Piezoelectric device, liquid ejection head, liquid ejection apparatus, and method for manufacturing piezoelectric device

Abstract

To provide a piezoelectric device, a liquid injection head, a liquid injection device, and a method for manufacturing piezoelectric device, capable of suppressing the breakage of a diaphragm.SOLUTION: A liquid injection head 2 includes a substrate 10, a diaphragm 50, and a piezoelectric actuator 300, the substrate, the diaphragm, and the piezoelectric actuator being stacked in a first direction Z in this order. The diaphragm has: a first layer 51 containing silicon as constituent elements; a third layer 53 arranged between the first layer and the piezoelectric actuator and containing zirconium as constituent elements; and a second layer 52 arranged between the first layer and the third layer and containing, as constituent elements, at least one selected from the group consisting of a metal other than iron, silicon and zirconium, a metalloid, and a semiconductor. In the diaphragm, a position with the highest concentration of impurities other than the constituent elements of the second layer and the third layer is in the second layer, a position with the highest concentration of zirconium is in the third layer, and a position with the highest concentration of silicon is in the first layer.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a piezoelectric device having a vibration plate and a piezoelectric actuator provided on a substrate, a liquid ejection head that ejects liquid, a liquid ejection apparatus, and a method for manufacturing a piezoelectric device. [Background technology]

[0002] Inkjet recording heads are known as liquid ejection heads, which are one type of electronic device. The inkjet recording head includes a substrate provided with pressure chambers communicating with nozzles, a vibration plate provided on one side of the substrate, and a piezoelectric actuator provided on the vibration plate. The piezoelectric actuator is driven to cause a pressure change in the ink in the pressure chambers, causing ink droplets to be ejected from the nozzles. For example, Patent Document 1 discloses a vibration plate having an elastic film made of silicon dioxide and an insulating film made of zirconium oxide. Here, the elastic film is formed by thermally oxidizing one side of a silicon single crystal substrate. The insulating film is formed by thermally oxidizing a layer of simple zirconium formed on the elastic film by a sputtering method or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-78407 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a problem that when an external force is applied due to deformation of the piezoelectric actuator, the diaphragm can be damaged, such as by delamination or cracking. [Means for solving the problem]

[0005] An aspect of the present invention that solves the above problem is a piezoelectric device comprising a substrate, a vibration plate, and a piezoelectric actuator, the substrate, the vibration plate, and the piezoelectric actuator being stacked in this order in a first direction, the vibration plate having a first layer containing silicon as a constituent element, a third layer disposed between the first layer and the piezoelectric actuator and containing zirconium as a constituent element, and a second layer disposed between the first layer and the third layer and containing at least one element selected from the group consisting of iron, metals other than silicon and zirconium, semi-metals, and semiconductors, the second layer and the third layer having the highest concentration of impurities other than the constituent elements of the second layer and the third layer being located in the second layer, the third layer having the highest zirconium concentration being located in the third layer, and the first layer having the highest silicon concentration.

[0006] Another aspect of the present invention is a liquid ejection head comprising: a piezoelectric actuator; a vibration plate that vibrates when driven by the piezoelectric actuator; and a flow path forming substrate provided with a pressure chamber that applies pressure to a liquid by vibration of the vibration plate, wherein the flow path forming substrate, the vibration plate, and the piezoelectric actuator are stacked in this order in a first direction, the vibration plate having a first layer containing silicon as a constituent element, a third layer that is disposed between the first layer and the piezoelectric actuator and contains zirconium as a constituent element, and a second layer that is disposed between the first layer and the third layer and contains at least one element selected from the group consisting of iron, metals other than silicon and zirconium, semi-metals, and semiconductors, wherein in the second layer and the third layer, a position where impurities other than the constituent elements of the second layer and the third layer are highest is located in the second layer, a position where zirconium concentration is highest is located in the third layer, and a position where silicon concentration is highest is located in the first layer.

[0007] Another aspect of the present invention is a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.

[0008] Yet another aspect of the present invention is a piezoelectric actuator comprising a substrate, a vibration plate, and a piezoelectric actuator, the substrate, the vibration plate, and the piezoelectric actuator being laminated in this order in a first direction, the vibration plate having a first layer containing silicon as a constituent element, a third layer disposed between the first layer and the piezoelectric actuator and containing zirconium as a constituent element, and a second layer disposed between the first layer and the third layer and containing at least one element selected from the group consisting of iron, metals other than silicon and zirconium, semi-metals, and semiconductors, the second layer and the third layer having the highest concentration of impurities other than the constituent elements of the second layer and the third layer being at a position corresponding to the first layer. A method for manufacturing a piezoelectric device in which a position having the highest zirconium concentration in the second layer is in the third layer and a position having the highest silicon concentration in the first layer includes the steps of: forming the first layer on the substrate; forming an elemental layer on the first layer, the elemental layer containing at least one selected from the group consisting of iron, silicon, and metals other than zirconium, semi-metals, and semiconductors, and heating the elemental layer to form the second layer made of an oxide; and forming a zirconium layer containing zirconium on the second layer, and heating the zirconium layer to form the third layer made of zirconium oxide. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an ink jet recording apparatus according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the recording head according to the first embodiment. [Diagram 3] 3 is a plan view of a flow path forming substrate of the recording head according to the first embodiment. FIG. [Figure 4] 1 is a cross-sectional view of a recording head according to a first embodiment. [Diagram 5] 1 is a cross-sectional view of a recording head according to a first embodiment. [Figure 6] 5A to 5C are diagrams illustrating a method for manufacturing the piezoelectric device according to the first embodiment. [Figure 7]FIG. 1 is a diagram showing the analysis results by STEM-EDS in Test Example 1. [Figure 8] FIG. 1 is a diagram showing the analysis results by STEM-EDS in Test Example 1. [Figure 9] FIG. 1 is a diagram showing the analysis results by STEM-EDS in Test Example 1. [Figure 10] 1 is a STEM image of sample 1. [Figure 11] 1 is a STEM image of sample 4. [Figure 12] 1 is a STEM image of sample 8. [Figure 13] 1 is a STEM image of sample 10. [Figure 14] 13 is a graph showing the results of leakage current. [Figure 15] This is a STEM image of sample 16. [Figure 16] STEM image of sample 17. [Figure 17] STEM image of sample 18. [Figure 18] This is a STEM image of sample 19. [Figure 19] 1 is a STEM image of sample 20. [Figure 20] FIG. 13 shows the results of STEM-EDS analysis of sample 20. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described in detail below based on the embodiments. However, the following description shows one aspect of the present invention, and can be arbitrarily modified within the scope of the present invention. In each drawing, the same reference numerals indicate the same members, and the description is omitted as appropriate. In each drawing, X, Y, and Z represent three spatial axes that are mutually orthogonal. In this specification, the directions along these axes are the X direction, the Y direction, and the Z direction. The direction in which the arrow in each drawing points is the positive (+) direction, and the opposite direction to the arrow is the negative (-) direction. In addition, the three spatial axes of X, Y, and Z, which are not limited to the positive and negative directions, are described as the X axis, the Y axis, and the Z axis. In each of the following embodiments, the "first direction" is the -Z direction, and the "second direction" is the +Z direction, as an example. In addition, viewing in a direction along the Z axis is called "planar view."

[0011] Typically, the Z axis is a vertical axis, and the +Z direction corresponds to the downward direction in the vertical direction. However, the Z axis does not have to be a vertical axis. Also, the X axis, the Y axis, and the Z axis are typically perpendicular to each other, but are not limited to this, and may intersect at an angle within a range of 80° to 100°, for example.

[0012] (Embodiment 1) FIG. 1 is a diagram illustrating a schematic diagram of an ink jet recording apparatus 1, which is an example of a liquid ejecting apparatus according to a first embodiment of the present invention.

[0013] 1, an inkjet recording device 1, which is an example of a liquid ejection device, is a printing device that ejects and impacts ink, which is a type of liquid, onto a medium S, such as printing paper, as ink droplets, and prints images, etc., by forming an arrangement of dots on the medium S. Note that the medium S can be made of any material, such as a resin film or cloth, in addition to recording paper.

[0014] In the following, of the three spatial axes X, Y, and Z, the movement direction of the recording head 2 described later (in other words, the main scanning direction) is defined as the X axis, the transport direction of the medium S perpendicular to the main scanning direction is defined as the Y axis, a plane parallel to the nozzle surface in which the nozzles 21 of the recording head 2 (see FIG. 2) are formed is defined as the XY plane, the direction intersecting the nozzle surface, i.e., the direction perpendicular to the XY plane in this embodiment, is defined as the Z axis, and ink droplets are ejected in the +Z direction along the Z axis.

[0015] The inkjet recording device 1 includes a liquid container 3, a transport mechanism 4 that feeds out the medium S, a control unit 5 that serves as a control section, a moving mechanism 6, and an inkjet recording head 2 (hereinafter also simply referred to as the recording head 2).

[0016] The liquid container 3 individually stores multiple types (e.g., multiple colors) of ink to be ejected from the recording head 2. Examples of the liquid container 3 include a cartridge that is detachable from the inkjet recording device 1, a bag-shaped ink pack made of a flexible film, and an ink tank that can be refilled with ink. Although not specifically shown, the liquid container 3 stores multiple types of ink with different colors and types.

[0017] Although not specifically shown, the control unit 5 includes, for example, a control device such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage device such as a semiconductor memory. The control unit 5 comprehensively controls each element of the inkjet recording device 1, i.e., the transport mechanism 4, the movement mechanism 6, the recording head 2, etc., by the control device executing a program stored in the storage device.

[0018] The transport mechanism 4 is controlled by the control unit 5 to transport the medium S in the Y direction, and has, for example, a transport roller 4a. Note that the transport mechanism 4 that transports the medium S is not limited to the transport roller 4a, and may transport the medium S by a belt or a drum.

[0019] The moving mechanism 6 is controlled by the control unit 5 to reciprocate the recording head 2 in the +X direction and the -X direction along the X axis.

[0020] Specifically, the movement mechanism 6 of this embodiment includes a conveyor 7 and a conveyor belt 8. The conveyor 7 is a substantially box-shaped structure, a so-called carriage, that houses the recording head 2, and is fixed to the conveyor belt 8. The conveyor belt 8 is an endless belt that is stretched along the X-axis. The conveyor belt 8 rotates under the control of the control unit 5, so that the recording head 2 moves back and forth together with the conveyor 7 in the +X and -X directions along a guide rail (not shown). It is also possible to mount the liquid container 3 on the conveyor 7 together with the recording head 2.

[0021] The recording head 2 ejects ink supplied from the liquid container 3 as ink droplets from each of the multiple nozzles 21 in the +Z direction onto the medium S under the control of the control unit 5. The ejection of ink droplets from the recording head 2 is performed in parallel with the transport of the medium S by the transport mechanism 4 and the reciprocating movement of the recording head 2 by the movement mechanism 6, thereby forming an image in ink on the surface of the medium S, that is, printing is performed. Here, the recording head 2 is an example of a "piezoelectric device."

[0022] Fig. 2 is an exploded perspective view of an ink jet recording head 2 which is an example of a liquid jet head of this embodiment. Fig. 3 is a plan view of a flow path forming substrate 10 of the recording head 2. Fig. 4 is a cross-sectional view of the recording head 2 taken along line AA' in Fig. 3. Fig. 5 is a cross-sectional view taken along line BB' in Fig. 3.

[0023] As shown in the figure, the recording head 2 of this embodiment includes a flow path forming substrate 10 as an example of a "substrate." The flow path forming substrate 10 is made of a silicon substrate, a glass substrate, an SOI substrate, or any of various ceramic substrates.

[0024] In the flow path forming substrate 10, a plurality of pressure chambers 12 are arranged side by side along the +X direction which is a first direction. The plurality of pressure chambers 12 are arranged on a straight line along the +X direction so that their positions in the +Y direction are the same. The pressure chambers 12 adjacent to each other in the +X direction are partitioned by partition walls 11. Of course, the arrangement of the pressure chambers 12 is not particularly limited to this, and for example, the pressure chambers 12 arranged side by side in the +X direction may be arranged in a so-called staggered arrangement in which every other pressure chamber 12 is shifted in the +Y direction.

[0025] Furthermore, the shape of the pressure chamber 12 in this embodiment when viewed in the +Z direction may be a rectangle, a parallelogram, or a rectangle with semicircular ends at both ends in the longitudinal direction, i.e., a rounded rectangle, an ellipse, an egg, or other oval shape, a circle, a polygon, etc. This pressure chamber 12 corresponds to a "recess" provided in the "substrate".

[0026] On the +Z direction side of the flow passage forming substrate 10, a communication plate 15 and a nozzle plate 20 are laminated in this order.

[0027] The communication plate 15 is provided with a nozzle communication passage 16 that connects the pressure chamber 12 and the nozzle 21 . The communication plate 15 is provided with a first manifold portion 17 and a second manifold portion 18 which constitute a part of a manifold 100 which serves as a common liquid chamber to which the multiple pressure chambers 12 are commonly connected. The first manifold portion 17 is provided so as to penetrate the communication plate 15 in the +Z direction. The second manifold portion 18 is provided so as to open on the surface on the +Z direction side, without penetrating the communication plate 15 in the +Z direction.

[0028] Furthermore, in the communicating plate 15, a supply communication passage 19 that communicates with the Y-axis end of the pressure chamber 12 is provided independently for each pressure chamber 12. The supply communication passage 19 communicates between the second manifold portion 18 and the pressure chamber 12, and supplies ink in the manifold 100 to the pressure chamber 12.

[0029] As the communicating plate 15, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate such as a stainless steel substrate, or the like can be used. Note that it is preferable that the communicating plate 15 is made of a material having approximately the same thermal expansion coefficient as the flow path forming substrate 10. By using materials having approximately the same thermal expansion coefficient for the flow path forming substrate 10 and the communicating plate 15 in this manner, it is possible to reduce the occurrence of warping due to heat caused by the difference in thermal expansion coefficient.

[0030] The nozzle plate 20 is provided on the side of the communication plate 15 opposite to the flow path forming substrate 10, that is, on the surface on the +Z direction side.

[0031] The nozzle plate 20 is formed with nozzles 21 that communicate with each pressure chamber 12 via the nozzle communication passage 16. In this embodiment, the nozzles 21 are arranged in two rows, one in a row along the +X direction, and the other in a row spaced apart in the +Y direction. That is, the nozzles 21 in each row are arranged so that their positions in the +Y direction are the same. Of course, the arrangement of the nozzles 21 is not particularly limited to this, and for example, the nozzles 21 may be arranged in a so-called staggered arrangement, in which every other nozzle 21 arranged in the +X direction is arranged at a position shifted in the +Y direction. As such a nozzle plate 20, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate such as a stainless steel substrate, an organic material such as a polyimide resin, or the like can be used. Note that it is preferable that the nozzle plate 20 is made of a material having a thermal expansion coefficient substantially equal to that of the communication plate 15. By using materials having a thermal expansion coefficient substantially equal to that of the communication plate 15 in this way, it is possible to reduce the occurrence of warping due to heat caused by the difference in thermal expansion coefficient.

[0032] A vibration plate 50 and a piezoelectric actuator 300 are laminated in this order on the surface of the flow path forming substrate 10 on the -Z direction side. That is, the flow path forming substrate 10, the vibration plate 50, and the piezoelectric actuator 300 are laminated in this order in the -Z direction.

[0033] As shown in FIG. 2 and FIG. 4, a protective substrate 30 having approximately the same size as the flow path forming substrate 10 is bonded to the surface of the flow path forming substrate 10 in the -Z direction. The protective substrate 30 has a holding portion 31 which is a space for protecting the piezoelectric actuator 300. The holding portion 31 is provided independently for each row of the piezoelectric actuators 300 arranged side by side in the +X direction, and two holding portions 31 are formed side by side in the +Y direction. In addition, the protective substrate 30 is provided with a through hole 32 penetrating in the +Z direction between the two holding portions 31 arranged side by side in the +Y direction. The ends of the individual lead electrodes 91 and the common lead electrode 92 drawn from the electrodes of the piezoelectric actuators 300 are extended so as to be exposed in the through hole 32, and the individual lead electrodes 91 and the common lead electrode 92 are electrically connected to the wiring substrate 120 in the through hole 32.

[0034] 4, a case member 40 is fixed onto the protective substrate 30. The case member 40 defines, together with the flow path forming substrate 10, a manifold 100 that communicates with the multiple pressure chambers 12. The case member 40 has substantially the same shape as the above-mentioned communicating plate 15 in a plan view, and is joined to the protective substrate 30 and also to the above-mentioned communicating plate 15. In this embodiment, the case member 40 is joined to the communicating plate 15. Although not particularly shown, the case member 40 is also joined to the protective substrate 30.

[0035] Such a case member 40 has a recess 41 on the protective substrate 30 side, the recess 41 being deep enough to accommodate the flow path forming substrate 10 and the protective substrate 30. The recess 41 has an opening area larger than the surface of the protective substrate 30 bonded to the flow path forming substrate 10. The opening surface of the recess 41 on the nozzle plate 20 side is sealed by the communication plate 15 while the flow path forming substrate 10 and the like are accommodated in the recess 41. As a result, a third manifold portion 42 is defined by the case member 40 and the flow path forming substrate 10 on the outer periphery of the flow path forming substrate 10. The manifold 100 of this embodiment is configured by the first manifold portion 17 and the second manifold portion 18 provided on the communication plate 15, and the third manifold portion 42 defined by the case member 40 and the flow path forming substrate 10. The manifold 100 is provided continuously over the +X direction in which the pressure chambers 12 are arranged side by side, and the supply communication passages 19 that communicate between each pressure chamber 12 and the manifold 100 are arranged side by side in the +X direction. The case member 40 is provided with an inlet 44 that communicates with the manifold 100 and supplies ink to each manifold 100. The case member 40 is also provided with a connection port 43 that communicates with a through hole 32 of the protection substrate 30, which will be described in detail later, and through which the wiring substrate 120 is inserted.

[0036] Further, a compliance substrate 45 is provided on the surface of the communication plate 15 on the +Z direction side where the first manifold portion 17 and the second manifold portion 18 open. This compliance substrate 45 seals the openings of the first manifold portion 17 and the second manifold portion 18 on the liquid ejection surface 20a side. In this embodiment, such a compliance substrate 45 includes a sealing film 46 made of a flexible thin film, and a fixed substrate 47 made of a hard material such as metal. Since the region of the fixed substrate 47 facing the manifold 100 is an opening 48 that is completely removed in the thickness direction, one surface of the manifold 100 is a compliance portion 49 that is a flexible portion sealed only by the sealing film 46 that has flexibility.

[0037] The diaphragm 50 and the piezoelectric actuator 300 of this embodiment will be described.

[0038] As shown in FIG. 4 and FIG. 5, the piezoelectric actuator 300 includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80, which are sequentially stacked from the +Z direction side, which is the vibration plate 50 side, toward the -Z direction side. The piezoelectric actuator 300 is a pressure generating means that generates a pressure change in the ink in the pressure chamber 12. Such a piezoelectric actuator 300 is also called a piezoelectric element, and refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In addition, a portion where a piezoelectric strain occurs in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is called an active portion 310. In contrast, a portion where no piezoelectric strain occurs in the piezoelectric layer 70 is called an inactive portion. That is, the active portion 310 refers to a portion where the piezoelectric layer 70 is sandwiched between the first electrode 60 and the second electrode 80. In this embodiment, an active portion 310 is formed for each pressure chamber 12, which is a recess. That is, the piezoelectric actuator 300 has a plurality of active sections 310 formed therein. In general, one of the electrodes of the active sections 310 is an individual electrode independent of each other for each active section 310, and the other electrode is configured as a common electrode common to the plurality of active sections 310. In this embodiment, the first electrode 60 constitutes an individual electrode, and the second electrode 80 constitutes a common electrode. Of course, the first electrode 60 may constitute a common electrode, and the second electrode 80 may constitute an individual electrode. In this piezoelectric actuator 300, a portion facing the pressure chamber 12 in the Z-axis direction becomes a flexible portion, and a portion outside the pressure chamber 12 becomes a non-flexible portion.

[0039] Specifically, as shown in Figs. 3 to 5, the first electrode 60 is separated for each pressure chamber 12 to form an individual electrode independent for each active section 310. The first electrode 60 is formed with a width narrower than the width of the pressure chamber 12 in the +X direction. That is, in the +X direction, the end of the first electrode 60 is located inside the region facing the pressure chamber 12. Also, as shown in Fig. 4, the end of the first electrode 60 on the nozzle 21 side is disposed outside the pressure chamber 12 in the Y axis. An individual lead electrode 91, which is a lead-out wiring, is connected to the end of the first electrode 60 disposed outside the pressure chamber 12 in the Y axis.

[0040] The first electrode 60 is made of a conductive material, such as iridium (Ir), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), chromium (Cr), nickel chromium (NiCr), tungsten (W), titanium (Ti), titanium oxide (TiO X ), titanium tungsten (TiW), etc. can be used.

[0041] As shown in Figs. 3 to 5, the piezoelectric layer 70 has a predetermined width in the +Y direction and is continuously provided over the +X direction. The width of the piezoelectric layer 70 in the +Y direction is longer than the length of the pressure chamber 12 in the +Y direction, which is the longitudinal direction of the pressure chamber 12. Therefore, on both sides of the pressure chamber 12 in the +Y direction and the -Y direction, the piezoelectric layer 70 is extended to the outside of the region facing the pressure chamber 12. The end of such a piezoelectric layer 70 on the opposite side to the nozzle 21 in the Y axis is located outside the end of the first electrode 60. That is, the end of the first electrode 60 on the opposite side to the nozzle 21 is covered by the piezoelectric layer 70. In addition, the end of the piezoelectric layer 70 on the nozzle 21 side is located inside the end of the first electrode 60, and the end of the first electrode 60 on the nozzle 21 side is not covered by the piezoelectric layer 70. As described above, the individual lead electrode 91 made of gold (Au) or the like is connected to the end of the first electrode 60 that extends to the outside of the piezoelectric layer .

[0042] Further, the piezoelectric layer 70 is formed with recesses 71 corresponding to the partition walls 11. The width of the recesses 71 in the +X direction is the same as or wider than the width of the partition walls 11. In this embodiment, the width of the recesses 71 in the +X direction is wider than the width of the partition walls 11. This suppresses the rigidity of the parts of the vibration plate 50 facing both ends of the pressure chambers 12 in the +X direction and the -X direction, that is, the arms of the vibration plate 50, and thus the piezoelectric actuator 300 can be displaced satisfactorily. The recesses 71 may be provided penetrating the piezoelectric layer 70 in the +Z direction, which is the thickness direction, or may be provided halfway through the thickness direction of the piezoelectric layer 70 without penetrating the piezoelectric layer 70 in the +Z direction. That is, the piezoelectric layer 70 may be completely removed from the bottom surface of the recesses 71 in the +Z direction, or a part of the piezoelectric layer 70 may remain.

[0043] Such a piezoelectric layer 70 is made of a piezoelectric material made of a composite oxide having a perovskite structure represented by the general formula ABO3. In this embodiment, lead zirconate titanate (PZT; Pb(Zr,Ti)O3) is used as the piezoelectric material. By using PZT as the piezoelectric material, a piezoelectric layer 70 having a relatively large piezoelectric constant d31 can be obtained.

[0044] In a composite oxide having a perovskite structure represented by the general formula ABO3, 12 oxygen atoms are coordinated to the A site, and 6 oxygen atoms are coordinated to the B site to form an octahedron. In this embodiment, lead (Pb) is located at the A site, and zirconium (Zr) and titanium (Ti) are located at the B site.

[0045] The piezoelectric material is not limited to the above PZT. Other elements may be included in the A site or B site. For example, the piezoelectric material may be a perovskite material such as barium zirconate titanate (Ba(Zr,Ti)O3), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O3), lead magnesium zirconate titanate (Pb(Zr,Ti)(Mg,Nb)O3), or lead zirconate titanate niobate containing silicon (Pb(Zr,Ti,Nb)O3).

[0046] Alternatively, the piezoelectric material may be a material with a reduced Pb content, so-called low-lead material, or a material that does not use Pb, so-called lead-free material. If a low-lead material is used as the piezoelectric material, the amount of Pb used can be reduced. Also, if a lead-free material is used as the piezoelectric material, Pb can be eliminated. Therefore, the use of low-lead or lead-free materials as piezoelectric materials can reduce the environmental impact.

[0047] An example of a lead-free piezoelectric material is a BFO-based material containing bismuth ferrite (BFO; BiFeO3). In BFO, bismuth (Bi) is located at the A site, and iron (Fe) is located at the B site. Other elements may be added to BFO. For example, at least one element selected from manganese (Mn), aluminum (Al), lanthanum (La), barium (Ba), titanium (Ti), cobalt (Co), cerium (Ce), samarium (Sm), chromium (Cr), potassium (K), lithium (Li), calcium (Ca), strontium (Sr), vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), nickel (Ni), zinc (Zn), praseodymium (Pr), neodymium (Nd), and europium (Eu) may be added to BFO.

[0048] Another example of a lead-free piezoelectric material is a KNN-based material containing potassium sodium niobate (KNN; KNaNbO3). Other elements may be added to KNN. For example, at least one element selected from manganese (Mn), lithium (Li), barium (Ba), calcium (Ca), strontium (Sr), zirconium (Zr), titanium (Ti), bismuth (Bi), tantalum (Ta), antimony (Sb), iron (Fe), cobalt (Co), silver (Ag), magnesium (Mg), zinc (Zn), copper (Cu), vanadium (V), chromium (Cr), molybdenum (Mo), tungsten (W), nickel (Ni), aluminum (Al), silicon (Si), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm) and europium (Eu) may be added to KNN.

[0049] The piezoelectric material includes a material having a composition with a partial deficiency of an element, a material having a composition with an excess of a part of an element, and a material having a composition with a part of an element substituted with another element. As long as the basic characteristics of the piezoelectric layer 70 are not changed, the piezoelectric material according to this embodiment includes a material having a composition that is deviated from the stoichiometric composition due to a deficiency or excess, and a material having a part of an element substituted with another element. Of course, the piezoelectric material that can be used in this embodiment is not limited to the above-mentioned materials containing Pb, Bi, Na, K, etc.

[0050] As shown in FIG. 2 to FIG. 5, the second electrode 80 is provided continuously on the −Z direction side of the piezoelectric layer 70, which is the opposite side to the first electrode 60, and constitutes a common electrode common to a plurality of active sections 310. The second electrode 80 is provided continuously over the +X direction so that the +Y direction has a predetermined width. The second electrode 80 is also provided on the inner surface of the recess 71, that is, on the side surface of the recess 71 of the piezoelectric layer 70 and on the vibration plate 50 which is the bottom surface of the recess 71. Of course, the second electrode 80 may be provided only on a part of the inner surface of the recess 71, or may not be provided over the entire inner surface of the recess 71. That is, in this embodiment, the second electrode 80 is not provided on the end portions of the piezoelectric actuator 300 on the +Y direction side and the −Y direction side on the flow path forming substrate 10, and the vibration plate 50 is provided exposed on the surface in the −Z direction.

[0051] The second electrode 80 may be made of a material such as a precious metal material, such as iridium (Ir), platinum (Pt), palladium (Pd), or gold (Au), or a conductive oxide, such as lanthanum nickel oxide (LNO). The second electrode 80 may be made of a laminate of a plurality of materials. The second electrode 80 is preferably made of a material containing iridium (Ir) and titanium (Ti). In this embodiment, the second electrode 80 is a laminated electrode of iridium (Ir) and titanium (Ti).

[0052] Furthermore, an individual lead electrode 91, which is an extraction wiring, is drawn out from the first electrode 60. A common lead electrode 92, which is an extraction wiring, is drawn out from the second electrode 80. The ends of the individual lead electrodes 91 and the common lead electrode 92 opposite to the ends connected to the piezoelectric actuator 300 are connected to the wiring board 120, which is flexible as described above. A drive circuit 121 having a switching element for driving the piezoelectric actuator 300 is mounted on the wiring board 120.

[0053] As shown in FIG. 5, the vibration plate 50 has a first layer 51, a second layer 52, and a third layer 53, which are laminated in this order in the -Z direction. That is, the vibration plate 50 has a first layer 51, a third layer 53 disposed between the first layer 51 and the piezoelectric actuator 300, and a second layer 52 disposed between the first layer 51 and the third layer 53. The first layer 51 is disposed on the side of the vibration plate 50 closest to the flow path forming substrate 10, that is, on the +Z direction side, and is in contact with a surface on the -Z direction side of the flow path forming substrate 10. The third layer 53 is disposed on the side of the vibration plate 50 closest to the -Z direction, and is in contact with the piezoelectric actuator 300. The second layer 52 is interposed between the first layer 51 and the third layer 53. 4 and 5, for convenience of explanation, the interface between the layers constituting the vibration plate 50 is clearly shown, but the interface does not have to be clear, and for example, the constituent materials of two adjacent layers may be mixed near the interface between the two layers. The vibration plate 50 having such a first layer 51, second layer 52, and third layer 53 is provided continuously over the entire surface of the flow path forming substrate 10 on the -Z direction side.

[0054] The first layer 51 is a layer containing silicon (Si) as a constituent element. Specifically, the first layer 51 is an elastic film made of, for example, silicon oxide (SiO2). Here, the first layer 51 may contain small amounts of elements such as zirconium (Zr), titanium (Ti), iron (Fe), chromium (Cr), or hafnium (Hf) as impurities, in addition to silicon oxide and its constituent elements. Such impurities have the effect of softening silicon oxide (SiO2).

[0055] In this manner, the first layer 51 of the present embodiment contains, for example, silicon oxide. Such a first layer 51 can be formed with better productivity by thermally oxidizing the flow path forming substrate 10 made of a silicon single crystal substrate, as compared with the case of forming the first layer 51 by a sputtering method.

[0056] Silicon in first layer 51 may exist in the form of an oxide, or may exist in the form of an element, a nitride, an oxynitride, etc. Impurities in first layer 51 may be elements that are inevitably mixed in when first layer 51 is formed, or may be elements that are intentionally mixed in first layer 51.

[0057] The thickness T1 of the first layer 51 is determined according to the thickness T and width W of the diaphragm 50. The thickness T1 of the first layer 51 is preferably within a range of, for example, 100 nm or more and 20,000 nm or less, and more preferably within a range of 500 nm or more and 1,500 nm or less.

[0058] The third layer 53 is a layer containing zirconium (Zr) as a constituent element. Specifically, the third layer 53 is an insulating film made of, for example, zirconium oxide (ZrO2). Here, the third layer 53 may contain small amounts of elements such as titanium (Ti), iron (Fe), chromium (Cr) or hafnium (Hf) as impurities in addition to zirconium oxide and its constituent elements. Such impurities have the effect of softening zirconium oxide (ZrO2). However, the concentration of impurities contained in the third layer 53 is lower than the concentration of impurities contained in the second layer 52, which will be described in detail later.

[0059] Thus, the third layer 53 contains, for example, zirconium oxide. Such a third layer 53 can be obtained, for example, by forming a layer of simple zirconium by sputtering or the like, and then thermally oxidizing the layer. Therefore, when forming the third layer 53, the third layer 53 can be easily obtained with a desired thickness. In addition, since zirconium oxide has excellent electrical insulation properties, mechanical strength, and toughness, the characteristics of the diaphragm 50 can be improved by including zirconium oxide in the third layer 53. In addition, for example, when the piezoelectric layer 70 is made of lead zirconate titanate, the third layer 53 contains zirconium oxide, which has the advantage that the piezoelectric layer 70 that is preferentially oriented in the (100) plane with a high orientation rate can be easily obtained when forming the piezoelectric layer 70.

[0060] Zirconium in the third layer 53 may exist in the form of an oxide, or may exist in the form of an element, a nitride, an oxynitride, or the like. The impurities in the third layer 53 may be elements that are inevitably mixed in when the third layer 53 is formed, or may be elements that are intentionally mixed in the third layer 53. For example, the impurities are impurities contained in a zirconium target used when the third layer 53 is formed by a sputtering method.

[0061] The thickness T3 of the third layer 53 is determined according to the thickness T and width W of the diaphragm 50. The thickness T3 of the third layer 53 is preferably within the range of 100 nm to 20000 nm, for example.

[0062] The second layer 52 is interposed between the first layer 51 and the third layer 53. This prevents contact between the first layer 51 and the third layer 53. Therefore, compared to a configuration in which the first layer 51 and the third layer 53 are in contact with each other, reduction of silicon oxide in the first layer 51 by zirconium in the third layer 53 is reduced.

[0063] In addition, the second layer 52 absorbs impurities in the third layer 53 and functions as an impurity absorbing layer that prevents impurities from accumulating on the second layer 52 side of the third layer 53 and causing the third layer 53 to deteriorate, thereby preventing the generation of gaps (voids).

[0064] The second layer 52 includes at least one element selected from the group consisting of metals other than iron, silicon, and zirconium, semi-metals, and semiconductors. The elements of the second layer 52 may exist in the form of oxides, or may exist in the form of simple substances, nitrides, or oxynitrides. The second layer 52 may include only one metal element, or may include two or more metal elements. The second layer 52 may include only one semi-metal or semiconductor element, or may include two or more. The second layer 52 may include any one or a combination of two or more of metals, semi-metals, and semiconductors.

[0065] Moreover, the second layer 52 preferably contains at least one metal element selected from chromium (Cr), titanium (Ti), and aluminum (Al) as a constituent element. Such a metal element of the second layer 52 may exist in the form of an oxide, or may exist in the form of a simple substance, a nitride, or an oxynitride. The second layer 52 may contain only one of the above-mentioned metal elements, or may contain two or more of them.

[0066] Moreover, the second layer 52 is preferably a layer containing a metal element that is less easily oxidized than zirconium, and the second layer 52 is preferably composed of, for example, an oxide of the metal element. In other words, the second layer 52 preferably contains a metal element having a higher oxide formation free energy than zirconium. The metal element preferably contains any one of chromium, titanium, and aluminum, and the second layer 52 is preferably composed of an oxide of the metal element. The magnitude relationship of the oxide formation free energy can be evaluated, for example, based on the known Ellingham diagram.

[0067] Since the second layer 52 contains a metal element that is less easily oxidized than zirconium, the reduction of silicon oxide contained in the first layer 51 can be reduced compared to a configuration in which the metal element contained in the second layer 52 is more easily oxidized than zirconium, that is, compared to a configuration in which the oxide formation free energy of the metal element contained in the second layer 52 is smaller than the oxide formation free energy of zirconium. As a result, the adhesion between the first layer 51 and the third layer 53 can be increased compared to a configuration in which the second layer 52 is not used.

[0068] Furthermore, since the second layer 52 is made of oxides of chromium, titanium, and aluminum, the adhesion between the first layer 51 and the third layer 53 can be increased more than with simple substances, nitrides, and carbon-based materials.

[0069] Chromium is less easily oxidized than silicon. In other words, the free energy of formation of an oxide of chromium is greater than the free energy of formation of an oxide of silicon. Therefore, when chromium is contained as a metal element in the second layer 52, the reduction of silicon oxide contained in the first layer 51 can be reduced compared to when the second layer 52 does not contain a metal element that is less easily oxidized than silicon.

[0070] Furthermore, when the second layer 52 contains chromium, for example, chromium forms an oxide, and contains chromium oxide. Such a second layer 52 is obtained by forming a layer of simple chromium by a sputtering method or the like, and then thermally oxidizing the layer. Therefore, when forming the second layer 52, the second layer 52 of the desired thickness can be easily obtained.

[0071] Here, the chromium oxide contained in the second layer 52 may be in any of a polycrystalline, amorphous, or single crystalline state. However, when the chromium oxide contained in the second layer 52 has an amorphous structure, that is, is in an amorphous state, the compressive stress generated in the second layer 52 can be reduced compared to when the chromium oxide contained in the second layer 52 is in a polycrystalline or single crystalline state. As a result, the strain generated at the interface between the first layer 51 or the third layer 53 and the second layer 52 can be reduced.

[0072] The oxide of titanium or aluminum is easily moved by heat. Therefore, when the second layer 52 contains titanium or aluminum as a metal element, the adhesive strength between the first layer 51 or the third layer 53 and the second layer 52 can be increased by the anchor effect or chemical bond of the oxide of the metal element. Moreover, titanium easily forms an oxide together with silicon or zirconium. Therefore, when the second layer 52 contains titanium as a metal element, the adhesive strength between the first layer 51 and the second layer 52 can be increased by forming an oxide together with silicon, or the adhesive strength between the second layer 52 and the third layer 53 can be increased by forming an oxide together with zirconium.

[0073] Furthermore, when the second layer 52 contains titanium, for example, titanium constitutes an oxide, and the second layer 52 contains titanium oxide. Such a second layer 52 is obtained by forming a layer of simple titanium by a sputtering method or the like, and then thermally oxidizing the layer. Therefore, when forming the second layer 52, the second layer 52 of the desired thickness can be easily obtained.

[0074] Here, the titanium oxide contained in the second layer 52 may be in any state of polycrystal, amorphous, or single crystal. However, the titanium oxide contained in the second layer 52 is preferably in a polycrystal or single crystal state, and in particular, preferably has a rutile structure as a crystal structure. Among the crystal structures that titanium oxide can have, the rutile structure is the most stable, and is unlikely to change to a polymorph such as anatase or blockite even if it moves due to heat. Therefore, the thermal stability of the second layer 52 can be improved compared to when the crystal structure of the titanium oxide contained in the second layer 52 is another crystal structure.

[0075] Furthermore, when the second layer 52 contains aluminum, for example, aluminum constitutes an oxide, and the second layer 52 contains aluminum oxide. Such a second layer 52 is obtained by forming a layer of simple aluminum by a sputtering method or the like, and then thermally oxidizing the layer. Therefore, when forming the second layer 52, the second layer 52 of the desired thickness can be easily obtained.

[0076] Here, the aluminum oxide contained in the second layer 52 may be in any state of polycrystal, amorphous or single crystal, and when in a polycrystal or single crystal state, it has a trigonal crystal structure.

[0077] In addition to the above-mentioned metal elements, the second layer 52 contains elements such as titanium (Ti), silicon (Si), iron (Fe), chromium (Cr), and hafnium (Hf) as impurities. The impurities contained in the second layer 52 are elements contained in the first layer 51 or the third layer 53. The impurities exist, for example, in the form of an oxide together with the metal elements of the second layer 52.

[0078] In addition, the second layer 52 has the highest impurity concentration. The "impurities in the second layer 52 and the third layer 53" referred to here means elements other than the constituent elements that are the main components of the second layer 52 and the third layer 53. The main components refer to the elements that are detected with the highest intensity in each layer, and the state of the main components contained in each layer is not particularly limited, and each may be present in the form of a simple substance, an oxide, a nitride, or an oxynitride. In other words, the "impurities in the second layer 52 and the third layer 53" means elements other than the above-mentioned metal elements that constitute the second layer 52 and the zirconium that constitutes the third layer 53. Therefore, the impurities in the second layer 52 and the third layer 53 also include silicon, which is a constituent element of the first layer 51. In addition, the fact that the impurity concentration in the second layer 52 and the third layer 53 is highest in the second layer 52 means that the position of highest concentration in the impurity concentration distribution in the -Z direction of the second layer 52 and the third layer 53 is present in the film of the second layer 52.

[0079] The second layer 52 absorbs impurities contained in the third layer 53, and the position where the concentration of the impurities is highest in the second layer 52 and the third layer 53 is located in the second layer 52, thereby making it possible to reduce the concentration of the impurities in the third layer 53. Therefore, it is possible to suppress the localization of impurities at the interface of the third layer 53 on the second layer 52 side, and to suppress the formation of gaps due to the impurities. Therefore, it is possible to suppress the reduction in the toughness of the vibration plate 50 due to the gaps, and to suppress the vibration plate 50 from being broken when an external force is applied to the vibration plate 50 due to the deformation of the piezoelectric actuator 300. In addition, by providing the second layer 52 containing the above-mentioned metal element as a constituent element, it is possible to suppress the diffusion of silicon from the first layer 51 side to the third layer 53. Therefore, it is possible to suppress the formation of a compound of silicon and zirconium, and to suppress the occurrence of gaps between the second layer 52 and the third layer 53 due to impurities derived from silicon.

[0080] Furthermore, by providing the second layer 52, it is possible to prevent a gap from being formed at the interface between the third layer 53 and the second layer 52, and therefore it is possible to prevent moisture from penetrating into the interface between the second layer 52 and the third layer 53 from the end face side of the piezoelectric actuator 300. Therefore, it is possible to prevent the zirconium of the third layer 53 from being embrittled by moisture, and it is possible to prevent delamination between the third layer 53 and the layers above and below the third layer 53, and damage such as cracks in the third layer 53.

[0081] In addition, in the diaphragm 50, the position of the highest zirconium concentration is in the third layer 53, and the position of the highest silicon concentration is in the first layer 51. That is, in the diaphragm 50, in the zirconium concentration distribution in the -Z direction, the position of the highest concentration exists in the film of the third layer 53. In addition, in the diaphragm 50, in the silicon concentration distribution in the -Z direction, the position of the highest concentration exists in the film of the first layer 51. Since the third layer 53 is mainly composed of zirconium, the concentration of zirconium is approximately the same and the highest concentration throughout the -Z direction of the third layer 53. Similarly, since the first layer 51 is mainly composed of silicon, the concentration of silicon is approximately the same and the highest concentration throughout the -Z direction.

[0082] When the impurities contained in the second layer 52 and the third layer 53 are at least one of iron and chromium, the impurity concentration in the third layer 53 is preferably higher than the impurity concentration in the first layer 51. By reducing the impurity concentration in the first layer 51, it is possible to suppress localization of impurities at the interface of the first layer 51 on the second layer 52 side, and suppress the formation of gaps at the interface. This makes it possible to suppress moisture penetration from the interface, suppress embrittlement of the second layer 52 and the first layer 51 due to moisture, and suppress delamination between the second layer 52 and the first layer 51 and damage such as cracks in the second layer 52 and the first layer 51.

[0083] The thickness T2 of the second layer 52 is determined by the material and impurities of the second layer 52. For example, when the second layer 52 is made of an oxide of titanium, and the impurities of the second layer 52 and the third layer 53 are compounds containing at least one of iron and chromium, the thickness of the second layer 52 in the -Z direction is preferably 10 nm to 40 nm. By setting the thickness of the second layer 52 to 10 nm to 40 nm in this way, the position where the concentration of the impurities, iron and chromium, is the highest can be located within the second layer 52. Note that, when the thickness T2 of the second layer 52 is thicker than the above-mentioned thickness, the constituent elements of the second layer 52 are diffused from the second layer 52 to the third layer 53 in large amounts, and the impurities of the third layer 53 are less likely to be absorbed by the second layer 52. As a result, the position where the concentration of the impurities is the highest does not exist within the second layer 52, and a layer where the impurities are localized is formed near the interface of the third layer 53 on the second layer 52 side.

[0084] Furthermore, for example, when the second layer 52 is made of an oxide of titanium, and the impurities of the second layer 52 and the third layer 53 are compounds containing silicon, the thickness of the second layer 52 in the -Z direction is preferably 10 nm to 60 nm, and more preferably 20 nm to 60 nm. By setting the thickness of the second layer 52 to be 10 nm to 60 nm, and more preferably 20 nm to 60 nm, in this manner, the position where the concentration of silicon, which is an impurity, is the highest, can be located within the second layer 52.

[0085] Furthermore, for example, when the second layer 52 is made of an oxide of chromium, and the impurities in the second layer 52 and the third layer 53 are compounds containing silicon, the thickness of the second layer 52 in the -Z direction is preferably 5 nm or more and 30 nm or less. By setting the thickness of the second layer 52 to be 5 nm or more and 30 nm or less in this manner, the position where the concentration of silicon, which is an impurity, is the highest, can be located within the second layer 52.

[0086] On the other hand, if the thickness T2 is too thin, the effect of the second layer 52 in reducing the diffusion of elemental silicon from the first layer 51 tends to decrease depending on the type of constituent elements contained in the second layer 52. For example, when the second layer 52 is made of titanium oxide, if the thickness T2 is too thin, silicon diffused from the first layer 51 to the second layer 52 may reach the third layer 53 depending on the conditions of the heat treatment during production. On the other hand, if the thickness T2 is too thick, the heat treatment during production of the second layer 52 may not be performed sufficiently, or the thermal oxidation may take a long time, which may adversely affect other layers.

[0087] By absorbing the impurities in the third layer 53 into the second layer 52 in this way, the position where the concentration of the impurities in the second layer 52 and the third layer 53 is the highest can be made to exist in the second layer 52. Therefore, the concentration of the impurities in the third layer 53 can be made low. Therefore, it is possible to suppress the localization of the impurities at the interface of the third layer 53 on the second layer 52 side, and to suppress the formation of gaps due to the impurities at the interface between the second layer 52 and the third layer 53. This suppresses the reduction in the toughness of the vibration plate 50 due to the gaps, and suppresses the vibration plate 50 from being broken when an external force is applied to the vibration plate 50 due to the deformation of the piezoelectric actuator 300. In addition, by providing the second layer 52 containing the above-mentioned metal element as a constituent element, it is possible to suppress the diffusion of silicon from the first layer 51 side to the third layer 53. Therefore, it is possible to suppress the formation of a compound of silicon and zirconium, and to suppress the generation of gaps between the second layer 52 and the third layer 53 due to impurities derived from silicon.

[0088] The impurities in the third layer 53 may exist in the form of an oxide, an element, a nitride, or an oxynitride.

[0089] 6A to 6C are diagrams for explaining a method for manufacturing a piezoelectric device. Hereinafter, a method for manufacturing a piezoelectric device will be explained with reference to FIG. 6, taking the case of manufacturing a recording head as an example.

[0090] 6, the method for manufacturing the recording head includes a substrate preparation step S10, a vibration plate formation step S20, a piezoelectric actuator formation step S30, and a pressure chamber formation step S40. Here, the vibration plate formation step S20 includes a first layer formation step S21, a second layer formation step S22, and a third layer formation step S23. Each step will be described below in order.

[0091] The substrate preparation step S10 is a step of preparing a substrate to become the flow path forming substrate 10. The substrate is, for example, a silicon single crystal substrate.

[0092] The diaphragm forming process S20 is a process for forming the above-mentioned diaphragm 50, and is performed after the substrate preparing process S 10. In the diaphragm forming process S20, a first layer forming process S21, a second layer forming process S22, and a third layer forming process S23 are performed in this order.

[0093] The first layer forming step S21 is a step of forming the above-mentioned first layer 51. In the first layer forming step S21, for example, one surface of the silicon single crystal substrate prepared in the substrate preparation step S10 is thermally oxidized to form the first layer 51 made of silicon oxide (SiO2). Note that the method of forming the first layer 51 is not particularly limited to this, and the first layer 51 may be formed by, for example, a sputtering method, a chemical vapor deposition method (CVD method), a vacuum deposition method (PVD method), an atomic layer deposition method (ALD method), a spin coating method, or the like.

[0094] The second layer forming step S22 is a step of forming the second layer 52 described above. In the second layer forming step S22, for example, a chromium, titanium or aluminum elemental layer is formed on the first layer 51 by a sputtering method, and the elemental layer is heated and oxidized to form the second layer 52 composed of chromium oxide, titanium oxide or aluminum oxide. The method of forming the second layer 52 is not particularly limited to this, and for example, a CVD method, a PVD method, an ALD method, a spin coating method, etc. may be used. Of course, as described above, the constituent elements of the second layer 52 are not limited to chromium, titanium or aluminum, and may be metals, semimetals and semiconductors other than iron, silicon and zirconium.

[0095] The third layer forming step S23 is a step of forming the aforementioned third layer 53. In the third layer forming step S23, for example, a zirconium layer of zirconium is formed on the first layer 51 by a sputtering method, and the zirconium layer is heated and oxidized to form the third layer 53 made of zirconium oxide. The diaphragm 50 is formed by the first layer forming step S21 and the third layer forming step S23. Note that the formation of the third layer 53 is not particularly limited to this, and for example, a CVD method, a PVD method, an ALD method, a spin coating method, or the like may be used.

[0096] In this way, by forming the second layer 52 and the third layer 53 by thermal oxidation, respectively, the impurities in the third layer 53 are diffused and absorbed into the second layer 52, and the position with the highest impurity concentration in the second layer 52 and the third layer 53 becomes the second layer 52. In other words, the impurity concentration in the third layer 53 can be reduced.

[0097] The piezoelectric actuator formation step S30 is a step of forming the piezoelectric actuator 300 described above, and is performed after the third layer formation step S23. In the piezoelectric actuator formation step S30, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are formed on the third layer 53 in this order.

[0098] Each of the first electrode 60 and the second electrode 80 is formed by a known film forming technique such as a sputtering method, and a known processing technique using a photolithography method, etching, etc. The piezoelectric layer 70 is formed, for example, by forming a precursor layer of the piezoelectric layer 70 by a sol-gel method, and baking and crystallizing the precursor layer. Of course, the method of forming the piezoelectric layer 70 is not particularly limited to this, and may be formed by, for example, a metal-organic decomposition (MOD) method, a sputtering method, a laser ablation method, etc. The piezoelectric layer 70 is formed into a predetermined shape by a known processing technique using a photolithography method, etching, etc.

[0099] After the piezoelectric actuator 300 is formed, if necessary, one of the two surfaces of the substrate after the formation, other than the surface on which the piezoelectric actuator 300 is formed, is ground by CMP (chemical mechanical polishing) or the like to flatten that surface or adjust the thickness of the substrate.

[0100] The pressure chamber forming step S40 is a step of forming the pressure chamber 12 described above, and is performed after the piezoelectric actuator forming step S30. In the pressure chamber forming step S40, for example, the pressure chamber 12 is formed by anisotropically etching a surface of the silicon single crystal substrate after the piezoelectric actuator 300 is formed, which is different from the surface on which the piezoelectric actuator 300 is formed. As a result, the flow path forming substrate 10 in which the pressure chamber 12 is formed is obtained. At this time, for example, an aqueous potassium hydroxide solution (KOH) or the like is used as an etching liquid for anisotropically etching the silicon single crystal substrate. At this time, the first layer 51 functions as a stopping layer that stops the anisotropic etching.

[0101] After the pressure chamber forming step S40, the recording head 2 is manufactured by appropriately performing steps such as bonding the protective substrate 30, the communication plate 15, etc. to the flow passage forming substrate 10 with an adhesive.

[0102] (Sample 1) One surface of a silicon single crystal substrate having a surface orientation (110) was thermally oxidized to form a first layer 51 made of silicon oxide and having a thickness of 1185 nm.

[0103] Next, a film made of zirconium was formed on the first layer 51 by sputtering, and the film was thermally oxidized at 900° C. to form the third layer 53 made of zirconium oxide and having a thickness of 645 nm. In this manner, diaphragm 50 consisting of first layer 51 and third layer 53 was manufactured.

[0104] (Sample 2) A film made of titanium was formed by sputtering on the first layer 51, which was the same as that of the above-mentioned sample 1, and the film was thermally oxidized to form a second layer 52 made of titanium oxide and having a thickness of 10 nm.

[0105] On this second layer 52, a third layer 53 similar to that of sample 1 was formed.

[0106] In this manner, diaphragm 50 consisting of first layer 51, second layer 52 and third layer 53 was manufactured.

[0107] (Samples 3-10) Other than changing the thickness of the second layer 52, the samples were the same as the above-mentioned sample 2. Samples 3 to 10 have second layer 52 thicknesses of 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 50 nm, and 60 nm, respectively.

[0108] (Test Example 1) Cross sections of Samples 1 to 10 were prepared using a focused ion beam (FIB), and the element distribution of the cross sections was analyzed by STEM-EDS. The results are shown in Figs. 7 to 9. Fig. 7 is a graph showing the element distribution of iron, Fig. 8 is a graph showing the element distribution of chromium, and Fig. 9 is a graph showing the element distribution of silicon.

[0109] In addition, cross sections of each of Samples 1, 4, 8, and 10 were observed by STEM (scanning transmission electron microscope). The results are shown in Figures 10 to 13. These results are also shown in Table 1 below.

[0110] [Table 1]

[0111] 7 to 9, in sample 1 not provided with second layer 52, impurities of iron, chromium, and silicon are locally distributed at the interface of third layer 53 on the first layer 51 side. In sample 1, iron compounds are locally accumulated on the first layer 51 side of third layer 53, as shown in FIG. In contrast, from the results shown in Figs. 7 to 9 and Figs. 11 to 13, in Samples 2 to 8, the positions where the concentrations of iron and chromium are highest are present in the second layer 52, suppressing localization of impurities in the third layer 53. Furthermore, in Samples 2 to 8, the diffusion of silicon in the first layer 51 to the third layer 53 can be suppressed more effectively than in Sample 1. Furthermore, in Samples 4 to 8, the diffusion of silicon to the third layer 53 can be suppressed more effectively than in Samples 2 and 3. Note that although gaps are observed in Sample 4, they are not continuously connected gaps but are scattered gaps, and therefore moisture intrusion can be suppressed. As shown in FIG. 12, particularly in sample 8, almost no iron impurity is found in the third layer 53. 7 to 9, in Samples 9 and 10, the diffusion of silicon into the third layer 53 can be suppressed, but iron and chromium are locally distributed near the interface of the third layer 53 on the second layer 52 side. In Sample 10, a gap is formed at the interface between the third layer 53 and the first layer 51, as shown in FIG. Therefore, in order to suppress the diffusion of all of the impurities, that is, iron, chromium, and silicon, into the third layer 53, the thickness T2 of the second layer 52 is preferably not less than 20 nm and not more than 40 nm.

[0112] In addition, the second layer 52 and the third layer 53 preferably have the same valence. Here, the second layer 52 and the third layer 53 have the same valence means that the difference X between the valence of the main constituent element of the second layer 52 and the valence of the main constituent element of the third layer 53 is within the range of -0.5≦X<+0.5. By making the valence of the second layer 52 and the third layer 53 the same in this way, the insulation of the entire vibration plate 50 is increased, so that the leakage current between the multiple active parts 310 of the piezoelectric actuator 300 can be suppressed. Therefore, the leakage current can be suppressed, and the decrease in displacement of the active parts 310 due to the leakage current can be reduced.

[0113] For example, when the third layer 53 is made of zirconium oxide (ZrO2) with a valence of +4, it is preferable to use, as a constituent element of the second layer 52, titanium or the like, which has the same valence of +4 and is stable.

[0114] Moreover, it is preferable that the second layer 52 and the third layer 53 have different valences. Here, the difference X between the valence of the main constituent element of the second layer 52 and the valence of the main constituent element of the third layer 53 is within the range of X<-0.5, +0.5≦X. In other words, when the constituent element of the second layer 52 has a valence of +4, it is preferable that the constituent element of the third layer 53 has a valence of less than +3.5 or a valence of +4.5 or more.

[0115] In this way, by making the valences of the second layer 52 and the third layer 53 different, the constituent elements of the second layer 52 are more likely to move toward the -Z direction side of the third layer 53. Therefore, when the active sections 310 are selectively driven, a leakage current is generated in the other active sections 310 that are not driven, causing a minute current to flow, thereby suppressing the variation in deterioration between the active sections 310 that are continuously driven and the other active sections 310 that are not driven. Therefore, the variation in the decrease in displacement of the multiple active sections 310 can be suppressed, and the variation in the ejection characteristics of the ink droplets can be suppressed, thereby improving the print quality.

[0116] For example, when the third layer 53 is made of zirconium oxide (ZrO2) with a valence of +4, the second layer 52 preferably uses, as a constituent element, chromium, aluminum, or the like, which has a different valence from that of the third layer 53.

[0117] (Sample 11) A first electrode 60, a piezoelectric layer 70, and a second electrode 80 were formed on the same diaphragm 50 as in Sample 1 and patterned to form a piezoelectric actuator 300 having the same shape as in the first embodiment.

[0118] Thereafter, the other surface of the silicon single crystal substrate was anisotropically etched using an aqueous potassium hydroxide solution (KOH) or the like as an etching solution, thereby forming a recess having the first layer 51 as its bottom surface.

[0119] (Sample 12) The thickness of the third layer 53 was 645 nm, but other than that, the thickness was the same as that of Sample 11.

[0120] (Sample 13) A film made of titanium was formed on the first layer 51 of the sample 11 by sputtering, and the film was thermally oxidized to form the second layer 52 made of titanium oxide and having a thickness of 40 nm.

[0121] Moreover, the thickness of the third layer 53 formed on the second layer 52 was set to 250 nm, and other than that, the thickness was the same as that of the above-mentioned sample 11.

[0122] (Sample 14) A film made of chromium was formed on the first layer 51 of the sample 11 by sputtering, and the film was thermally oxidized to form the second layer 52 made of chromium oxide and having a thickness of 40 nm.

[0123] Moreover, the thickness of the third layer 53 formed on the second layer 52 was set to 500 nm, and other than that, the thickness was the same as that of the above-mentioned sample 11.

[0124] (Sample 15) The thickness of the third layer 53 was set to 250 nm, but other than that, the thickness was the same as that of the above-mentioned sample 14.

[0125] (Test Example 2) A withstand voltage test, which will be described later, was carried out to obtain an average value for a plurality of active parts of the piezoelectric actuator of each of Samples 11 to 15. The results are shown in FIG.

[0126] In the withstand voltage test, the voltage applied between the first electrode 60 and the second electrode 80 is varied from 40V to 180V, and when the leakage current exceeds 1000nA, the voltage application is stopped. The voltage exceeding 1000nA is taken as the "withstand voltage."

[0127] [Table 2]

[0128] The results shown in Figure 14 and Table 2 indicate that by matching the valence of the third layer 53 and the second layer 52, as in sample 13, the insulation properties of the vibration plate 50 are improved, and leakage current between multiple active portions 310 can be suppressed.

[0129] Furthermore, by making the valence of the third layer 53 and the second layer 52 different as in samples 14 and 15, the leakage current can be increased to drive the other active portions 310 to produce micro-vibrations.

[0130] Moreover, it is preferable that the second layer 52 has layered impurities unevenly distributed on the third layer 53 side. The impurities are made of iron oxides. That is, the iron impurity in the second layer 52 is not uniformly distributed along the Z axis, but is unevenly distributed only on the third layer 53 side, so that the concentration of the iron impurity can be locally increased. It is preferable that the atomic concentration of iron on the third layer 53 side of such second layer 52 is 0.9% or more.

[0131] By having layered iron oxide on the third layer 53 side of the second layer 52 in this way, it is possible to increase the deformation of the crystal lattice in the direction perpendicular to the film thickness of the second layer 52, reduce the tensile stress, which is the internal stress of the entire second layer 52, and reduce the internal stress of the entire diaphragm 50. Therefore, it is possible to suppress the destruction of the diaphragm 50 when an external force is applied to the diaphragm 50 due to the deformation of the piezoelectric actuator 300. By distributing iron oxide in layers in the vicinity of the interface between the second layer 52 and the third layer 53, which is particularly susceptible to destruction, it is possible to increase the deformation of the crystal lattice of the second layer 52 near the interface and suppress stress concentration, and effectively suppress destruction near the interface, which is susceptible to destruction.

[0132] (Sample 16) The diaphragm 50 was the same as that of sample 1, except that the thickness of the third layer 53 was set to 400 nm.

[0133] (Sample 17) The diaphragm 50 was the same as that of sample 1, except that the thickness of the third layer 53 was 491 nm.

[0134] (Sample 18) The diaphragm 50 was the same as that of sample 1, except that the thickness of the third layer 53 was 645 nm.

[0135] (Sample 19) The diaphragm 50 was the same as that of sample 1, except that the thickness of the third layer 53 was 1280 nm.

[0136] (Sample 20) The diaphragm 50 was the same as that of sample 8, except that the thickness of the third layer 53 was set to 605 nm. That is, a configuration was provided in which the second layer 52 had a thickness of 40 nm. The thickness of the third layer in Samples 16–20 does not appear to correspond to the thicknesses in Figures 15–19.

[0137] (Test Example 3) Cross sections of Samples 16 to 20 were prepared using a focused ion beam (FIB) and observed by STEM. The results are shown in Figures 15 to 19. Sample 20 was also analyzed by STEM-EDS. The results are shown in Figure 20.

[0138] As shown in FIGS. 15 and 16, in the third layer 53 of Sample 16 and Sample 17, no granular iron oxide is formed.

[0139] As shown in FIGS. 17 and 18, granular iron oxide is locally formed on the first layer 51 side of the third layer 53 in each of Samples 18 and 19. In contrast, as shown in FIGS. 19 and 20, layered iron oxide is locally formed on the third layer 53 side of the second layer 52 of the sample 20.

[0140] From the above results, by providing the second layer 52, a layer of impurities, in this embodiment, iron oxide, can be formed on the third layer 53 side of the second layer 52. Moreover, in the above-mentioned sample 20, a layer of impurities made of iron oxide is also formed on the first layer 51 side of the second layer 52. This also makes it possible to increase the deformation of the crystal lattice of the second layer 52 near the interface on the first layer 51 side of the second layer 52, thereby suppressing stress concentration, and effectively suppressing fracture near the interface which is easily fractured.

[0141] (Test Example 4) For samples 16 to 20, the amount of warping of the silicon single crystal substrate was measured using a thin film stress measurement device (also known as a thin film stress measurement device), and the film stress of the third layer 53 was calculated from the amount of warping of the silicon single crystal substrate. The results are shown in Table 3 below.

[0142] [Table 3]

[0143] As shown in Table 3, in sample 20 in which iron oxide impurities are unevenly distributed in layers in second layer 52, the film stress, which becomes tensile stress, can be reduced compared to samples 16 to 19. Therefore, by unevenly distributing iron oxide impurities on the third layer 53 side of second layer 52 as in sample 20, it is possible to prevent diaphragm 50 from reaching its stress limit when an external force is applied to diaphragm 50, and thus to prevent diaphragm 50 from being broken.

[0144] As described above, the recording head 2, which is an example of the piezoelectric device of the present invention, includes a flow path forming substrate 10, a vibration plate 50, and a piezoelectric actuator 300, and the flow path forming substrate 10, the vibration plate 50, and the piezoelectric actuator 300 are laminated in this order in the −Z direction, which is a first direction. The vibration plate 50 also has a first layer 51 containing silicon as a constituent element, and a third layer 53 that is disposed between the first layer 51 and the piezoelectric actuator 300 and contains zirconium as a constituent element. The vibration plate 50 also has a second layer 52 that is disposed between the first layer 51 and the third layer 53 and contains at least one element selected from the group consisting of iron, metals other than silicon and zirconium, semimetals, and semiconductors as a constituent element. In the second layer 52 and the third layer 53, the position with the highest concentration of impurities other than the constituent elements of the second layer 52 and the third layer 53 is in the second layer 52, the position with the highest concentration of zirconium is in the third layer 53, and the position with the highest concentration of silicon is in the first layer 51.

[0145] In this way, the second layer 52 is the position with the highest concentration of impurities in the second layer 52 and the third layer 53, that is, the second layer 52 absorbs the impurities in the third layer 53, thereby reducing the impurities in the third layer 53. In particular, the impurities in the third layer 53 are prevented from being localized near the interface with the second layer 52, thereby preventing gaps from being formed at the interface between the third layer 53 and the second layer 52. This prevents the toughness of the vibration plate 50 from being reduced by the gaps, and prevents the vibration plate 50 from being broken when an external force is applied to the vibration plate 50 due to deformation of the piezoelectric actuator 300. In addition, moisture is prevented from entering the gap between the third layer 53 and the second layer 52, thereby preventing the zirconium in the third layer 53 from being embrittled by moisture, and prevents delamination between the third layer 53 and the layers above and below the third layer 53, and damage such as cracks in the third layer 53.

[0146] In addition, in the recording head 2 of this embodiment, the second layer 52 preferably contains at least one metal element selected from the group consisting of chromium, titanium, and aluminum. By using chromium, titanium, and aluminum as the constituent elements of the second layer 52, it is easy to form a film, and the adhesion between the second layer 52 and the first layer 51 and the third layer 53 can be improved. In addition, by providing the second layer 52 containing the above-mentioned metal elements as constituent elements, it is possible to suppress the diffusion of silicon from the first layer 51 side to the third layer 53. Therefore, it is possible to suppress the formation of a compound between silicon and zirconium, and to suppress the occurrence of a gap between the second layer 52 and the third layer 53 due to impurities derived from silicon. Therefore, it is possible to suppress the formation of a compound between silicon and zirconium, and to suppress the occurrence of a gap between the second layer 52 and the third layer 53 due to impurities derived from silicon.

[0147] In the recording head 2 of the present embodiment, the impurity is preferably at least one compound selected from the group consisting of iron, chromium, and silicon. By reducing the concentrations of iron and chromium contained in the third layer 53 and silicon of the first layer 51 in the third layer 53, it is possible to suppress the formation of gaps at the interface between the third layer 53 and the second layer 52.

[0148] In the recording head 2 of the present embodiment, the impurities are preferably compounds containing at least one of iron and chromium. This reduces the concentrations of iron and chromium in the third layer 53, and suppresses the formation of gaps at the interface between the third layer 53 and the second layer 52.

[0149] In the recording head 2 of this embodiment, the third layer 53 preferably has a higher impurity concentration than the first layer 51. By lowering the impurity concentration in the first layer 51, it is possible to suppress localization of impurities at the interface of the first layer 51 on the second layer 52 side, and suppress the formation of gaps at the interface. This makes it possible to suppress moisture penetration from the interface, suppress embrittlement of the second layer 52 and the first layer 51 due to moisture, and suppress delamination between the second layer 52 and the first layer 51, and damage such as cracks in the second layer 52 and the first layer 51.

[0150] In the recording head 2 of this embodiment, it is preferable that impurities are unevenly distributed in a layered manner at the interface of the second layer 52 on the third layer 53 side. By having layered impurities on the third layer 53 side of the second layer 52 in this way, it is possible to increase the deformation of the crystal lattice in the direction perpendicular to the film thickness of the second layer 52, reduce the tensile stress, which is the internal stress of the entire second layer 52, and reduce the internal stress of the entire vibration plate 50. Therefore, it is possible to prevent the vibration plate 50 from being destroyed when an external force is applied to the vibration plate 50 due to the deformation of the piezoelectric actuator 300. In particular, it is possible to suppress stress concentration at the interface between the second layer 52 and the third layer 53, and to suppress destruction at the interface.

[0151] In the recording head 2 of this embodiment, the impurities preferably include silicon, and the thickness of the second layer 52 in the first direction, i.e., the -Z direction, is preferably 10 nm or more and 60 nm or less. By setting the thickness of the second layer 52 to the above-mentioned range in this manner, it is possible to prevent silicon that has diffused from the first layer 51 to the second layer 52 from reaching the third layer 53, and to reduce the silicon concentration in the third layer 53.

[0152] In the recording head 2 of the present embodiment, the impurities preferably include iron or chromium, and the thickness of the second layer 52 in the first direction, i.e., the -Z direction, is preferably 10 nm or more and 40 nm or less. By making the second layer 52 have a thickness in the above-mentioned range, the impurities in the third layer 53 can be absorbed by the second layer 52, and the concentration of the impurities in the third layer 53 can be reduced.

[0153] In the recording head 2 of this embodiment, the second layer 52 and the third layer 53 preferably have different valences. With this, when the active sections 310 are selectively driven, a leakage current is generated in the other active sections 310 that are not driven, causing a minute current to flow, thereby suppressing the variation in deterioration between the active sections 310 that are continuously driven and the other active sections 310 that are not driven. Therefore, the variation in the displacement reduction of the multiple active sections 310 can be suppressed, and the variation in the ejection characteristics of the ink droplets can be suppressed, thereby improving the print quality.

[0154] In the recording head 2 of the present embodiment, the second layer 52 and the third layer 53 preferably have the same valence. This can improve the insulation of the diaphragm 50, suppress leakage current, and suppress the displacement reduction of the active portion 310.

[0155] In the recording head 2 of this embodiment, the first layer 51 preferably contains silicon oxide, and the third layer 53 preferably contains zirconium oxide. This allows the pressure chambers 12 to be formed with high precision by etching in the flow path forming substrate 10, using the first layer 51 as an etching stop layer. In addition, the crystal structure of the piezoelectric layer 70 can be controlled by the surface state of the third layer 53.

[0156] In the recording head 2 of the present embodiment, the second layer 52 preferably contains chromium oxide. In this manner, when the second layer 52 contains chromium oxide, the adhesion between the second layer 52 and the third layer 53 is improved, and the formation of voids at the interface can be suppressed.

[0157] In the recording head 2 of the present embodiment, the chromium oxide contained in the second layer 52 preferably has an amorphous structure. This can reduce the compressive stress, which is the internal stress of the second layer 52, and can reduce distortion occurring at the interface with the first layer 51 or the third layer 53.

[0158] In the recording head 2 of the present embodiment, the second layer 52 preferably contains titanium oxide. In this manner, when the second layer 52 contains titanium oxide, the adhesion between the second layer 52 and the third layer 53 is improved, and the formation of voids at the interface can be suppressed.

[0159] In the recording head 2 of the present embodiment, the titanium oxide contained in the second layer 52 preferably has a rutile structure. In this manner, when the titanium oxide contained in the second layer 52 has a rutile structure, the thermal stability of the second layer 52 can be improved compared to when the titanium oxide contained in the second layer 52 has a different crystal structure.

[0160] Moreover, an ink jet recording apparatus 1, which is an example of a liquid ejecting apparatus of the present invention, includes the above-mentioned recording head 2. It is possible to realize an ink jet recording apparatus 1 in which damage to the diaphragm 50 is suppressed and reliability is improved.

[0161] The recording head 2, which is an example of the piezoelectric device of the present invention, includes a flow path forming substrate 10, a vibration plate 50, and a piezoelectric actuator 300, and the flow path forming substrate 10, the vibration plate 50, and the piezoelectric actuator 300 are laminated in this order in the −Z direction, which is a first direction. The vibration plate 50 also has a first layer 51 containing silicon as a constituent element, and a third layer 53 that is disposed between the first layer 51 and the piezoelectric actuator 300 and contains zirconium as a constituent element. The vibration plate 50 also has a second layer 52 that is disposed between the first layer 51 and the third layer 53 and contains at least one element selected from the group consisting of iron, metals other than silicon and zirconium, semimetals, and semiconductors as a constituent element. In the second layer 52 and the third layer 53, the position where the concentration of impurities other than the constituent elements of the second layer 52 and the third layer 53 is the highest is in the second layer 52, the position where the zirconium concentration is the highest is in the third layer 53, and the position where the silicon concentration is the highest is in the first layer 51. The method for manufacturing such a recording head 2 includes a step of forming the first layer 51 on the flow path forming substrate 10. The method also includes a step of forming an element layer containing at least one selected from the group consisting of iron, silicon, and metals other than zirconium, semi-metals, and semiconductors on the first layer 51, and heating the element layer to form the second layer 52 made of an oxide. The method also includes a step of forming a zirconium layer containing zirconium on the second layer 52, and heating the zirconium layer to form the third layer 53 made of zirconium oxide.

[0162] (Other embodiments) Although each embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above.

[0163] For example, in each of the above-described embodiments, the first electrode 60 is an individual electrode of the piezoelectric actuator 300, and the second electrode 80 is a common electrode of the multiple piezoelectric actuators 300, but this is not particularly limited, and the first electrode 60 may be a common electrode of the multiple piezoelectric actuators 300, and the second electrode 80 may be an individual electrode of each piezoelectric actuator 300.

[0164] In addition, in the above-mentioned inkjet recording device 1, an example has been given in which the recording head 2 is mounted on a transport body 7 and moves back and forth along the X-axis, which is the main scanning direction, but this is not particularly limited to this, and the present invention can also be applied to, for example, a so-called line-type recording device in which the recording head 2 is fixed and printing is performed simply by moving a medium S, such as paper, along the Y-axis, which is the sub-scanning direction.

[0165] In the above embodiment, an ink jet recording head is used as an example of a liquid jet head, and an ink jet recording device is used as an example of a liquid jet device, but the present invention is intended for a wide range of liquid jet heads and liquid jet devices in general, and can of course be applied to liquid jet heads and liquid jet devices that jet liquids other than ink. Other liquid jet heads include, for example, various recording heads used in image recording devices such as printers, color material jet heads used in manufacturing color filters for liquid crystal displays, electrode material jet heads used in forming electrodes for organic EL displays, FEDs (field emission displays), and bioorganic material jet heads used in biochip manufacturing, and can also be applied to liquid jet devices equipped with such liquid jet heads.

[0166] Furthermore, the present invention is not limited to liquid jet heads such as ink jet recording heads, but can also be applied to ultrasonic devices, motors, pressure sensors, pyroelectric elements, ferroelectric elements, and other piezoelectric devices. Furthermore, completed products using these piezoelectric devices, such as liquid jetting devices using the liquid jetting heads described above, ultrasonic sensors using the ultrasonic devices described above, robots using the motors described above as a driving source, IR sensors using the pyroelectric elements described above, and ferroelectric memories using ferroelectric elements, are also included in the piezoelectric devices. [Explanation of symbols]

[0167] 1...inkjet recording device (liquid ejection device), 2...inkjet recording head (liquid ejection head), 3...liquid container, 4...transport mechanism, 4a...transport roller, 5...control unit, 6...movement mechanism, 7...transport body, 8...transport belt, 10...flow path forming substrate (substrate), 11...partition wall, 12...pressure chamber (recess), 15...communication plate, 16...nozzle communication passage, 17...first manifold portion, 18...second manifold portion, 19...supply communication passage, 20...nozzle plate, 20a...liquid ejection surface, 21...nozzle, 30...protective substrate, 31...holding portion, 32... Through hole, 40...case member, 41...recess, 42...third manifold portion, 43...connection port, 44...inlet port, 45...compliance substrate, 46...sealing film, 47...fixed substrate, 48...opening, 49...compliance portion, 50...diaphragm, 51...first layer, 52...second layer, 53...third layer, 60...first electrode, 70...piezoelectric layer, 71...recess, 80...second electrode, 91...individual lead electrode, 92...common lead electrode, 100...manifold, 120...wiring substrate, 121...drive circuit, 300...piezoelectric actuator, 310...active portion, S...medium

Claims

1. A substrate; A diaphragm; A piezoelectric actuator; The substrate, the vibration plate, and the piezoelectric actuator are laminated in this order in a first direction. And, The diaphragm is A first layer including silicon as a constituent element; A piezoelectric material is disposed between the first layer and the piezoelectric actuator, and contains zirconium as a constituent element. A third layer containing Umu; A metal oxide having iron, silicon and zirconium as constituent elements is disposed between the first layer and the third layer. The second metal element includes at least one selected from the group consisting of metals other than aluminum, semimetals, and semiconductors. Two layers, having In the second layer and the third layer, the second layer has a highest concentration of impurities; the highest zirconium concentration is in the third layer; The location of the highest silicon concentration is in the first layer. A piezoelectric device characterized by:

2. The second layer is at least one selected from the group consisting of chromium, titanium and aluminum.

2. The piezoelectric device according to claim 1, further comprising one metal element.

3. The impurities are at least one element selected from the group consisting of iron, chromium, and silicon. It is a mixture 3. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

4. The impurities are compounds containing at least one of iron and chromium.

4. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

5. The third layer has a higher impurity concentration than the first layer.

5. The piezoelectric device according to claim 4.

6. The impurities are unevenly distributed in a layer shape at the interface of the second layer on the third layer side.

6. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

7. The impurity includes silicon, and the thickness of the second layer in the first direction is 10 nm or more and 0 nm or less 7. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

8. The impurities include iron or chromium, and the thickness of the second layer in the first direction is 10 nm or more and 40 nm or less 7. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

9. The difference between the valence of the main constituent element of the second layer and the valence of the main constituent element of the third layer is , less than −0.5 or greater than or equal to 0.5; 9. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

10. The difference between the valence of the main constituent element of the second layer and the valence of the main constituent element of the third layer is , -0.5 or more and less than 0.5; 9. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

11. the first layer comprises silicon oxide; The third layer includes zirconium oxide.

11. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

12. The second layer includes chromium oxide.

12. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

13. The chromium oxide contained in the second layer has an amorphous structure.

13. The piezoelectric device according to claim 12.

14. The second layer includes titanium oxide.

12. The piezoelectric device according to claim 1, wherein the piezoelectric element is a piezoelectric material.

15. The titanium oxide contained in the second layer has a rutile structure.

15. The piezoelectric device according to claim 14.

16. A piezoelectric actuator; a vibration plate that vibrates when driven by the piezoelectric actuator; a flow path forming substrate provided with a pressure chamber that applies pressure to a liquid by vibration of the vibration plate; Equipped with The flow path forming substrate, the vibration plate, and the piezoelectric actuator are rotated in this order in a first direction. It is layered, The diaphragm is A first layer including silicon as a constituent element; A piezoelectric material is disposed between the first layer and the piezoelectric actuator, and contains zirconium as a constituent element. A third layer containing Umu; A metal oxide having iron, silicon and zirconium as constituent elements is disposed between the first layer and the third layer. At least one selected from the group consisting of metals other than nium, metalloids, and semiconductors. A second layer; and having In the second layer and the third layer, the second layer has a highest concentration of impurities; the highest zirconium concentration is in the third layer; The location of the highest silicon concentration is in the first layer. A liquid jet head comprising:

17. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 16.

18. A substrate; A diaphragm; A piezoelectric actuator; The substrate, the vibration plate, and the piezoelectric actuator are laminated in this order in a first direction. And, The diaphragm is A first layer including silicon as a constituent element; A piezoelectric material is disposed between the first layer and the piezoelectric actuator, and contains zirconium as a constituent element. A third layer containing Umu; A metal oxide having iron, silicon and zirconium as constituent elements is disposed between the first layer and the third layer. At least one selected from the group consisting of metals other than nium, metalloids, and semiconductors. A second layer; and having In the second layer and the third layer, the second layer has a highest concentration of impurities; the highest zirconium concentration is in the third layer; 1. A method for manufacturing a piezoelectric device, comprising the steps of: forming the first layer on the substrate; The first layer is provided with a metal, semimetal, and other elements other than iron, silicon, and zirconium. forming an element layer including at least one selected from the group consisting of a semiconductor and a heating to form the second layer comprised of an oxide; A zirconium layer containing zirconium is formed on the second layer, and the zirconium layer is heated. heating to form the third layer comprised of zirconium oxide; 13. A method for manufacturing a piezoelectric device comprising the steps of:

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