JP4282079B2 - Piezoelectric element and liquid discharge head including the element - Google Patents

Description

  The present invention relates to a piezoelectric (electrostrictive) element and a liquid discharge head (hereinafter also referred to as “inkjet head”) including the element. In particular, the present invention relates to a piezoelectric element that can be applied as a sensor, a transducer, an actuator, or the like. In particular, it is suitable for MEMS elements and inkjet heads that have attracted attention in recent years. In addition to inkjet heads, it is applied to memory heads, optical shutters, ultrasonic motors, speakers, and the like.

  In recent years, a piezoelectric element in which an element is fabricated on a Si substrate has been developed in consideration of use of a semiconductor process. Therefore, studies on thin film forming methods such as a sol-gel method, a sputtering method, and an MO-CVD method have been made. Further, in order to improve the characteristics of the piezoelectric element, studies for improving the crystallinity of the piezoelectric film have been made together.

  In particular, it has been announced that a piezoelectric film such as PZT is made to have (001) preferred orientation or (111) preferred orientation using a general-purpose Si substrate having a (100) surface.

  In addition, a (110) preferentially oriented film has been studied as a piezoelectric film, but a high-temperature process of 700 ° C. or higher is required to form a piezoelectric film on a Si substrate with crystal control.

For example, those described in Patent Documents 1 and 2 are known as those using a (110) preferentially oriented piezoelectric film.
JP 2001-80995 A JP 2003-179279 A

  The piezoelectric element described in Patent Document 1 uses a Si substrate having a (110) surface, and is a method of stacking (110) preferential orientation on a (110) surface. Is required. For this reason, stress remains in the film, causing a problem in durability.

  In the piezoelectric element described in Patent Document 2, a (100) preferentially oriented buffer layer (such as YSZ) is formed on a Si substrate having a (100) surface, and then the crystal control is performed on the electrode layer at (110). However, similarly, a high-temperature process is required for forming the buffer layer, and the same problem as that of the piezoelectric element described in Patent Document 1 occurs. In particular, when a buffer layer is used as a diaphragm in an ink jet head, problems such as cracking of the diaphragm and peeling between the electrode layer and the buffer layer may occur due to the influence of residual stress.

  One of the objects of the present invention is a piezoelectric element including a piezoelectric layer and a pair of electrode layers sandwiching the piezoelectric layer, and is preferentially oriented on the (100) plane of Si and on the (110) plane. The piezoelectric element is characterized in that at least three layers are laminated, and the at least three layers include the piezoelectric layer and one of the pair of electrode layers.

  The present invention also provides a (110) preferentially oriented, uniaxially oriented piezoelectric layer or (110) epitaxial layer piezoelectric layer on a Si substrate having a (100) surface.

The present invention also relates to a piezoelectric element obtained therefrom and a liquid discharge head provided with this piezoelectric element.
In particular, in the present invention, it is possible to obtain a piezoelectric element and an ink jet head having good characteristics in which the film forming temperature can be set to a low temperature and the stress in the film is reduced.

  Since the piezoelectric element of the present invention has at least three or more layers oriented preferentially on the (110) plane on the (100) surface of the Si substrate, the film forming temperature can be set to a low temperature, which depends on the influence of residual stress, etc. It is possible to obtain a piezoelectric element that is free from cracks in the diaphragm and peeling between the electrode layer and the buffer layer. Further, in the present invention, it is possible to obtain a piezoelectric element and an ink jet head having good characteristics with reduced stress in the film.

  The piezoelectric element of the present invention will be described. The present invention relates to a piezoelectric element having at least three (110) preferentially oriented functional layers on a (100) surface of a Si substrate. The functional layer is a piezoelectric element that can be a buffer layer, an electrode layer, and a piezoelectric layer. The three functional layers are at least one of the piezoelectric layer and the pair of electrode layers. It functions as (upper electrode layer or lower electrode layer). In particular, there is no difference in orientation between the buffer layer and the electrode, and the device is excellent in durability without problems such as electrode peeling.

  In the present invention, “preferential orientation” means a (110) plane preferentially oriented substantially parallel to the substrate surface, an in-plane random uniaxial orientation, or an epitaxial orientation in which the in-plane orientation is also oriented. The orientation is measured by an X-ray diffraction method.

  In addition, the piezoelectric element of the present invention includes at least a (110) preferentially oriented fluorite-type oxide layer, a (110) preferentially oriented electrode layer, and a (110) preferentially oriented piezoelectric material on the (100) surface of the Si substrate. A piezoelectric element having a body layer is preferred.

  In particular, the layer serving as the buffer layer is preferably a fluorite oxide. The electrode layer preferably has two or more layers, and at least one of the layers is a piezoelectric element that is a perovskite oxide conductive layer.

  The piezoelectric layer may preferably include a pseudo cubic crystal structure. Alternatively, it may include at least two kinds of crystal structures selected from the group consisting of pseudo-cubic crystals, rhombohedral crystals, and tetragonal crystals.

The piezoelectric layer preferably contains an ABO ₃ type perovskite oxide. The piezoelectric layer of the present invention means a piezoelectric film and / or an electrostrictive film. Examples of the material used for the piezoelectric film include perovskite compounds. For example, an electrostrictive material of the piezoelectric material and a relaxor material such as lead zirconate titanate _{PZT [Pb (Zr x Ti 1} -x) O 3] or barium titanate BaTiO _3. MP of lead zirconate titanate (PZT) is preferably MP5 (morphotropic phase boundary) composition of 0.45 to 0.65, but other composition ratios may be used.

The following can be selected as the electrostrictive material used in the present invention. For _{example, PMN [Pb (Mg x Nb} 1-x) O 3], PNN [Pb (Nb x Ni 1-x) O 3], PSN [Pb (Sc x Nb 1-x) O 3], PZN [Pb _{(Zn x Nb 1-x)} O 3], PMN-PT {(1-y) [Pb (Mg x Nb 1-x) O 3] -y [PbTiO 3]}, PSN-PT {(1-y _{) [Pb (Sc x Nb 1} -x) O 3] -y [PbTiO 3]}, PZN-PT {(1-y) [Pb (Zn x Nb 1-x) O 3] -y [PbTiO 3] }, LN [LiNbO ₃ ], KN [KNbO ₃ ]. Here, x and y are numbers of 1 or less and 0 or more. For example, in the case of PMN, x is 0.2 to 0.5, and in PSN, x is preferably 0.4 to 0.7, y of PMN-PT is 0.2 to 0.4, and y of PSN-PT is 0.35-0.5, y of PZN-PT is preferably 0.03-0.35. Further, PMN-PZT, PZN-PZT, and PSN-PZT compounds in which Zr is substituted for Ti in PMN-PT, PZN-PT, and PSN-PT may be used. Preferably, Zr is not included so as not to lower the Curie temperature.

  The piezoelectric film may have a single composition or a combination of two or more. Moreover, the composition which doped the trace amount element to the said main component may be sufficient. The piezoelectric / electrostrictive film of the present invention is preferably crystal-controlled in order to exhibit excellent piezoelectricity, and preferably has a (110) orientation of the crystal structure of 50% or more by X-ray diffraction, 90% or more is more preferable.

  With the above configuration, a (110) preferentially oriented piezoelectric layer with good orientation can be obtained. In addition to the Si substrate having a (100) surface (Si substrate having a (100) plane), the substrate of the present invention preferably has a (100) plane Si layer / oxide layer / The substrate has a Si layer with a (110) plane (the functional layer is provided on the Si layer with a (100) plane).

  The present invention also relates to an ink jet head having the piezoelectric element. The method for manufacturing a piezoelectric element according to the present invention includes a step of forming a (110) preferentially oriented fluorite-type oxide layer on the (100) surface of a Si substrate, and (110) a preferentially orienting electrode layer. The manufacturing method which has the process of forming and the process of forming the piezoelectric material layer of (110) priority orientation can be mentioned.

  In particular, in the step of forming the fluorite-type oxide layer as the buffer layer, the substrate temperature can be 100 ° C. or higher and 400 ° C. or lower. As a result, a (110) preferentially oriented film can be obtained, and an element having a low stress in the film and free from problems such as peeling can be obtained. In addition, the present invention is preferably a manufacturing method using a Si layer having a (100) plane orientation / oxide layer / Si layer having a (110) plane orientation as a substrate. Here, the Si layer having a plane orientation of (110) may be a part that is processed as a piezoelectric element upon device formation.

Next, the piezoelectric element will be described in detail. There are at least three (110) preferential alignment layers, which are functional layers as the piezoelectric element of the present invention, and include a piezoelectric layer and one electrode layer. The three layers preferably include a buffer layer. The electrode layer included in the three layers ((110) preferential orientation layer) may be a lower electrode or an upper electrode. The functional layers are stacked in the order of the buffer layer, the lower electrode layer, and the piezoelectric layer from the substrate (Si layer on the (100) surface) side. The order is the body layer, the upper electrode layer, and the buffer layer. Preferred thicknesses of this functional layer are 0.01 μm to 0.5 μm for the buffer layer, 0.5 μm to 15 μm for the piezoelectric layer, and 0.1 μm to 0.5 μm for the electrode layer. The buffer layer is preferably a layer containing a fluorite-type oxide. The fluorite type oxide, for _{example, AmO 2, CeO 2, CmO} 2, K 2 O, Li 2 O, Na 2 O, NpO 2, PaO 2, PuO 2, RbO 2, TbO 2, ThO 2, UO ₂ and ZrO ₂ , preferably CeO ₂ and ZrO ₂ , and (110) preferred orientation. ZrO ₂ may contain a rare earth element as a dopant. By selecting a fluorite type oxide, a (110) preferentially oriented film can be obtained on the (100) surface of the Si substrate by low-temperature film formation at 500 ° C. or lower, preferably 400 ° C. or lower.

  The electrode layer preferably has a two-layer structure, and at least one of them is preferably a perovskite oxide conductive layer. The oxide conductive layer is preferably disposed on the piezoelectric layer side. In addition to the oxide, the electrode material used is a metal material, which can be a face-centered cubic crystal, a body-centered cubic crystal, or a six-method close-packed structure material. A face-centered cubic crystal is preferable.

  Examples of the metal material to be face-centered cubic include Ni, Pt, Pb, Ir, Cu, Al, Ag, and γ-Fe. Pt and Ir are preferable. This metal layer can be used when forming a device as an etch stop layer for etching or the like.

In order to improve the crystallinity of the piezoelectric layer, the perovskite oxide conductive layer of the electrode layer is composed of (Sr _x , Ca _y , Ba _z ) RuO ₃ (where x + y + z = 1) oxide, and La is an A site. It is preferable to contain a perovskite oxide present in

Examples of the oxide in which La enters the A site include LaMoO ₃ , LaCoO ₃ , LaCrO ₃ , LaAlO ₃ , LaSrCoO ₃ , LaCuO ₃ , LaSrMnO ₃ , CaLaMnO ₃ , LaCaRhO ₃ , LaSrRhO ₃ h, LaSrRhO ₃ h, LaSrRhO ₃ , LaB Is mentioned.

The composition of these perovskite compounds, including the piezoelectric layer, is indicated as ABO ₃ , but the composition does not have to be completely 1: 1: 3, and the present invention can be applied to a case where the composition does not deteriorate the characteristics. It is a range. For example, oxygen in the perovskite oxide conductive layer may be oxygen-poor as long as it does not cause significant problems in conductivity and crystallinity, and the A-site element is rich in order to improve the characteristics of the piezoelectric layer. May be. The range of composition deviation is not particularly limited, but for example, a phenomenon that deviates within a range of ± 10% is an allowable range although it depends on the manufacturing method.

  In the present invention, the case where the functional layer has (110) preferential orientation is shown. However, when the crystal structure is tetragonal, a part of the functional layer includes (101) preferential orientation and (011) preferential orientation. . In particular, a fluorite-type oxide has a cubic crystal structure, but may have a tetragonal structure with an extended c-axis under film formation conditions in sputter film formation.

  The present invention relates to an ink jet head characterized by having the piezoelectric element. Since the ink jet head of the present invention has the piezoelectric element, the head has good durability and stable performance. The ink jet head of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram of an ink jet head, where 1 is a discharge port, 2 is a communication hole connecting the individual liquid chamber 3 and the discharge port 1, 4 is a common liquid chamber, 5 is a diaphragm, 6 is a lower electrode, and 7 is a piezoelectric. The body layer 8 is an upper electrode. The piezoelectric film 7 has a rectangular shape as shown in the figure. This shape may be an ellipse, a circle, a parallelogram, etc. in addition to a rectangle. The piezoelectric film 7 of the present invention will be described in more detail with reference to FIG. FIG. 2 is a cross-sectional view in the width direction of the piezoelectric film of FIG. In the figure, 11 is a substrate, and 5 is a Si layer having a (100) surface. Reference numeral 6 denotes a (110) preferentially oriented buffer layer. 9 is a (110) preferentially oriented lower electrode layer, 7 is a (110) preferentially oriented piezoelectric layer, and 8 is an upper electrode layer.

  In the inkjet head, 5 and 6 function as diaphragms. Although the electrode 9 is patterned and displayed in the same manner as the piezoelectric layer, it may be a uniform solid film as in the buffer layer. On the contrary, the buffer layer 6 may have a structure patterned similarly to the electrode layer. The electrode layer 9 preferably has a two-layer structure, and preferably has a perovskite oxide conductive layer on the piezoelectric layer side and a metal layer on the buffer layer side. In that case, the metal layer is preferably a solid film that is not patterned, and the oxide layer is preferably patterned similarly to the piezoelectric layer. Although the cross-sectional shape of 7 is displayed as a rectangle, it may be a trapezoid or an inverted trapezoid. The configuration order of 8, 9, and 6 may be reversed upside down. That is, the upper electrode 9 may be formed on the piezoelectric film in the order of 7 (piezoelectric film) / 9 (electrode layer) / 6 (buffer layer). In this case, the element may not have six buffer layers. The reason why the configuration is reversed in this way is due to the device manufacturing method, and even when the configuration is reversed, the effect of the present invention can be obtained in the same manner.

  The electrode layer 9 serving as the lower electrode is drawn to a portion where the piezoelectric film 7 does not exist, and the upper electrode 8 is drawn to the side (not shown) opposite to the lower electrode and connected to a driving power source.

Preferred layer configurations of the electrode layer / buffer layer / Si substrate of the piezoelectric element of the present invention are exemplified below. () Represents the preferred orientation of the crystal. Each layer is provided on the (100) surface of the Si substrate.
(1) SrRuO ₃ (110) / Pt (110) / CeO ₂ (110) / Si
(2) SrRuO ₃ (110) / Ir (110) / CeO ₂ (110) / YSZ (110) / Si
(3) CaRuO ₃ (110) / Pt (110) / CeO ₂ (110) / Si
(4) LaNiO ₃ (110) / Ir (110) / CeO ₂ (110) / Si
(5) CaRuO ₃ (110) / Ir (110) / CeO ₂ (110) / ZrO ₂ (110) / Si
(6) LaSrCoO ₃ (110) / Ru (110) / CeO ₂ (110) / Si
(7) LaSrCoO ₃ (110) / Pt (110) / CeO ₂ (110) / Si
(8) SrRuO ₃ (100) / CeO ₂ (110) / YSZ (110) / Si
Among the above configurations, particularly preferable configurations are (1), (2), and (7). As a diaphragm material in the ink jet head of the present invention, a Si layer having a (100) plane orientation is used. A laminate of this and a buffer layer, or a laminate of this, a buffer layer and an electrode layer is used as a diaphragm. May be.

  The thickness of the diaphragm 5 in the inkjet head of the present invention is 0.5 to 10 μm, preferably 1.0 to 6.0 μm. Moreover, the film thickness of an electrode layer is 0.05-0.65 micrometer, Preferably, it is 0.08-0.4 micrometer. The film thickness of the buffer layer is 5 nm to 450 nm, preferably 10 nm to 200 nm. By setting the film thickness, the crystallinity can be maintained well, and the crystallinity of the piezoelectric layer can be improved. The film thickness of the (110) preferentially oriented electrode layer is 50 nm to 650 nm, preferably 80 nm to 400 nm.

  FIG. 3 is a plan view of the individual liquid chamber of the ink jet head as viewed from the piezoelectric layer side. The width Wa of the individual liquid chamber 12 is 30 to 180 μm. The length Wb (see FIG. 3) is 0.3 to 6.0 mm, although it depends on the discharged droplet amount. The shape of the discharge port 1 on the opposite surface is circular or star-shaped, and the diameter is preferably 7 to 40 μm. It is preferable that the cross-sectional shape of the discharge port has a tapered shape expanded in the direction of the communication hole 2. The length of the communication hole 2 is preferably 0.05 mm to 0.5 mm. If the length exceeds 0.5 mm, the droplet discharge speed may be reduced. Further, if it is less than 0.05 mm, there is a fear that the variation in the ejection speed of the droplets ejected from each ejection port becomes large.

  7 and 8 are schematic views of an ink jet recording apparatus using the ink jet head of the present invention. Accordingly, the present invention can achieve an ink jet recording apparatus with stable ejection characteristics, a long-life ink jet head, and good performance. FIG. 8 shows the operation mechanism part with the exterior of FIG. 7 removed. An automatic feeding unit 97 that automatically feeds recording paper as a recording medium into the apparatus main body, and a recording paper sent from the automatic feeding unit 97 is guided to a predetermined recording position, and from the recording position to the discharge port 98. And a transport unit 99 that guides the recording paper, a recording unit that records on the recording paper transported to the recording position, and a recovery unit 90 that performs recovery processing on the recording unit. The ink jet head of the present invention is disposed and used on a carriage 92. Although FIG. 7 shows an example of a printer, the present invention may be used for a fax machine, a multifunction machine, a copier, or an industrial discharge apparatus.

  The method for manufacturing a piezoelectric element according to the present invention is a method for providing a (110) preferentially oriented electrode layer and piezoelectric layer on the (100) surface of a Si substrate. As an example of this manufacturing method, a step of forming a (110) preferentially oriented fluorite-type oxide layer (buffer layer) on a substrate, and a (110) preferentially-oriented electrode layer on a fluorite-type oxide layer There is a manufacturing method including a step of forming a (110) preferentially oriented piezoelectric layer on an electrode layer. In particular, the substrate temperature when forming the fluorite-type oxide layer is 100 ° C. or higher and 400 ° C. or lower, preferably 100 ° C. or higher and 350 ° C. or lower.

  As a result, the (110) crystal controllability of the buffer layer is improved, and the characteristics after the piezoelectric element is formed can be maintained well.

Furthermore, another example of this manufacturing method is a manufacturing method using a substrate having a configuration of a Si layer having a (100) plane orientation / an oxide layer / a Si layer having a (110) plane orientation. Since the Si layer having the (100) plane orientation or the Si layer and the oxide layer having the (100) plane orientation are used for the above-described diaphragm (for example, the vibration plate 5 in FIGS. 1 and 2), the above-described diaphragm is used. Use a film thickness. However, when the oxide layer does not become a diaphragm on the individual liquid chamber by the processing method and is removed by etching or the like, the Si layer is used as the diaphragm. The oxide layer is a SiO ₂ layer or a B ₂ O ₃ —SiO ₂ layer, but other oxides may be used.

  An individual liquid chamber suitable for an inkjet head can be provided by processing the Si layer having the (110) plane orientation of the substrate by wet etching.

  As another aspect of the manufacturing method of the present invention, there is a method in which the (110) preferentially oriented layer of the present invention is formed on a (100) plane Si substrate and this is transferred to a structure having a diaphragm. is there. Further, a method of forming a (110) preferentially oriented layer of the present invention, forming an electrode layer and a vibration plate, and transferring to another substrate or a substrate on which an individual liquid chamber or the like is processed may be used.

  As the substrate in this case, a substrate with random crystallinity such as SUS, Inconel, Ti foil, or Ni foil can be used in addition to the Si substrate.

  As a method of manufacturing the ink jet head of the present invention, even if the method of forming an individual liquid chamber serving as a pressure chamber in the substrate on which the piezoelectric layer is formed, another liquid chamber is separately formed or can be formed. A method of transferring a component to be a piezoelectric element to the substrate may be used.

  The electrode layer and dielectric layer (piezoelectric layer) can be formed by sputtering, MO-CVD, laser ablation, sol-gel, MBE, etc., preferably sputtering, MO-CVD, sol-gel. More preferably, the MO-CVD method and the sputtering method are used. As a condition other than the substrate temperature by the MO-CVD method, it is preferable to adopt the pulse MO-CVD method in which the source gas is not supplied continuously but intermittently supplied onto the substrate.

  The inkjet head manufacturing method of the present invention employs a method of providing an individual liquid chamber serving as a pressure chamber on a substrate used when the dielectric is formed, and two methods of providing an individual liquid chamber on another substrate. .

  The former method is the same as the above-described manufacturing method until the step of providing the piezoelectric layer, and further includes at least a step of removing a part of the substrate and a step of forming an ink discharge port. By removing a part of the substrate, an individual liquid chamber (3 in FIG. 1 or 12 in FIG. 2) is formed. The manufacturing method of the individual liquid chamber can be manufactured by wet etching, dry etching, or sand mill of the substrate. As described above, the wet etching process is applied to the Si layer having the (110) plane orientation as described above. Preferably it is done. A plurality of individual liquid chambers are formed on the substrate at a fixed number of pitches. As shown in FIG. 4 illustrating the planar arrangement of the inkjet head, it is preferable that the individual liquid chambers 12 are arranged in a staggered arrangement. In FIG. 4, 12 regions indicated by broken lines are individual liquid chambers to which pressure is applied, and 7 is a patterned piezoelectric element portion. The piezoelectric film of the piezoelectric element portion is composed of at least the dielectric layer of the present invention and the upper electrode. Reference numeral 5 denotes a diaphragm portion and a lower electrode. Unlike the diaphragm, the lower electrode may be patterned as shown in FIG. In FIG. 4, the shape of the individual liquid chambers is shown as a parallelogram. A Si substrate having a (110) plane orientation is used as the substrate, and the individual liquid chambers are formed by performing wet etching with an alkali etchant. This is because such a shape is obtained. In addition to this, the shape of the individual liquid chamber may be rectangular or square. In the case of the parallelogram shape shown in FIG. 4, it is preferable that the piezoelectric film is also patterned into a parallelogram shape in order to shorten the distance between the discharge ports 1 and 1 '.

The ink discharge port is formed by a method of bonding a substrate on which the discharge port 1 is provided, or a method of bonding a substrate on which the discharge port 1 and the communication hole 2 are formed. FIG. 9 shows an outline of the ink discharge ports formed in this way. The discharge port is formed by etching, machining, or laser light irradiation. The substrate on which the discharge ports are formed may be the same as or different from the substrate on which the piezoelectric film is formed. Substrates selected for different cases include SUS substrates, Ni substrates, etc., and materials having a difference in thermal expansion coefficient from the substrate on which the piezoelectric film is formed from 10 ⁻⁶ / ° C. to 10 ⁻⁸ / ° C. are selected. Is done.

  As a method for bonding the substrates, a method using an organic adhesive may be used, but a method using metal bonding with an inorganic material is preferable. Materials used for metal bonding are In, Au, Cu, Ni, Pb, Ti, Cr, Pd, etc., which can be bonded at a low temperature of 300 ° C. or less, and the difference in thermal expansion coefficient from the substrate is small. In addition to avoiding problems due to warping of elements when scaled, there is no damage to the piezoelectric layer, which is preferable.

  Next, the second manufacturing method will be described. The second method is a method of transferring a piezoelectric layer provided on the first substrate to the second substrate. The method is the same as that described above until the piezoelectric layer is provided, but the diaphragm 5 is formed on the upper electrode without patterning the piezoelectric layer, and transferred to the second substrate.

Alternatively, an electrode and / or a diaphragm is formed on the piezoelectric layer, the diaphragm is bonded to the second substrate, and the transfer is performed including the piezoelectric layer. Alternatively, as described above, the piezoelectric layer is patterned and transferred to the second substrate provided with the vibration plate. In the second substrate, for example, the individual liquid chamber 12, the communication hole 2, and the common liquid chamber 4 are sequentially formed by the steps a) to f) shown in FIG.
a) a step of forming a mask 11a corresponding to the individual liquid chamber on the second substrate 11;
The step b) is a step in which the mask 11a provided in the step a) is used as an etching mask and processing is performed from above by etching or the like to provide the individual liquid chamber 12 (the hatched portion 12a means a processing portion (individual liquid chamber)). ,
c) The step is a step of creating a mask 11b for the communication hole 2 on the opposite side of the mask provided in the mask removal step and the second substrate a) step,
Step d) is a step of forming the communication hole 2 and the common liquid chamber 4 by processing the hatched portions 2a and 4a by etching or the like using the mask 11b provided in the step c) as an etching mask.
Step e) schematically shows a state in which the individual liquid chamber 12, the communication hole 2, and the common liquid chamber 4 are formed by removing the mask formed in step c).
Step f) shows a state where the discharge port 1 and the substrate on which a part of the common liquid chamber is formed are joined.

  FIG. 6 further shows the Si layer 5 having the (100) plane, the lower electrode 9, and the piezoelectric layer 7 on the individual liquid chamber side, although the discharge port and the common liquid chamber are joined in the step f) of FIG. 2 shows an ink jet head in which three functional layers of the upper electrode 8 are joined. It is preferable that the substrate surface 16 (FIG. 6) having the discharge port of the ink jet head of FIG. 6 is subjected to water repellent treatment.

  In addition, as described as an example of the latter method, a piezoelectric body is formed when a diaphragm is formed on a second substrate, a piezoelectric layer is transferred onto the second substrate, and the first substrate is removed. The patterned state may or may not be. When this step is employed, it is preferable to use the metal bonding layer as the lower electrode.

  The manufacturing method for manufacturing the ink jet head of the present invention includes the piezoelectric layer patterning and / or the first substrate removal step during the manufacturing process. In this case, if there is a metal electrode film, the etching stop is performed. It can be used as a layer and is preferable in terms of the process.

  Further, the stress of the fluorite-type oxide layer of the buffer layer can be controlled to cope with it, and problems such as cracking, peeling and warping can be eliminated. Next, the present invention will be described with reference to examples.

Examples are shown below. In the examples, () represents the preferential orientation of the crystal.

(Example 1)
First, a (100) plane Si layer is formed with a thickness of 3 μm, a B ₂ O ₃ —SiO ₂ layer is 2 μm as an oxide layer, and a (110) plane Si layer is 625 μm as a handle substrate. A substrate having the following structure was prepared. A CeO ₂ layer (buffer layer) having a thickness of 50 nm was formed on the Si layer having the (100) plane orientation of the substrate by sputtering at a substrate temperature of 250 ° C., a gas pressure of 0.5 Pa. The CeO ₂ layer had good (110) preferred orientation. On top of this, Pt (110) (lower electrode layer) and a SRO (110) film (lower electrode layer: strontium ruthenate) were provided with a thickness of 30 nm and 150 nm, respectively, at a substrate temperature of 450 ° C. Further, a piezoelectric layer was formed to a thickness of 3.5 μm at a substrate temperature of 550 ° C. with a composition ratio of Pb (Zr _0.60 Ti _0.40 ) O ₃ . This piezoelectric layer had a (110) preferential orientation of 95% or more and a mixture of tetragonal crystals and rhombohedral crystals.

  Then, after depositing 120 nm of SRO as the upper electrode, the Si substrate portion having a (110) plane orientation is etched to remove the parallelogram portion having a width of 60 μm and a length of 2.2 mm, thereby providing a plurality of pressure chambers. Was formed at a density of 300 dpi, and the upper electrode and the piezoelectric layer were patterned corresponding to the pressure chamber. The ink jet head 1 having the piezoelectric element of the present invention was obtained by joining an orifice plate having a communicating portion for communicating the nozzle and each pressure chamber.

(Example 2)
After the Si layer surface having the (100) plane orientation of the substrate used in Example 1 was treated with hydrofluoric acid, a ZrO ₂ layer (buffer layer) doped with Y was formed by sputtering at a substrate temperature of 300 ° C. and a thickness of 100 nm. Then, a CeO ₂ layer (buffer layer) was formed to a thickness of 60 nm at a substrate temperature of 350 ° C. Both were (110) preferentially oriented films. On this, a laminated structure of SRO / Ir was formed as a lower electrode layer at substrate temperatures of 400 ° C. (Ir) and 450 ° C. (SRO), respectively. Both were (110) preferentially oriented films. A PZT film (Zr / Ti ratio = 62/38) (piezoelectric film) was formed thereon by sputtering at a substrate temperature of 550 ° C. to a thickness of 3.5 μm. The orientation of the piezoelectric film was a (110) preferential orientation film with an orientation ratio of 92% and a mixed system of tetragonal crystals and rhombohedral crystals. Thereafter, the inkjet head 2 was obtained by processing in the same manner as in Example 1.

(Example 3)
Using an SOI substrate having a Si (100) first layer / SiO ₂ layer / Si (100) second layer structure (each having a thickness of 3 μm / 1 μm / 300 μm), a CeO film is formed on the 3 μm thick Si (100) first layer. ₂ (110) (buffer layer) was formed by sputtering at a substrate heating temperature of 400 ° C. to a thickness of 40 nm. On top of this, Pt (110) is 120 nm thick as a lower electrode layer, (La, Sr) CoO ₃ (110) is 40 nm, and (110) Pb (Zr _0.55 , Ti _0.45 ) O ₃ is ( ₃ ) as a piezoelectric layer. The film was formed at a thickness of 5 μm at 600 ° C. A gold upper electrode layer was patterned on this, and a PZT film was patterned along the upper electrode layer with a width of 47 μm and a length of 3 mm. The Si second layer side was etched away to the SiO ₂ layer by the ICP method so as to match the portion where PZT remained, and a plurality of individual liquid chambers 3 having a width of 58 μm and a length of 2.6 mm were formed.

  An SUS substrate provided with a communication hole, a discharge port, and an ink supply path was joined to this element to obtain an inkjet head 3 of the present invention. Moreover, the inkjet head 4 which expanded the width | variety of the separate liquid chamber to 90 micrometers by the method similar to the above was obtained.

(Evaluation)
The head was applied with an electric field strength of 10,000 kV / m, and a liquid having a viscosity of 3.5 cps was ejected to evaluate the characteristics. The results are shown in Table 1. The droplet amount and the discharge speed here were converted from the droplet size and the moving distance by a high-speed camera. All of the above heads were excellent in durability, and it was confirmed that there was no significant deterioration in characteristics even after ejection of 108 times or more as compared with the initial ejection.

Schematic of ink jet head according to the present invention Sectional view of a piezoelectric element according to the present invention The top view of the separate liquid chamber of the ink jet head concerning the present invention Plan view of an inkjet head according to the present invention Schematic which shows the 2nd board | substrate manufacturing process of the inkjet head which concerns on this invention. Sectional drawing of the longitudinal direction of the inkjet head which concerns on this invention Overview of inkjet recording apparatus according to the present invention Schematic of an ink jet recording apparatus excluding an exterior according to the present invention Schematic of the liquid ejection part of the inkjet according to the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid discharge port 2 Communication hole 3 Individual liquid chamber 4 Common liquid chamber 5 Si (100) layer 7 Piezoelectric layer 8 Upper electrode 10 Oxide layer 11 Substrate 12 Individual liquid chamber 13 Upper electrode

Claims (10)

A piezoelectric element including a piezoelectric layer and a pair of electrode layers sandwiching the piezoelectric layer,
At least three layers preferentially oriented in the (110) plane are stacked on the (100) plane of Si, and the at least three layers include the piezoelectric layer and one of the pair of electrode layers. A piezoelectric element characterized by the above.   The piezoelectric element according to claim 1, wherein the at least three layers have a buffer layer.   2. The piezoelectric element according to claim 1, wherein the at least three layers include a fluorite-type oxide layer.   The piezoelectric element according to claim 1, wherein the piezoelectric layer has a pseudo-cubic crystal structure.   4. The piezoelectric according to claim 1, wherein the piezoelectric layer has at least two kinds of crystal structures selected from the group consisting of pseudo-cubic crystals, rhombohedral crystals, and tetragonal crystals. 5. Body element. The piezoelectric element according to claim 3, wherein the fluorite-type oxide layer contains at least one of CeO ₂ and ZrO ₂ .   4. The piezoelectric element according to claim 3, wherein the fluorite-type oxide layer is formed by heat-treating a material of the fluorite-type oxide layer at 100 ° C. or more and 400 ° C. or less. .   8. The piezoelectric element according to claim 1, wherein one of the pair of electrode layers preferentially oriented in the (110) plane has a perovskite oxide conductive layer.   The layer having the (100) plane of Si is provided in contact with an oxide layer provided in contact with the Si layer having a plane orientation of (110). The piezoelectric element according to item 1. A piezoelectric element including a piezoelectric layer and a pair of electrode layers sandwiching the piezoelectric layer, and a pressure chamber member provided with a pressure chamber corresponding to the piezoelectric element. A liquid discharge head for discharging liquid in the pressure chamber by displacement,
In the piezoelectric element, at least three layers preferentially oriented in the (110) plane are stacked on the (100) plane of Si, and the at least three layers are formed of the piezoelectric layer and the pair of electrode layers. A liquid ejection head comprising: one layer.

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