Abstract:
Disclosed is a method of manufacturing an electromechanical transducer element including a first process of hydrophobizing a first area of an electrode by forming a self-assembled monolayer film; a second process of applying a sol-gel solution onto a predetermined second area of the electrode so as to produce a complex oxide; a third process of producing the complex oxide by calcining the electrode; a fourth process of acid-washing the electrode on which the complex oxide has been produced; a fifth process of hydrophobizing the first area of the acid-washed electrode by forming the self-assembled monolayer film; a sixth process of applying the sol-gel solution onto the predetermined second area; and a seventh process of producing the complex oxide by calcining the electrode.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present invention relate to a method of manufacturing electromechanical transducer elements, the electromechanical transducer elements, discharging heads, and inkjet recording devices. 
         [0003]    2. Description of the Related Art 
         [0004]    Inkjet recording devices can print at high speed while generating very little noise. In addition, for such inkjet recording devices, there is a large degree of freedom of selecting ink, and less expensive plain paper may be utilized. Therefore, the inkjet recording devices have been widely adopted as image forming devices such as printers, facsimile machines, and copiers. 
         [0005]    A discharge head for an inkjet recording device includes nozzles for discharging ink, liquid chambers that communicates with the corresponding nozzles, and pressure generating units that cause the ink in the corresponding liquid chambers to be discharged. It has been known that an electromechanical transducer element can be utilized as the pressure generating unit. 
         [0006]    Patent Document 1 (Japanese Patent Laid-Open Application No. 2011-9726) discloses a method of manufacturing electromechanical transducer elements. The method includes a first manufacturing process, a second manufacturing process, and a third manufacturing process. In the method, the first, second, and third manufacturing processes are repeated. In the first manufacturing process, a self-assembled film is formed on a predetermined area of an electrode, and the self-assembled film is hydrophobized. In the second manufacturing process, a sol-gel solution is applied to an area on the electrode where the self-assembled film has not been formed. In the third manufacturing process, a complex oxide is produced by drying, thermally decomposing, and crystallizing the electrode on which the sol-gel solution has been applied. 
         [0007]    However, there is a problem such that, when the number of times of generating the complex oxide is increased, it becomes difficult to hydrophobize the electrode. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the present invention have been developed in view of the above problem. An objective of the embodiments of the present invention is to provide a method of manufacturing electromechanical transducer elements where an electrode can be hydrophobized even if a number of times of generating a complex oxide is increased; electromechanical transducer elements manufactured by the method; discharging heads including the electromechanical transducer elements; and inkjet recording devices including the electromechanical transducer elements. 
         [0009]    In one aspect, there provided a method of manufacturing an electromechanical transducer element. The method includes a first process of hydrophobizing a first area of an electrode by forming a self-assembled monolayer film on the first area, wherein a complex oxide film has been formed on a predetermined second area of the electrode, and the complex oxide film has not been formed on the first area of the electrode on which the self-assembled monolayer film is formed; a second process of applying a sol-gel solution onto the predetermined second area of the electrode where the self-assembled monolayer film has not been formed, wherein the sol-gel solution is adjusted to produce the complex oxide; a third process of producing the complex oxide by calcining the electrode to which the sol-gel solution has been applied; a fourth process of acid-washing the electrode on which the complex oxide has been produced; a fifth process of hydrophobizing, by forming the self-assembled monolayer film, the first area of the acid-washed electrode on which the complex oxide film has not been formed; a sixth process of applying the sol-gel solution onto the predetermined second area where the self-assembled monolayer film has not been formed, wherein the sol-gel solution is adjusted to produce the complex oxide; and a seventh process of producing the complex oxide by calcining the electrode on which the sol-gel solution has been applied. 
         [0010]    In another aspect, there is provided an electromechanical transducer element that is formed by the method of manufacturing the electromechanical transducer element. 
         [0011]    In another aspect, there is provided a discharging head including the electromechanical transducer element. 
         [0012]    In another aspect, there is provided an inkjet recording device including the discharging head. 
         [0013]    According to the embodiments of the present invention, the method of manufacturing the electromechanical transducer element can be provided where the electrode can be hydrophobized even if the number of times of generating the complex oxide is increased. Additionally, there can be provided the electromechanical transducer elements manufactured by the method, discharging heads including the electromechanical transducer elements, and the inkjet recording devices including the electromechanical transducer elements. 
         [0014]    Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIGS. 1A-1D  are cross-sectional views illustrating a method of manufacturing an electromechanical transducer element according to an embodiment; 
           [0016]      FIG. 2  is a perspective view showing an example of a self-assmbled monolayer film forming apparatus; 
           [0017]      FIG. 3  is a cross-sectional view showing an example of a discharging head according to the embodiment; 
           [0018]      FIG. 4  is a cross-sectional view showing another example of the discharging head according to the embodiment; 
           [0019]      FIG. 5A  is a perspective view showing an inkjet recording ice according to the embodiment; 
           [0020]      FIG. 5B  is a side view showing the inkjet recording device according to the embodiment; 
           [0021]      FIG. 6  is a diagram showing an analyzing result of an O 1s  peak by an X-ray photoelectron spectroscopy; 
           [0022]      FIG. 7  is a P-E hysteresis loop of a complex oxide film laminated body according to the embodiment; and 
           [0023]      FIG. 8  shows a relationship between a number of processes for forming the complex oxide films (and thereby forming the complex oxide film laminated body) and a contact angle of water on an area of a common electrode where a self-assembled monolayer film has been formed but no complex oxide films have been formed. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    Hereinafter, an embodiment of the present invention will be explained while referring to the accompanying figures. 
         [0025]      FIG. 1  shows an example of a method of manufacturing an electromechanical transducer film according to the embodiment. 
         [0026]    A complex oxide film  12  has been formed on a predetermined area of a common electrode  11  (cf.  FIG. 1A ). A self-assembled monolayer (SAM) film  13  is formed on an area on the common electrode  11  where the complex oxide film  12  has not been formed, and thereby hydrophobizing the area on the common electrode  11  where the complex oxide film  12  has not been formed (cf.  FIG. 1B ). 
         [0027]    A material of the common electrode  11  is not limited, provided that the self-assembled monolayer film  13  can be formed on the common electrode  11 . Examples of the material of the common electrode  11  include a platinum group metal such as platinum, rhodium, ruthenium, and iridium; and a platinum group alloy such as a platinum-rhodium alloy. Especially, platinum is preferable. 
         [0028]    The common electrode  11  may be a laminated body such that a film of a platinum group metal or a film of a platinum group alloy is formed on a film of a conductive metal oxide. 
         [0029]    The conductive metal oxide is not limited to a particular material. However, examples of the conductive metal oxide include SrRuO 3 , CaRuO 3 , (Sr 1-x Ca x )RuO 3 , LaNiO 3 , SrCoO 3 , (La 1-y Sr y ) (Ni 1-y Co y )O 3 , IrO 2 , and RuO 2 . 
         [0030]    Thickness of the common electrode  11  is usually in a range from 0.05 μm to 2 μm. 
         [0031]    The common electrode  11  is usually formed on a substrate such as a silicone wafer. However, the common electrode  11  itself may be the substrate. 
         [0032]    The method of forming the common electrode  11  on the substrate is not Limited to a particular method. However, examples of the forming the common electrode  11  on the substrate include the sputtering method, and the evaporation method. 
         [0033]    The method of forming the complex oxide film  12  on a predetermined area of the common electrode  11  is not limited to a particular method. However, examples of the method include a method in which the complex oxide film  12  is formed by etching the unnecessary complex oxide film after forming a photo-resist pattern on the common electrode  11 , where the complex oxide film is formed on the entire surface of the common electrode  11 ; and a method in which the complex oxide film  12  is formed after forming a photo-resist pattern on the common electrode  11 . 
         [0034]    The method of forming the complex oxide film  12  on the common electrode  11  is not limited to a particular method. However, examples of the method of forming the complex oxide film  12  on the common electrode  11  include the sputtering method and the evaporation method. 
         [0035]    When the complex oxide film  12  is formed on the entire surface of the common electrode  11 , a sol-gel solution is applied onto the common electrode  11  by using the spin coating method, and subsequently the common electrode  11  may be calcined. 
         [0036]    The photo-resist is not limited to a particular photo-resist. However, examples of the photo-resist include polycinnamic acid vinyl; a cyclized rubber-bisazide resist; a negative resist included in cross-link-type chemically amplified resists, such as a resist formed of polyvinyl phenol/a crosslinking agent such as melamine/and an acid-generating agent; a quinone diazide-novolak resin-based resist; a positive resist included in protection group desorption or dissolution preventing type chemically amplified resists, such as a resist formed of an acetalized polyvinylphenol and an acid-generating agent. 
         [0037]    The method of applying the photo-resist is not limited to a particular method. However, for example, the spin-coating method, the dipping method, the cast method, the spray coating method, the die coating method, the screen printing, and a doctor blade method can be considered. 
         [0038]    The thickness of the photo-resist is usually in a range from 0.5 μm to 10 μm. 
         [0039]    A light source that is utilized for exposing light to the photo-resist is not limited to a particular light source. However, for example, a halogen lamp, a high-pressure mercury lamp, a UV lamp, and an excimer laser may be considered. 
         [0040]    The light exposed to the photo-resist preferably has a wavelength in a range from 100 nm to 500 nm. The ultraviolet light is especially preferable. 
         [0041]    A developer used for developing the photo-resist is not limited to a particular developer. However, for example, water, an alkali aqueous solution, and an organic solvent may be considered. Two or more of them may be used at the same time. 
         [0042]    The method of etching the unnecessary complex oxide film is not limited to a particular method. However, the argon plasma processing may be considered, for example. 
         [0043]    The solvent used for removing the photo-resist not limited to a particular solvent. However, for example, acetone, tetrahydrofuran, and N-methylpyrrolidone may be considered. 
         [0044]    Additionally, the complex oxide film  12  may be formed on the predetermined area of the common electrode  11  by using a method described in FIGS. 1-5 of Patent Document 1. 
         [0045]    Further, after forming the complex oxide film  12  on the common electrode  11 , the common electrode  11  may be acid washed as described later. 
         [0046]    The complex oxide included in the complex oxide film  12  is not limited to a particular material, provided that the electromechanical transducer film may be formed with the complex oxide. However, for example, a chemical compound expressed by a general formula ABO 3  may be considered. In the formula, A is one or more elements selected from a group including Pb, Ba, and Sr. B is one or more elements selected from a group including Ti, Zr, Sn, Ni, Zn, Mg, and Nb. Especially, lead zirconate titanate (PZT) is preferable. 
         [0047]    Lead zirconate titanate is a solid solution of lead zirconate (PbZrO 3 ) and lead titanate (PbTiO 3 ). The chemical property of lead zirconate titanate depends on a ratio between the lead zirconate and lead titanate. From the viewpoint of the electromechanical transducing property, Pb(Zr 0.53 , Ti 0.47 )O 3  ie preferable. 
         [0048]    Specific examples of the complex oxide other than lead zirconate titanate include, for example, barium titanate, (Pb 1-x Ba x ) (Zr, Ti)O 3 , and (Pb 1-x Sr x ) Zr, Ti)O 3 . 
         [0049]    The thickness of the complex oxide film  12  is usually 100 nm. When the thickness of the complex oxide film  12  becomes large, it is possible that cracking occurs during the baking process of a complex oxide laminated body, which will be described later. 
         [0050]    When the self-assembled monolayer film  13  is formed on the common electrode  11 , it is preferable that a thiol or a solution of a thiol be applied from a nozzle to the common electrode  11 . 
         [0051]    The thiol is not limited to a specific thiol, provided that the self-assembled monolayer film  13  may be formed on the common electrode  11  with the thiol. However, for example, a straight chain alkane thiol having a carbon number of 6-30 may be considered. 
         [0052]    The method of applying the thiol or the the thiol is not limited to a specific method. However, for example, the dipping method may be considered. 
         [0053]    The solvent included in the solution of the thiol is not limited to a particular solvent. However, for example, ethanol, isopropanol, and toluene may be considered. 
         [0054]    After the thiol or the solution of the thiol has been applied to the common electrode  11 , the common electrode  11  is washed with a cleaning solution. 
         [0055]    The cleaning solution is not limited to a particular cleaning solution, provided that the thiol that is not forming the self-assembled monolayer film  13  can be removed with the cleaning solution. For example, ethanol, isopropanol, and toluene may be considered. 
         [0056]    The method of washing the common electrode  11 , to which the thiol or the solution of the thiol has been applied, with the cleaning solution is not limited to a particular method. However, for example, a method may be considered in which the cleaning solution is applied from a nozzle onto the common electrode  11 . It is preferable to spray the cleaning solution, to which ultrasonic waves have been applied, from the nozzle to the common electrode  11 . The reason is that the thiol that is not forming the self-assembled monolayer film  13  may easily be removed with the cleaning solution in such a condition. 
         [0057]    The frequency range of the ultrasonic waves applied to the cleaning solution is usually from 20 kHz to 1 MHz. 
         [0058]    Next, a sol-gel solution  14  is applied to an area on the common electrode  11  where the self-assembled monolayer film  13  has not been formed (cf.,  FIG. 1C ). The complex oxide can be formed with the sol-gel solution  14 . 
         [0059]    When the complex oxide is lead zirconate titanate, the sol-gel solution  14  may be prepared by dissolving lead acetate, zirconate alkoxide, titanalkoxide into methoxyethanol. 
         [0060]    The sol-gel solution  14  may further include a stabilizing agent such as acetylacetone, acetic acid, and diethanolamine, so as to prevent a metalalkoxide from being hydrolyzed by moisture in the air. 
         [0061]    When the complex oxide is barium titanate, the sol-gel solution  14  may be prepared by dissolving barium alkoxide and titanalkoxide into methoxyethanol. 
         [0062]    The method of applying the sol-gel solution  14  is not limited to a particular method. However, an inkjet method can be considered, for example. 
         [0063]    Next, the common electrode  11  to which the sol-gel solution  14  has been applied is calcined to form a complex oxide film  14 ′, and thereby forming a complex oxide film laminated body  15  (cf.  FIG. 15 ). At this time, the self-assembled monolayer film  13  is removed. 
         [0064]    The temperature for calcining the common electrode  11  to which the sol-gel solution  14  has been applied is usually in a range from 300 degrees Celsius to 1400 degrees Celsius. It is preferable that the temperature be in a range from 450 degrees Celsius to 1200 degrees Celsius. At this time, the temperature may be increased stepwise. 
         [0065]    The time interval for calcining the common electrode  11  to which the sol-gel solution  14  has been applied is usually in a range from 2 hours to 24 hours. 
         [0066]    The atmosphere for calcining the common electrode to which the sol-gel solution  11  has been applied may be any one of an inert gas atmosphere and an atmosphere including oxygen such as the air. At this time, the pressure of the atmosphere may be normal pressure. Alternatively, the pressure may be reduced. 
         [0067]    The thickness of the complex oxide film  14 ′ is usually about 100 nm. When the thickness of the complex oxide film  14  becomes too large, cracking may occur during baking of the complex oxide film laminated body (which will be described later). 
         [0068]    Subsequently, the electrode  11 , on which the complex oxide film laminated body  15  has been formed, is acid-washed. 
         [0069]    An acid or a solution of an acid that is utilized for acid-washing the electrode  11 , on which the complex oxide film laminated body  15  has been formed, is not limited to a specific acid or a specific solution of an acid. However, for example, hydrogen chloride or acetic acid may be utilized. 
         [0070]    The method of acid-washing the electrode  11 , on which the complex oxide film laminated body  15  has been formed, is not limited to a specific method. However, for example, a method of spraying the acid or the solution of the acid from a nozzle to the common electrode  11  can be utilized. 
         [0071]    It is preferable that the pH of the acid or the solution of the acid at 25 degrees Celsius be in a range from 2 to 5. It is more preferable that the pH be in a range from 2 to 4, and it is most preferable that the pH be in a range from 3 to 4. When the pH of the acid or the solution of the acid at 25 degrees Celsius is less than 2, dielectric loss of the complex oxide film laminated body is increased, and the electromechanical transducing property of the electromechanical transducer element may be degraded. On the other hand, when the pH of the acid or the solution of the acid at 25 degrees Celsius is greater than 5, an oxide may remain on the surface of the common electrode  11 , and it may become difficult to hydrophobize the common electrode  11 . Therefore, the form accuracy of the complex oxide film laminated body may be lowered. 
         [0072]    The acid-washed common electrode  11  is usually washed by a cleaning solution. 
         [0073]    The cleaning solution is not limited to a specific cleaning solution, provided that the cleaning solution can remove the acid. However, examples of the cleaning solution include water, isopropanol, and ethanol. 
         [0074]    The method of washing the acid-washed common electrode  11  with the cleaning solution is not limited to a specific method. However, for example, a method can be considered in which the cleaning solution is sprayed from a nozzle to the common electrode  11 . 
         [0075]    Subsequently, similar to the case of  FIGS. 1B-1D , another complex oxide film  14 ′ is laminated on the complex oxide film laminated body  15 . 
         [0076]    After the common electrode  11 , on which the complex oxide film laminated body  15  has been formed, is acid-washed, the process of laminating the complex oxide film  14 ′ is repeated until the thickness of the complex oxide film laminated body  15  becomes a predetermined value. At this time, upon the thickness of the complex oxide film laminated body  15  becoming the predetermined value, the complex oxide film laminated body  15  is baked. 
         [0077]    The temperature for baking the common electrode  11 , on which the complex oxide film laminated body  15  has been formed, is usually in a range from 300 degrees Celsius to 1400 degrees Celsius. It is preferable that the temperature be in a range from 450 degrees Celsius to 1200 degrees Celsius. At this time, the temperature may be increased stepwise. 
         [0078]    The time interval for baking the common electrode  11 , on which the complex oxide film laminated body  15  has been formed is usually in a range from 3 minutes to 24 hours. 
         [0079]    The atmosphere for baking the common electrode  11 , on which the complex oxide film laminated body  15  has been formed may be any one of an inert gas atmosphere or an atmosphere including oxygen such as the air. At this time, the pressure of the atmosphere may be normal pressure. Alternatively, the pressure may be reduced. 
         [0080]    The thickness of the complex oxide film laminated body  15  is usually in a range from 1 μm to 5 μm. 
         [0081]    Subsequently, an individual electrode is formed on the complex oxide film laminated body  15 , and thereby the electromechanical transducer element according to the embodiment is obtained. 
         [0082]    A material of the individual electrode is not limited to a specific material. However, examples of the material of the individual electrode include a platinum group metal such as platinum, rhodium, ruthenium, and iridium; a platinum group alloy such as a platinum-rhodium alloy; and a conductive metal oxide such as SrRuO 3 , CaRuO 3 , (Sr 1-x Ca x )RuO 3 , LaNiO 3 , SrCoO 3 , (La 1-y Sr y )(Ni 1-y Co y )O 3 , IrO 2 , and RuO 2 . 
         [0083]    The thickness of the individual electrode is usually in a range from 0.05 μm to 2 μm. 
         [0084]    A method of forming the individual electrode on the complex oxide film laminated body  15  is not limited to a specific method. However, examples of the method of forming the individual electrode include a method similar to the method of forming the complex oxide film  12  on the predetermined area of the common electrode  11 ; and a method that is similar to the method shown in  FIGS. 1B-1D . 
         [0085]    After forming the complex oxide film laminated body  15  on the common electrode  11 , the common electrode  11  may be acid-washed as described above, prior to forming the individual electrode. 
         [0086]      FIG. 2  shows an example of a self-assembled monolayer film forming apparatus  20  that is utilized for forming the self-assembled monolayer film  13 . The self-assembled monolayer film forming apparatus includes an acid-washing chamber  21 ; a self-assembled monolayer film forming chamber  22 ; a hot plate  23 ; an aligner  24 ; and a robot arm  25 . 
         [0087]    The acid-washing chamber  21  includes a spinner chuck  21   a ; an acid nozzle  21   b ; and a cleaning solution nozzle  21   c . Further, the self-assembled monolayer film forming chamber  22  includes a spinner chuck  22   a ; a self-assembled monolayer film nozzle  22   b ; a cleaning solution nozzle  22   c : and an ultrasonic generator  22   d.    
         [0088]    A method of fixing the common electrode  11  on the spinner chucks  21   a  and  22   a  is not limited to a particular method. However, a vacuum method and a pinning method may be considered. Especially, the vacuum method is preferable. 
         [0089]    The hot plate  23  is used for drying the common electrode  11 , after the common electrode  11  has been acid-washed. 
         [0090]    The aligner  24  is used for aligning the disposed common electrode  11  to a predetermined position. 
         [0091]    The robot arm  25  is used for moving the common electrode  11 . 
         [0092]    Next, there will be explained the method of forming the self-assembled monolayer film  13  on the area of the common electrode  11  where the complex oxide film laminated body  15  is not formed. Here, the complex oxide film laminated body  15  has been formed on the other area of the common electrode  11 . 
         [0093]    First, the common electrode  11  is disposed in the aligner  24 . Here, the complex oxide film  12  has been formed on the predetermined area of the common electrode  11 . The aligner  24  aligns the common electrode  11  to a predetermined position. Subsequently, the robot arm  25  moves the common electrode  11  inside the acid-washing chamber  21 , and fixes the common electrode  11  to the spinner chuck  21   a . Further, after the common electrode  11  has been acid-washed by spraying it with the acid or the solution of the acid from the acid nozzle  21   b , the common electrode  11  is washed by spraying it with the cleaning solution from the washing liquid nozzle  21 , while the common electrode  11  is rotated. Then, the robot arm  25  moves the common electrode  11  onto the hot plate  23 . The common electrode  11  is dried. Further, the robot arm  25  moves the common electrode  11  inside the self-assembled monolayer film forming chamber  22 , and the robot arm  25  fixes the common electrode to the spinner chuck  22   a . After the self-assembled monolayer film  13  has been formed on the common electrode  11  by spraying it with the thiol or the solution of the thiol from the self-assembled monolayer film nozzle  22   b , the common electrode  11  is washed by spraying it with the cleaning solution from the cleaning solution nozzle  22   c , while the common electrode  11  is rotated. At this time, the ultrasonic generator  22   d  applies ultrasonic waves to the cleaning solution. After that, the robot arm  25  moves the common electrode  11  to the aligner  24 . Then, the common electrode  11  is retrieved. 
         [0094]    Additionally, when the self-assembled monolayer film  13  is formed on the area of the common electrode  11  where the complex oxide film  12  has not been formed (the complex oxide film  12  has been formed on the other area of the common electrode), the self-assembled monolayer film forming apparatus  20  may be used. 
         [0095]    Furthermore, after the complex oxide film laminated body  15  has been formed on the common electrode  11 , the self-assembled monolayer film forming apparatus  20  may be used for acid-washing the common electrode  11 , prior to forming the individual electrode. 
         [0096]    The discharging head according to the embodiment is not limited to a particular discharging head, provided that the discharging head includes the electromechanical transducer element according to the embodiment. However, examples of the discharging head include an inkjet head and a micropump. 
         [0097]      FIG. 3  shows an inkjet head  30  as an example of the discharging head according to the embodiment. In the inkjet head  30 , a liquid chamber  34  has been formed by laminating a nozzle plate  31  in which a nozzle  31   a  has been formed, a liquid chamber substrate  32 , and an oscillation plate  33 , in this order. Further, in the inkjet head  30 , an electromechanical transducer element  10  has been formed by laminating, through an adhesive layer  35 , the common electrode  11 , a complex oxide film laminated body  16 , and the individual electrode  17 , in this order, at an area on the oscillation plate  33  that corresponds to the liquid chamber  34 . 
         [0098]    A material that forms the nozzle plate  31  is not limited to a particular material. However, examples of the material of the nozzle plate  31  include a stainless steel and a polyimide. 
         [0099]    A method of forming the liquid chamber substrate  32  is not limited to a particular method. However, for example, a method may be considered in which a silicone wafer that forms the oscillation plate  33 , the adhesive layer  35 , and the electromechanical transducer element  10  is etched. 
         [0100]    The thickness of the liquid chamber substrate  32  is usually in a range from 100 μm to 600 μm. 
         [0101]    Examples of a material of the oscillation plate  33  include silicon oxide; silicon nitride; silicon nitride oxide; aluminum oxide; zirconium oxide; iridium oxide; ruthenium oxide; tantalum oxide; hafnium oxide; osmium oxide; rhenium oxide; rhodium oxide; and palladium oxide. Two or more of the above materials may be used at the same time. 
         [0102]    A method of forming the oscillation plate  33  is not limited to a particular method. However, for example, the sputtering method and the evaporation method may be considered. 
         [0103]    The thickness of the oscillation plate  33  is usually in a range from 0.1 μm to 10 μm. It is preferable that the thickness be in a range from 0.5 μm to 3 μm. 
         [0104]    A material of the adhesive layer  35  is not limited to a particular material. However, for example, titanium; tantalum; titanium oxide; tantalum oxide; titanium nitride; and tantalum nitride may be considered. Two or more of the above materials may be used at the same time. 
         [0105]    Here, the adhesive layer  35  may be omitted depending on the cases. 
         [0106]      FIG. 4  shows an inkjet head  30 ′ as another example of the discharging head according to the embodiment. The inkjet head  30 ′ has a configuration that is the same as that of the inkjet head  30 , except for that the plural electromechanical transducer elements  10 , the nozzles  31   a , and the liquid chambers  34  are arranged in a line. 
         [0107]      FIGS. 5A and 5B  show an example of an inkjet recording device according to the embodiment.  FIG. 5A  is a perspective view of the inkjet recording device.  FIG. 5B  is a side view of the recording device. 
         [0108]    A main body  101  of the inkjet recording device  100  includes a carriage that can be moved in a main scanning direction; the inkjet head  30  mounted on the carriage  102 ; and an ink cartridge  103 . Additionally, a paper feed cassette  104  that can store sheets of paper P can be detachably attached to the inkjet recording device  100  from a front side of a lower portion of the main body  101 , and the inkjet recording device  100  includes an openable and closeable manual feed tray  105  for manually feeding the sheets of paper P. Further, after an image has been formed on the sheet of paper P that has been fed from the paper feed cassette  104  or from the manual feed tray  105 , the inkjet recording device  100  discharges the sheet of paper P on a paper discharge tray  106 . 
         [0109]    The carriage  102  is held by a main guide rod  107  and a sub-guide rod  108 , so that carriage  102  can be slid in the main scanning direction. The main guide rod  107  and the sub-guide rod  108  are supported by left and right side plates not shown). The inkjet head  30  that discharges yellow (Y) ink, cyan (C) ink, magenta (M) ink, and black (Bk) ink is attached to the carriage  102 , so that the inkjet head  30 ′ discharges the ink downward. At this time, the inkjet head  30 ′ is arranged so that the plural electromechanical transducer elements  10 , the nozzles  31   a , and the liquid chambers  34  are arranged in a line in a direction that intersects the main scanning direction. Additionally, the ink cartridges  103  are replaceably attached to the carriage  102 . The ink cartridges  103  supply the ink having the corresponding colors to the inkjet head  30 ′. 
         [0110]    Each of the ink cartridge  103  includes an air inlet (not shown) that communicates with the air outside and that is formed at an upper portion of the ink cartridge  103 ; a supply port (not shown) that supplies the ink to the inkjet head  30 ′ and that is formed at a lower portion of the ink cartridge  103 ; and a porous body (not shown) that is filled with the ink and that is disposed inside the ink cartridge  103 . At this time, the ink supplied to the inkjet head  30 ′ is maintained to have slightly negative pressure by a capillary force of the porous body. 
         [0111]    Here, instead of arranging the inkjet head  30 ′ that discharges the ink in the corresponding colors, the inkjet head  30  that discharges the yellow ink, the inkjet head  30  that discharges the cyan ink, the inkjet head  30  that discharges the magenta ink, and the inkjet head  30  that discharges the black ink may be attached to the carriage  102 . 
         [0112]    A portion of the carriage  102  at a downstream side in the direction in which the sheet of paper P is conveyed is slidably supported by the main guide rod  107 . Another portion of the carriage  102  at an upstream side in the direction in which the sheet of paper P is conveyed is slidably supported by the sub-guide rod  108 . A timing belt  112  is suspended between a drive pulley  110  and a driven pulley  111 . The drive pulley  110  is rotationally driven by a main scanning motor  109 . The carriage  102  is fixed to the timing belt  112 . Therefore, the carriage  102  can be reciprocated in the main scanning direction by the rotation of the main scanning motor  109 . 
         [0113]    The inkjet recording device  100  includes a paper feed roller  113  and a friction pad  114  that separate the sheets of paper P and that feed the sheets of paper P on a sheet-by-sheet basis; a guide member  115  that guides the sheet of paper P that has been fed; a conveyance roller  116  that conveys the sheet of paper P which has been fed, while inverting the sheet of paper P; a conveyance roller  117  that is pressed onto a circumferential surface of the conveyance roller  116 ; and a tip roller  118  that defines an angle in which the sheet of paper P is sent out from the conveyance roller  116 , so as to convey the sheets of paper P stacked on the paper feed cassette  104  to a portion below the inkjet head  30 ′ on a sheet-by-sheet basis. The conveyance roller  116  is rotationally driven by a sub-scanning motor  119  through a sequence of gears (not shown). 
         [0114]    The inkjet recording device  100  includes a guide member  120  that guides the sheet of paper P, which has been conveyed by the conveyance roller  116 , at the position below the inkjet head  30 ′. The inkjet recording device  100  includes a conveyance roller  121  and a spur  122  that are rotationally driven so as to convey the sheet of paper P in a paper discharging direction. The conveyance roller  121  and the spur  122  are disposed at a downstream side of the guide member  120  in the direction in which the sheet of paper P is conveyed. The inkjet recording device  100  further includes guide members  123  and  124  that guide the sheet of paper P that has been conveyed by the conveyance roller  121  and the spur  122 ; and a paper discharging roller  125  and a spur  126  that discharge the sheet of paper P, which has been guided by the guide members  123  and  124 , onto the paper discharge tray  106 . 
         [0115]    When the inkjet recording device  100  records an image on the sheet of paper P, the inkjet recording device  100  drives the inkjet head  30 ′ in accordance with an image signal, while moving the carriage  102 . In this manner, the inkjet recording device  100  causes the inkjet head  30 ′ to discharge the ink onto the staying sheet of paper P and records an amount corresponding to one line. After that, the inkjet recording device  100  repeats the operation to convey the sheet of paper P. When the inkjet recording device  100  receives a recording termination signal or a signal indicating that a rear end of the sheet of paper P reaches a recording area, the inkjet recording device  100  terminates the recording operation, and discharges the sheet of paper P. 
         [0116]    The inkjet recording device  100  includes a recovering device  127  that recovers the inkjet heads  30 ′ from a discharging failure. The recovering device  127  is disposed at a position outside the recording area at the right end side with respect to the moving direction of the carriage  102 . The recovering device  127  includes a cap unit (not shown); a suction unit (not shown); and a cleaning unit (not shown). During a waiting state, the carriage  102  moves toward the recovering device  127 , and the cap unit caps the inkjet head  30 ′. In this manner, the wet conditions of the nozzles are maintained, and a discharging failure caused by drying of the ink is prevented. Further, during recording, the inkjet recording device  100  discharges ink that not related to the recording. In this manner, the viscosity of the ink at the nozzles is homogenized, and a stable discharging capability is maintained. 
         [0117]    When the discharging failure occurs in the inkjet recording device  100 , the nozzles of the inkjet heads  30 ′ are sealed by the cap unit. The ink and bubbles are suctioned from the nozzles by the suction unit through a tube. The ink and dust adhering to the nozzles are removed by a cleaning unit, and thereby the discharging failure is recovered. At this time, the ink suctioned by the suction unit is discharged to a waste ink reservoir (not shown) disposed at a lower portion of the main body  101 , and the ink is absorbed by an ink absorber disposed inside the waste ink reservoir. 
         [0118]    Hereinafter, there will be explained embodiments 1-3 of the present invention. 
       Embodiment 1 
       [0119]    After forming a thermal oxide film (the oscillation plate  33 ) having a thickness of 1 μm on a silicone wafer having a thickness of 725 μm, a titanium film the adhesive layer  35 ) having the thickness of 50 nm was formed by using the sputtering method. Subsequently, a platinum film (the common electrode  11 ) having a thickness of 200 nm was formed by the sputtering method, and after that, a PZT film having a thickness of 100 nm was formed by the sol-gel method. Further, a pattern of the photo-resist TSMR8800 (produced by Tokyo Ohka Kogyo Co., Ltd.) having a thickness of 1.2 μm was formed on the common electrode  11 , and after that, the PZT film (the complex oxide film  12 ) was formed by etching an unnecessary PZT film by the argon plasma processing, and the photo-resist was removed. 
         [0120]    Next, the self-assembled monolayer film  13  was formed on an area of the common electrode  11 , where the complex oxide film  12  had not been formed, by using the self-assembled monolayer film forming apparatus  20  (cf.  FIG. 2 ). Specifically, first, the common electrode  11  was sprayed with a 0.01 mol/L dodecanethiol ethanol solution from the self-assembled monolayer film nozzle  22   b , and the common electrode  11  was allowed to stand for five minutes. Next, the silicon wafer, on which the common electrode  11  had been formed, was washed by spraying it with ethanol from the cleaning solution nozzle  22   c  for two minutes at a rate of 600 mL/min, while the silicon wafer was rotated at 500 rpm so as to remove the dodecanethiol ethanol solution. At that time, the ultrasonic generator  22   d  was applying ultrasonic waves of 1 MHz to ethanol. After that, ethanol adhering to the silicone wafer, on which the common electrode  11  had been formed, was removed by rotating the silicone wafer at 1500 rpm, without spraying it with ethanol from the cleaning solution nozzle  22   c.    
         [0121]    Next, liquid repellency of the common electrode  11  was evaluated by using a contact angle gauge, so as to confirm that the self-assembled monolayer film  13  had been formed on the area of the common electrode  11 , where the complex oxide film  12  had not been formed. It was found that the contact angle of water on the area of the common electrode  11 , where the self-assembled monolayer film  13  had been formed but the complex oxide film  12  had not been formed, was 105 degrees both at the center portion and at a periphery. In addition, it was found that the contact angle of methoxyethanol on the area was 73 degrees both at the center portion and at the periphery. On the other hand, it was found that, prior to forming the self-assembled monolayer film  13 , the contact angles of water and methoxyethanol on the area of the common electrode  11 , where the complex oxide film  12  had not been formed, were less than or equal to 5 degrees both at the center portion and at the periphery. By these results, it was confirmed that the self-assembled monolayer film  13  had been formed both at the center portion and at the periphery of the area of the common electrode  11 , where the complex oxide film  12  had not been formed. 
         [0122]    Furthermore, it was found that the contact angles of water and methoxyethanol on the other area of the common electrode  11 , where the complex oxide film  12  had been formed, were 5 degrees. By these results, it was confirmed that the self-assembled monolayer film  13  had not been formed on the other area of the common electrode  11 , where the complex oxide film  12  had been formed. 
         [0123]    Next, the sol-gel solution  14  was applied to the other area of the common electrode  11 , where the self-assembled monolayer film  13  had not been formed, by using an inkjet device. 
         [0124]    At that time, the sol-gel solution  14  was synthesized as follows. First, lead acetate trihydrate was dissolved into methoxyethanol, and after that a methoxyethanol solution of lead acetate was prepared by dehydrating the resultant solution. Next, tetraisopropoxy titanium and tetraisopropoxy zirconium were dissolved into methoxyethanol and the resultant solution was dehydrated. Then, the dehydrated solution was mixed with the methoxyethanol solution of lead acetate, and thereby a precursor sol (the sol-gel solution  14 ) of 0.1 mol/L of Pb (Zr 0.53 , Ti 0.47 )O 3  was obtained. 
         [0125]    Here, in order to prevent degradation of crystallinity caused by insufficient lead, lead acetate was added so that an amount of lead was adjusted to exceed 10% mole fraction the amount of lead defined by the stoichiometric composition. 
         [0126]    Next, the silicone wafer, on which the sol-gel solution  14  had been applied, was dried at 120 degrees Celsius, and subsequently the silicone wafer was calcined at 500 degrees Celsius. In this manner, the complex oxide film  14 ′ was formed, and the complex oxide laminated body  15  was formed. At that time, the contact angles of water and methoxyethanol on the area of the common electrode  11 , where the complex oxide film  12  had not been formed, were less than 5 degrees. By these results, it was confirmed that the self-assembled monolayer film  13  did not exist on the area of the common electrode  11 , where the complex oxide film  12  had not been formed. 
         [0127]    Further, the area of the common electrode  11 , where the complex oxide film  12  had not been formed, was analyzed by using an X-ray photoelectron spectroscopic device. 
         [0128]      FIG. 6  shows an analyzing result of an O 1s  peak by an X-ray photoelectron spectroscopy. In  FIG. 6 , (a) is an analyzing result after forming the common electrode  11 , (b) is an analyzing result after calcining the common electrode  11 , (c) is an analyzing result after acid-washing the common electrode  11 , and (d) is an analyzing result after calcining the common electrode  11  five times, without acid-washing. From (a) and (b) of  FIG. 6 , it can be found that, after the common electrode  11  had been calcined, an oxygen content was increased on the area of the common electrode  11 , where the complex oxide film  12  had not been formed. Further, from (b) and (d) of  FIG. 6 , it can be found that an increasing rate of the oxygen content was decreased after calcining the common electrode  11  five times. Therefore, it is considered that there is a saturation state with respect to the oxygen content. Here, the oxygen content was increased because oxygen was adsorbed on the surface of platinum. 
         [0129]    Next, the silicon wafer, on which the complex oxide film laminated body  15  had been formed, was acid-washed by using the self-assembled monolayer film forming apparatus  20  (cf.  FIG. 2 ). Specifically, an acetic acid aqueous solution having a pH of 3.3 was sprayed to the common electrode  11  from the acid nozzle  21   b , and the common electrode  11  was allowed to stand for one minute. Subsequently, the silicon wafer, on which the complex oxide film laminated body  15  had been formed, was washed by spraying it with water from the cleaning solution nozzle  21   c , while removing the acetic acid aqueous solution by rotating the silicone wafer at 500 rpm. Further, water adhering to the silicon wafer, on which the complex oxide film laminated body  15  had been formed, was removed by rotating the silicon wafer at 1500 rpm, without spraying it with water from the cleaning solution nozzle  21   c.    
         [0130]    Here, the pH of the acetic acid aqueous solution was measured at 25 degrees Celsius by the glass electrode. 
         [0131]    Next, the acid-washed silicon wafer was dried by using the self-assembled monolayer film forming apparatus  20  (cf.  FIG. 2 ). Specifically, the silicon wafer, which had been acid-washed, was moved onto the hot plate  23 , and the silicone wafer was dried at 120 degrees Celsius for one minute. At that time, it can be found from (b) and (c) of  FIG. 6  that the oxygen content was decreasing on the area of the common electrode  11 , where the complex oxide film  12  had not been formed. 
         [0132]    Next, similar to the above-described case, the self-assembled monolayer film  13  was formed on the area of the common electrode  11 , where the complex oxide film  12  had not been formed, by using the self-assembled monolayer film forming apparatus  20  (cf.  FIG. 2 ). At that time, the contact angle of water on the area of the common electrode  11 , where the self-assembled monolayer film  13  had been formed but the complex oxide film  12  had not been formed, was 104 degrees both at the center portion and at the periphery. The contact angle of methoxyethanol on the area was 71 degrees both at the center portion and at the periphery. On the other hand, the contact angles of water and methoxyethanol on the other area of the common electrode  11 , where the complex oxide film  12  had been formed, were 5 degrees. 
         [0133]    Next, similar to the above-described case, the sol-gel solution  14  was applied to the area of the common electrode  11 , where the self-assembled monolayer film  13  had not been formed, by using the inkjet device. 
         [0134]    Then, the silicon wafer, to which the sol-gel solution  14  had been applied, was dried at 120 degrees Celsius, and the silicon wafer was calcined at 500 degrees Celsius. In this manner, the complex oxide film  14 ′ having a thickness of 90 nm was additionally laminated. 
         [0135]    Next, similar to the above-described case, the complex oxide film laminated body  15  was acid-washed. Subsequently, the laminating process of laminating the complex oxide film  14 ′ was repeated four times, and thereby forming the complex oxide film laminated body  15  having a thickness of 640 nm. At this time, the silicon wafer, on which the complex oxide film laminated body  15  had been formed, was baked at 700 degrees Celsius by using an infrared rapid thermal annealing (IRTA) apparatus. No cracks were observed. 
         [0136]    Further, similar to the above-described case, the complex oxide film laminated body  15  was acid-washed. Subsequently, the laminating process of laminating the complex oxide film  14 ′ was repeated six times, and thereby forming the complex oxide film laminated body  15  having a thickness of 1180 nm. At this time, the silicone wafer, on which the complex oxide film laminated body  15  had been formed, was baked at 700 degrees Celsius by using the infrared rapid thermal annealing (IRTA) apparatus. No cracks were observed. 
         [0137]    Next, the silicon wafer, on which the complex oxide film laminated body  15  had been formed, was washed by using isopropyl alcohol. Then, by using the sputtering method, a platinum film having a thickness of 200 nm was formed. Further, a pattern of the photo-resist TSMR8800 (produced by Tokyo Ohka Kogyo Co., Ltd.) having a thickness of 1.8 μm was formed. After that, an unnecessary portion of the platinum film was etched by the Ar/O 2  plasma processing, and the photo-resist was removed. In this manner, an electromechanical transducer film was obtained. 
         [0138]      FIG. 7  shows the P-E hysteresis loop of the complex oxide film laminated body  15 . From  FIG. 7 , the complex oxide film laminated body  15  was found to have a dielectric constant of 1220 and a dielectric loss of 0.03. 
       Embodiment 2 
       [0139]    The electromechanical transducer element was obtained by the processes that were the same as those of the Embodiment 1, except that the acetic acid aqueous solution having a pH of 3.8 had been used, instead of the acetic acid aqueous solution having a pH of 3.3. The complex oxide film laminated body  15  was found to have a dielectric constant of 983 and a dielectric loss of 0.02. 
       Embodiment 3 
       [0140]    The electromechanical transducer element was obtained by the processes that were the same as those of the Embodiment 1, except that hydrochloric acid having a pH of 3.3 had been used, instead of the acetic acid aqueous solution having a pH of 3.3. The complex oxide film laminated body  15  was found to have a dielectric constant of 1220 and a dielectric loss of 0.03. 
       Comparative Example 1 
       [0141]    The electromechanical transducer element was obtained by the same processes of the Embodiment 1, except that the acid-washing had not been performed. The form accuracy of the complex oxide film laminated body was degraded. However, the complex oxide film laminated body was found to have a dielectric constant of 1320 and a dielectric loss of 0.02. 
         [0142]    Table 1 shows the evaluation result of the dielectric constant and the dielectric loss of the complex oxide film laminated body according to the embodiment 1-3 and the Comparative example 1. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Embodiment 
                 Embodiment 
                 Embodiment 
                 Comparative 
               
               
                   
                 1 
                 2 
                 3 
                 example 1 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Dielectric 
                 1220 
                 983 
                 1220 
                 1320 
               
               
                 constant 
                   
                   
                   
                   
               
               
                 Dielectric 
                 0.03 
                 0.02 
                 0.03 
                 0.02 
               
               
                 loss 
                   
                   
                   
                   
               
               
                   
               
             
          
         
       
     
         [0143]    From Table 1, it can be found that the dielectric losses of the complex oxide film laminated bodies according to the Embodiments 1-3 are less than 0.04, similar to the case of the complex oxide film laminated body according to the Comparative example 1. The complex oxide film laminated bodies according to the Embodiments 1-3 demonstrate excellent electromechanical transducing characteristics. Further, the complex oxide film laminated bodies according to the Embodiments 1-3 demonstrate the dielectric constants that are similar to the dielectric constant of the complex oxide film laminated body according to the Comparative example 1. 
         [0144]      FIG. 8  shows a relationship between a number of processes for forming the complex oxide films (and thereby forming the complex oxide film laminated body) and a contact angle of water on the area of the common electrode  11 , where the self-assembled monolayer film  13  has been formed, but the complex oxide film  12  has not been formed. 
         [0145]    From  FIG. 8 , it can be found that the contact angle of water on the area of the common electrode  11 , where the self-assembled monolayer  13  has been formed but the complex oxide film  12  has not been formed, is greater than 90 degrees, even if the number of forming the complex oxide films is increased and the number of processes of forming the complex oxide film laminated bodies is increased. Therefore, it can be found that the area of the common electrode  11 , where the self-assembled monolayer film  13  has been formed but the complex oxide film  12  has not been formed, is hydrophobized. 
         [0146]    On the other hand, in the Comparative example 1, the contact angle of water on the area of the common electrode  11 , where the self-assembled monolayer film  13  has been formed but the complex oxide film  12  has not been formed, becomes less than 90 degrees, as the number of forming the complex oxide films is increased and the number of processes of forming the complex oxide film laminated bodies is increased. Therefore, it can be found that the area of the common electrode  11 , where the self-assembled monolayer film  13  has been formed but the complex oxide film  12  has not been formed, is not hydrophobized. 
         [0147]    In the above description, the method of manufacturing electromechanical transducer element has been explained by the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and improvements may be made within the scope of the present invention. 
         [0148]    The present application is based on Japanese Priority Applications No. 2011-202821 filed on Sep. 16, 2011, and No. 2012-000950 filed on Jan. 6, 2012, the entire contents of which are hereby incorporated herein by reference.