other hand, when the sintering aid is not added and the stabilization treatment is not performed, a large amount of pores are generated as shown in FIG. 4, and the electrical characteristics cannot be measured. However, it can be seen that the electrical characteristics are dramatically improved by performing the stabilization treatment.

  FIG. 9 is a view showing an SEM photograph of the bulk ceramic. This bulk ceramic is manufactured by press molding using the film forming raw material powder according to the present embodiment and sintering at 800 ° C. However, as shown in FIG. 9, since sintering did not proceed sufficiently, pores were generated so much that electrical characteristics could not be measured.

  FIG. 10 is a diagram comparing the densities of the bulk ceramic shown in FIG. 9 and the two types of AD films shown in FIGS. 3 and 5 respectively. In general, relative density is used as a parameter for comparing the density of particles in a structure. As shown in FIG. 10, the bulk ceramic has the lowest relative density. This is because when the film is formed by the AD method, the particles are crushed by collision and the average particle size is reduced to about several tens of nm, so that a dense film can be formed. Further, since the free energy increases by increasing the surface area relative to the volume of the particles, it is considered that the growth of crystal grains can be greatly promoted even by adding a small amount of a sintering aid. Therefore, it can be said that the film forming raw material powder according to the present embodiment has a great effect when the film is formed by the AD method. Further, although the density and relative density of the AD film shown in FIG. 3 are slightly lower than those of the AD film shown in FIG. 5, it can be said that it is practically equivalent.

Next, a piezoelectric element manufactured using the film forming raw material powder according to an embodiment of the present invention will be described.
FIG. 11 is a cross-sectional view showing a piezoelectric element manufactured using film forming raw material powder according to an embodiment of the present invention. As shown in FIG. 11, the first electrode 22 is formed on the substrate 21, and the piezoelectric body 23 is formed on the first electrode 22 by the AD method using the film forming raw material powder according to the present embodiment. A second electrode 24 is formed on the piezoelectric body 23. Here, the first electrode 22, the piezoelectric body 23, and the second electrode 24 constitute a piezoelectric element 25. When a voltage is applied between the first electrode 22 and the second electrode 24, the piezoelectric body 23 expands and contracts due to the piezoelectric effect. The piezoelectric element 25 as shown in FIG. 11 is used for various applications such as a piezoelectric actuator, a piezoelectric pump, an inkjet printer head, and an ultrasonic transducer.

FIG. 12 is a perspective view showing an internal structure of an ultrasonic probe using the piezoelectric element shown in FIG. 11 as a vibrator.
As shown in FIG. 12, the ultrasonic probe 30 includes a plurality of transducers 25, an acoustic matching layer 31, and a backing material 32. In FIG. 12, a plurality of transducers 25 are two-dimensionally arrayed, but these transducers 25 have the same structure as shown in FIG. However, in FIG. 12, the second electrode 24 is formed as a common electrode common to a plurality of transducers 25 arranged in a two-dimensional array.

  In the ultrasonic probe 30, the transducer 25 generates an ultrasonic wave by a piezoelectric effect in accordance with a drive signal supplied from the ultrasonic diagnostic apparatus main body, and transmits the ultrasonic wave to the subject. On the other hand, the transducer 25 receives the ultrasonic echo reflected by the subject, and converts the ultrasonic echo into a reception signal by the piezoelectric effect. The acoustic matching layer 31 increases the propagation efficiency of ultrasonic waves by matching the acoustic impedance between the transducer 25 and the subject. The backing material 32 attenuates unnecessary ultrasonic waves generated from the vibrator 25.

  The present invention can be used in an aerosol deposition method in which a raw material is deposited on a substrate by spraying an aerosol in which the raw material powder is dispersed toward the substrate.

It is a flowchart which shows the manufacturing method of the film structure which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming apparatus used in the manufacturing method of the film | membrane structure which concerns on one Embodiment of this invention. It is a figure which shows the SEM photograph of the AD film | membrane of an Example. 6 is a view showing an SEM photograph of an AD film of Comparative Example 1. FIG. 6 is a view showing an SEM photograph of an AD film of Comparative Example 2. FIG. It is a figure which shows the hysteresis characteristic of the polarization value P about AD film shown in FIG. It is a figure which shows the hysteresis characteristic of the polarization value P about AD film shown in FIG. It is a figure which compares the electrical property of AD film shown in FIGS. It is a figure which shows the SEM photograph of a bulk ceramic. FIG. 10 is a diagram comparing the densities of the bulk ceramic shown in FIG. 9 and the two types of AD films shown in FIGS. 3 and 5 respectively. It is sectional drawing which shows the piezoelectric element manufactured using the film-forming raw material powder which concerns on one Embodiment of this invention. FIG. 12 is a perspective view showing an internal structure of an ultrasonic probe using the piezoelectric element shown in FIG. 11 as a vibrator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aerosol production | generation chamber 2 Shaking table 3 Hoisting gas nozzle 3a, 4a Pressure adjustment part 4 Pressure adjustment nozzle 5 Aerosol conveyance pipe 6 Deposition chamber 7 Nozzle 8 Substrate stage 9 Exhaust pipe 10 Control part 11 Raw material powder for film formation 12, 21 Substrate 13 Membranes 22, 24 Electrode 23 Piezoelectric body 25 Vibrator 30 Ultrasonic probe 31 Acoustic matching layer 32 Backing material

Claims (14)

In the method of producing raw material powder used for forming a film having the composition of raw material powder by spraying the raw material powder toward the substrate,
A nitrate of at least one element selected from the group consisting of lead (Pb), zinc (Zn), cerium (Ce), copper (Cu), ytterbium (Yb), dysprosium (Dy), and nickel (Ni); Using sulfates, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and A step (a) of fixing a grain growth aid containing at least one composition selected from nickel oxide (NiO) to the surface of the base material particles containing a lead-based piezoelectric material;
A step (b) of decomposing remaining nitrates or sulfates or nitrate ions or sulfate ions contained therein by applying energy to the grain growth aid fixed to the surface of the base material particles;
A method for producing a raw material powder for film formation comprising: Step (a) is
A ternary lead zirconate titanate represented by the general formula Pb (Ni, Nb) O ₃ —PbZrO ₃ —PbTiO ₃ ;
Excess lead (Pb) than the stoichiometric ratio with respect to the composition of the ternary lead zirconate titanate,
Zinc (Zn);
At least one rare earth element selected from cerium (Ce), ytterbium (Yb), and dysprosium (Dy);
The manufacturing method of the raw material powder for film forming of Claim 1 including preparing the base material particle | grains containing these.   The manufacturing method of the raw material powder for film formation of Claim 1 or 2 with which a process (c) includes heating the said grain growth adjuvant fixed to the surface of the said base material particle.   The manufacturing method of the raw material powder for film formation of Claim 1 or 2 with which a process (c) includes irradiating electromagnetic waves to the said grain growth adjuvant fixed to the surface of the said base material particle. In the method of manufacturing a film structure that forms a film having a composition of raw material powder by spraying the raw material powder toward the substrate,
A nitrate of at least one element selected from the group consisting of lead (Pb), zinc (Zn), cerium (Ce), copper (Cu), ytterbium (Yb), dysprosium (Dy), and nickel (Ni); Using sulfates, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and A step (a) of fixing a grain growth aid containing at least one composition selected from nickel oxide (NiO) to the surface of the base material particles containing a lead-based piezoelectric material;
A step (b) of decomposing remaining nitrates or sulfates or nitrate ions or sulfate ions contained therein by applying energy to the grain growth aid fixed to the surface of the base material particles;
(C) forming the film having the composition of the raw material powder directly or indirectly on the substrate by spraying the raw material powder obtained in the step (b) in an aerosol state toward the substrate;
A step (d) of growing crystal grains in the film by performing a heat treatment on the film structure;
The manufacturing method of the film | membrane structure which comprises this. Step (a) is
A ternary lead zirconate titanate represented by the general formula Pb (Ni, Nb) O ₃ —PbZrO ₃ —PbTiO ₃ ;
Excess lead (Pb) than the stoichiometric ratio with respect to the composition of the ternary lead zirconate titanate,
Zinc (Zn);
At least one rare earth element selected from cerium (Ce), ytterbium (Yb), and dysprosium (Dy);
The manufacturing method of the film | membrane structure of Claim 5 including preparing the base material particle | grains containing these.   The method for producing a film structure according to claim 5 or 6, wherein the step (c) includes forming a film containing crystal grains having an average particle diameter of 10 nm to 500 nm. In the raw material powder used to form a film having the composition of the raw material powder by spraying the raw material powder toward the substrate,
Base material particles containing lead-based piezoelectric material;
Lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and nickel oxide (NiO) A grain growth aid comprising at least one composition selected from among the above, and fixed so as to cover the surface of the base material particles;
A raw material powder for film formation comprising: The base material particles are
A ternary lead zirconate titanate represented by the general formula Pb (Ni, Nb) O ₃ —PbZrO ₃ —PbTiO ₃ ;
Excess lead (Pb) than the stoichiometric ratio with respect to the composition of the ternary lead zirconate titanate,
Zinc (Zn);
At least one rare earth element selected from cerium (Ce), ytterbium (Yb), and dysprosium (Dy);
The film-forming raw material powder according to claim 8, comprising:   The raw material powder for film formation according to claim 8 or 9, which has an average particle size of 0.1 µm or more and 10 µm or less. In the film structure manufactured by forming the film having the composition of the raw material powder by spraying the raw material powder toward the substrate,
(A) a substrate;
(B) a film formed directly or indirectly on the substrate, including crystal grains containing a lead-based piezoelectric material and having an average particle diameter of 10 nm to 500 nm, and lead oxide (PbO), zinc oxide (ZnO) ), Cerium oxide (CeO ₂ ), copper oxide (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and nickel oxide (NiO). A film containing a grain growth aid comprising:
A membrane structure comprising: The crystal grains of the film are
A ternary lead zirconate titanate represented by the general formula Pb (Ni, Nb) O ₃ —PbZrO ₃ —PbTiO ₃ ;
Excess lead (Pb) than the stoichiometric ratio with respect to the composition of the ternary lead zirconate titanate,
Zinc (Zn);
At least one rare earth element selected from cerium (Ce), ytterbium (Yb), and dysprosium (Dy);
The membrane structure according to claim 11, comprising: In the piezoelectric element manufactured by forming the film having the composition of the raw material powder by spraying the raw material powder toward the substrate,
(A) a first electrode;
(B) A piezoelectric film formed on the first electrode, including crystal grains containing a lead-based piezoelectric material, lead oxide (PbO), zinc oxide (ZnO), cerium oxide (CeO ₂ ), oxidation The grain growth aid comprising at least one composition selected from copper (CuO), ytterbium oxide (Yb ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and nickel oxide (NiO). A piezoelectric film;
(C) a second electrode formed on the piezoelectric film;
A piezoelectric element comprising: The crystal grains of the piezoelectric film are
A ternary lead zirconate titanate represented by the general formula Pb (Ni, Nb) O ₃ —PbZrO ₃ —PbTiO ₃ ;
Excess lead (Pb) than the stoichiometric ratio with respect to the composition of the ternary lead zirconate titanate,
Zinc (Zn);
At least one rare earth element selected from cerium (Ce), ytterbium (Yb), and dysprosium (Dy);
The piezoelectric element according to claim 13, comprising: