Piezoelectric element, liquid ejection head, and printer

Abstract

The invention provides a piezoelectric element, a liquid ejection head, and a printer, which can improve moisture resistance while ensuring insulating properties of a piezoelectric layer. The piezoelectric element includes: a first electrode provided above the substrate; a piezoelectric layer provided above the first electrode; a second electrode provided above the piezoelectric body layer; and a moisture-resistant layer that covers at least a portion of the piezoelectric layer, and when the piezoelectric layer is subjected to secondary ion mass spectrometry, the hydrogen concentration calculated from the integrated intensity within the range of 50 nm to 300 nm inclusive from the surface of the piezoelectric layer is 1.50 * 1015 atom / cm2 or less.

Description

Technical Field

[0001] The present invention relates to a piezoelectric element, a liquid ejection head, and a printer. Background Art

[0002] A piezoelectric element used in a liquid ejection head of an inkjet printer or the like is composed of, for example, a piezoelectric layer made of a piezoelectric material having an electromechanical conversion function, sandwiched between two electrodes.

[0003] For example, Patent Document 1 describes a piezoelectric thin-film element including: a lower electrode film; a piezoelectric thin film formed into the shape of the lower electrode film and containing potassium, sodium, and niobium; and an upper electrode film formed on the piezoelectric thin film.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-65018

[0005] In the piezoelectric thin-film element described above, it is required to improve moisture resistance while ensuring the insulation properties of the piezoelectric thin film. Summary of the Invention

[0006] One embodiment of the piezoelectric element according to the present invention is:

[0007] The method comprises: a first electrode, arranged above the substrate;

[0008] a piezoelectric layer disposed above the first electrode;

[0009] a second electrode disposed above the piezoelectric layer; and

[0010] a moisture-resistant layer covering at least a portion of the piezoelectric layer;

[0011] When the piezoelectric layer was subjected to secondary ion mass spectrometry, the hydrogen concentration calculated from the integrated intensity within a range of 50 nm to 300 nm from the surface of the piezoelectric layer was 1.50×10 15 atom / cm 2 the following.

[0012] One embodiment of the liquid ejection head according to the present invention is:

[0013] comprising: the piezoelectric element; and

[0014] a nozzle plate formed with nozzle holes,

[0015] The substrate includes a flow path forming substrate having a pressure generating chamber whose volume is changed by the piezoelectric element.

[0016] The nozzle hole is in communication with the pressure generating chamber.

[0017] One embodiment of the printer according to the present invention is:

[0018] comprising: the liquid ejection head;

[0019] a transport mechanism for moving the recording medium relative to the liquid ejection head; and

[0020] The control unit controls the liquid ejection head and the conveying mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a plan view schematically showing the piezoelectric element according to this embodiment.

[0022] Figure 2 It is a cross-sectional view schematically showing the piezoelectric element according to this embodiment.

[0023] Figure 3 It is a cross-sectional view schematically showing the piezoelectric element according to this embodiment.

[0024] Figure 4 It is a cross-sectional view schematically showing the manufacturing process of the piezoelectric element according to the present embodiment.

[0025] Figure 5 It is a cross-sectional view schematically showing the manufacturing process of the piezoelectric element according to the present embodiment.

[0026] Figure 6 It is a cross-sectional view schematically showing the manufacturing process of the piezoelectric element according to the present embodiment.

[0027] Figure 7 1 is a cross-sectional view schematically showing a piezoelectric element according to a reference example.

[0028] Figure 8 1 is a cross-sectional view schematically showing a piezoelectric element according to a reference example.

[0029] Figure 9 1 is a cross-sectional view schematically showing a piezoelectric element according to a reference example.

[0030] Figure 10 It is a cross-sectional view schematically showing the piezoelectric element according to this embodiment.

[0031] Figure 11 It is an exploded perspective view schematically showing the liquid ejecting head according to the present embodiment.

[0032] Figure 12 It is a perspective view schematically showing a printer according to this embodiment.

[0033] Figure 13This is a table showing the results of SIMS and leakage current measurement in Experimental Examples 1 to 3.

[0034] Figure 14 It is a graph showing the results of SIMS of Experimental Examples 1 to 3.

[0035] Figure 15 It is a graph showing the results of leakage current measurement in Experimental Examples 1 to 3.

[0036] Figure 16 This is a table showing the SIMS results of Experimental Examples 4 and 5.

[0037] Figure 17 It is a graph showing the results of SIMS in Experimental Examples 4 and 5.

[0038] Figure 18 It is a graph showing the results of SIMS of Experimental Examples 6 to 8.

[0039] Figure 19 This is a table showing the experimental results of Experimental Examples 9 to 16.

[0040] Figure 20 It is a graph showing the experimental results of Experimental Examples 9 to 16.

[0041] Description of Reference Numerals

[0042] 2…substrate; 10…first electrode; 20…piezoelectric layer; 22…surface; 30…second electrode; 40…third electrode; 50…moisture-resistant layer; 52…first contact hole; 54…surface; 60…organic insulating layer; 62…second contact hole; 70…wiring; 100…piezoelectric element; 200…liquid ejection head; 210…flow path forming substrate; 211…pressure generating chamber; 212…partition wall; 213…first communication path; 214…second communication path; 215…third communication path; 216…manifold; 217…supply path; 220…nozzle plate; 222…nozzle hole; 230…vibration plate; 232…silicon oxide layer; 234…zirconia layer; 240…protective substrate; 242, 244…through hole; 246…opening; 250…circuit substrate; 260…flexible substrate; 262…sealing layer; 264…fixing plate; 266…through hole; 300…printer; 310…print head assembly; 312, 314…cassette; 316…slide; 320…device body; 322…slide shaft; 330…drive motor; 332…timing belt; 340…conveyor roller; 350…printer controller; 1002…substrate; 1010…first electrode; 1020…piezoelectric layer; 1030…second electrode; 1040…third electrode; 1050…moisture-resistant layer; 1052…contact hole. DETAILED DESCRIPTION

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail using the accompanying drawings. Furthermore, the embodiments described below are not intended to unduly limit the scope of the present invention as described in the claims. Furthermore, all the components described below are not intended to be essential components of the present invention.

[0044] 1. Piezoelectric elements

[0045] 1.1. Composition

[0046] First, a piezoelectric element according to this embodiment will be described with reference to the drawings. Figure 1 1 is a plan view schematically showing the piezoelectric element 100 according to the present embodiment. Figure 2 The piezoelectric element 100 according to this embodiment is schematically shown. Figure 1 Cross-sectional view along line II-II. Figure 3 The piezoelectric element 100 according to this embodiment is schematically shown. Figure 1 In addition, in the III-III line cross-sectional view Figures 1 to 3 , an X-axis, a Y-axis, and a Z-axis are shown as three axes that are orthogonal to each other.

[0047] like Figures 1 to 3 As shown, the piezoelectric element 100 includes, for example, a first electrode 10, a piezoelectric layer 20, a second electrode 30, a third electrode 40, a moisture-resistant layer 50, an organic insulating layer 60, and a wiring 70. Figure 1 In the figure, members other than the substrate 2, the first electrode 10, the piezoelectric layer 20, the third electrode 40, and the wiring 70 are omitted from illustration.

[0048] The piezoelectric element 100 is provided on the substrate 2. Figure 1 In the example shown, a plurality of piezoelectric elements 100 are provided. The number of piezoelectric elements 100 is not particularly limited. Figure 1 In the example shown, a plurality of piezoelectric elements 100 are arranged in the X-axis direction.

[0049] The substrate 2 is a flat plate formed of, for example, a semiconductor, an insulator, or the like. The substrate 2 may be a single layer or a laminated structure comprising multiple layers. The substrate 2 may have any internal structure as long as its upper surface is flat, and may have a structure with a space formed therein.

[0050] The substrate 2 may include a vibration plate that is deformed by the operation of the piezoelectric layer 20. The vibration plate is, for example, a silicon oxide layer, a zirconium oxide layer, or a laminated body in which a zirconium oxide layer is provided on a silicon oxide layer.

[0051] like Figure 2As shown, the first electrode 10 is provided above the substrate 2. In the example shown in the figure, the first electrode 10 is provided on the substrate 2. In the description of the present invention, the phrase "above" is used, for example, as "a specific component (hereinafter referred to as "A") is provided above another specific component (hereinafter referred to as "B")." This includes both cases where A is provided directly on B and cases where A is provided on B via another component.

[0052] The first electrode 10 is provided between the substrate 2 and the piezoelectric layer 20. The first electrode 10 is, for example, layered. The thickness of the first electrode 10 is, for example, not less than 5 nm and not more than 500 nm, preferably not less than 10 nm and not more than 300 nm. The first electrodes 10 are connected to each other in adjacent piezoelectric elements 100. The first electrode 10 constitutes a common electrode in the plurality of piezoelectric elements 100.

[0053] The first electrode 10 may be a titanium layer, a platinum layer, an iridium layer, or the like. The first electrode 10 may be formed by stacking the titanium layer, the platinum layer, and the iridium layer in this order, starting from the substrate 2 side. The titanium layer, for example, improves adhesion between the substrate 2 and the platinum layer. The first electrode 10 is an electrode used to apply a voltage to the piezoelectric layer 20.

[0054] The piezoelectric layer 20 is provided above the first electrode 10. In the illustrated example, the piezoelectric layer 20 is provided on the first electrode 10. The piezoelectric layer 20 is provided between the first electrode 10 and the second electrode 30. The thickness of the piezoelectric layer 20 is, for example, not less than 100 nm and not more than 3000 nm, preferably not less than 200 nm and not more than 2500 nm. The piezoelectric layer 20 deforms when a voltage is applied between the first electrode 10 and the third electrode 40.

[0055] The piezoelectric layer 20 includes, for example, a composite oxide having a perovskite structure containing potassium (K), sodium (Na), and niobium (Nb). The piezoelectric layer 20 is, for example, a potassium sodium niobate ((K, Na)NbO3:KNN) layer. The composition of the perovskite structure of the piezoelectric layer 20 may be a stoichiometric composition or may be different from the stoichiometric composition. The piezoelectric layer 20 may also be a KNN layer to which an additive is added. Examples of additives include lithium (Li), manganese (Mn), copper (Cu), or oxides thereof. The content of the additive in the piezoelectric layer 20 is, for example, less than 10 mol%, preferably less than 5 mol%.

[0056] The material of the piezoelectric layer 20 is not limited to KNN. The piezoelectric layer 20 may include a perovskite-type composite oxide containing lead (Pb), zirconium (Zr), and titanium (Ti). Alternatively, the material of the piezoelectric layer 20 may be lead zirconate titanate (Pb(Zr,Ti)O3:PZT).

[0057] The second electrode 30 is provided above the piezoelectric layer 20. In the illustrated example, the second electrode 30 is provided on the piezoelectric layer 20. The second electrode 30 is provided between the piezoelectric layer 20 and the third electrode 40. The second electrode 30 has, for example, a layered shape. The thickness of the second electrode 30 is, for example, smaller than the thickness of the third electrode 40. The thickness of the second electrode 30 is, for example, not less than 1 nm and not more than 100 nm, and preferably not less than 5 nm and not more than 50 nm.

[0058] The second electrode 30 is made of, for example, a metal oxide. The second electrode 30 is conductive and is made of, for example, iridium oxide (IrO 2 ) or ruthenium oxide (RuO 2 ).

[0059] The third electrode 40 is disposed above the second electrode 30. In the illustrated example, the third electrode 40 is disposed on the second electrode 30. The third electrode 40 is electrically connected to the second electrode 30. The third electrode 40 has, for example, a layered shape. The thickness of the third electrode 40 is, for example, from 5 nm to 500 nm, preferably from 10 nm to 300 nm. The third electrodes 40 are isolated from each other in adjacent piezoelectric elements 100. The third electrode 40 constitutes an independent electrode in the plurality of piezoelectric elements 100.

[0060] The resistivity of the third electrode 40 is lower than that of the second electrode 30. The material of the third electrode 40 is, for example, a precious metal. The third electrode 40 is, for example, a platinum layer or an iridium layer. The third electrode 40 may also be an electrode formed by stacking multiple layers of the above-mentioned examples. The second electrode 30 and the third electrode 40 are other electrodes for applying a voltage to the piezoelectric layer 20.

[0061] The moisture-resistant layer 50 covers at least a portion of the piezoelectric layer 20. In the illustrated example, the moisture-resistant layer 50 covers the side surfaces of the piezoelectric layer 20. Furthermore, the moisture-resistant layer 50 is provided on the second electrode 30 and the first electrode 10. A first contact hole 52 is formed in the moisture-resistant layer 50. The first contact hole 52 exposes the second electrode 30. The third electrode 40 is provided in the first contact hole 52. The piezoelectric element 100 includes a stacked portion 102 in which the second electrode 30, the moisture-resistant layer 50, and the third electrode 40 are stacked in this order from the piezoelectric layer 20 side. In the stacked portion 102, the moisture-resistant layer 50 is provided between the second electrode 30 and the third electrode 40.

[0062] The thickness of the moisture-resistant layer 50 is, for example, 5 nm to 100 nm, preferably 10 nm to 70 nm. For example, the thickness of the moisture-resistant layer 50 and the thickness of each layer included in the piezoelectric element 100 can be measured using a scanning electron microscope (SEM).

[0063] The material of the moisture-resistant layer 50 is, for example, a metal oxide. Examples of the moisture-resistant layer 50 include a hafnium oxide (HfO2) layer, a thallium oxide (Ta2O5) layer, a niobium oxide (Nb2O5) layer, a zirconium oxide (ZrO2) layer, or a titanium oxide (TiO2) layer. The moisture-resistant layer 50 has the function of reducing the amount of water that enters the piezoelectric layer 20.

[0064] like Figure 3 As shown, an organic insulating layer 60 is disposed on the third electrode 40 and the moisture-resistant layer 50. The organic insulating layer 60 covers the moisture-resistant layer 50. A second contact hole 62 is formed in the organic insulating layer 60. The second contact hole 62 exposes the third electrode 40. The material of the organic insulating layer 60 is, for example, a resist. The material of the organic insulating layer 60 can also be a permanent resist.

[0065] The wiring 70 is provided on the moisture-resistant layer 50, the organic insulating layer 60, and the second contact hole 62. The wiring 70 is electrically connected to the third electrode 40. The material of the wiring 70 is, for example, gold.

[0066] 1.2.SIMS

[0067] When the piezoelectric layer 20 was subjected to secondary ion mass spectrometry (SIMS), the hydrogen concentration calculated from the integrated intensity within a range of 50 nm to 300 nm from the surface 22 of the piezoelectric layer 20 (hereinafter also referred to as "integrated hydrogen concentration") was 1.50×10 15 atom / cm 2 Below, preferably 1.00×10 15 atom / cm 2 Below, more preferably 9.75×10 14 atom / cm 2 The integrated hydrogen concentration in the piezoelectric layer 20 is, for example, 1.00×10 14 atom / cm 2 More than, preferably 5.00×10 14 atom / cm 2 More than 8.72×10 14 atom / cm 2 above.

[0068] The surface 22 of the piezoelectric layer 20 is the upper surface of the piezoelectric layer 20 and is the surface of the piezoelectric layer 20 on the second electrode 30 side. Figure 2In the example shown, surface 22 is in contact with second electrode 30. In SIMS, an ion beam is irradiated onto piezoelectric layer 20, and the integrated hydrogen concentration is calculated based on the detected intensity. SIMS can analyze the thickness direction of piezoelectric layer 20. The following describes the method for converting the intensity detected by SIMS into concentration.

[0069] (1) Prepare a reference object having the same structure as the object for which concentration conversion is to be performed.

[0070] (2) Ion implantation of an element of desired predetermined concentration into the prepared reference object is performed.

[0071] (3) Based on known information about the object (thickness, composition, density), simulations are performed in advance to determine the ion implantation conditions (acceleration voltage, current, and treatment time) so that the maximum concentration is achieved at a specified location in the thickness direction. For example, if the location in the thickness direction is too close to the surface, it is easily affected by contaminants, while if it is too deep, ions may be injected into the layer below the target layer unnecessarily.

[0072] (4) Ion implantation is performed on the reference object under predetermined conditions, and the dose (ion implantation amount) is calculated based on the current value, processing time, and ion beam irradiation area at that time.

[0073] (5) Measure the reference object (with or without ion implantation) using the same SIMS apparatus and measurement conditions as those used to measure the object for which the concentration conversion is desired.

[0074] (6) Subtract the peak intensity of the reference object without ion implantation from the peak intensity of the reference object with ion implantation, and calculate the integral value of the parent phase range. The relationship between this integral value and the dose is the relative sensitivity factor (RSF).

[0075] (7) Using the obtained relative sensitivity coefficient, the entire secondary ion intensity distribution of the measurement results of the object for which concentration conversion is desired is converted into concentration.

[0076] The above-described method enables conversion of the intensity detected by SIMS into the concentration.

[0077] When SIMS is performed on the moisture-resistant layer 50 after the piezoelectric element 100 is exposed to an atmosphere at a temperature of 80°C and a humidity of 100% for 24 hours, for example, the hydrogen concentration within a range of 22 nm or less from the surface 54 of the moisture-resistant layer 50 is 1 / 10 of that at the surface 54 of the moisture-resistant layer 50. In the illustrated example, the surface 54 of the moisture-resistant layer 50 is the upper surface of the moisture-resistant layer 50.

[0078] Manufacturing method

[0079] Next, a method for manufacturing the piezoelectric element 100 according to this embodiment will be described with reference to the drawings. Figures 4 to 6 2 is a cross-sectional view schematically showing a manufacturing process of the piezoelectric element 100 according to the present embodiment.

[0080] like Figure 4 As shown, a substrate 2 is prepared. Specifically, a silicon oxide layer is formed by thermally oxidizing a silicon substrate. Next, a zirconium layer is formed on the silicon oxide layer by sputtering or the like, and this zirconium layer is thermally oxidized to form a zirconium oxide layer. Through the above steps, the substrate 2 can be prepared.

[0081] Next, the first electrode 10 is formed on the substrate 2. The first electrode 10 is formed by, for example, sputtering or vacuum deposition.

[0082] Next, a piezoelectric layer 20 is formed on the first electrode 10. The piezoelectric layer 20 can be formed using a liquid phase method such as a sol-gel method or a metal organic deposition (MOD) method, or a vapor phase method such as sputtering. The following describes the case where the piezoelectric layer 20, which serves as a KNN layer, is formed using a liquid phase method.

[0083] First, a metal complex containing potassium, a metal complex containing sodium, and a metal complex containing niobium are dissolved or dispersed in an organic solvent to prepare a precursor solution. Examples of the metal complex containing potassium include potassium 2-ethylhexanoate. Examples of the metal complex containing sodium include sodium 2-ethylhexanoate. Examples of the metal complex containing niobium include niobium 2-ethylhexanoate. Examples of the organic solvent include 2-ethylhexanoic acid, decane, or a mixed solvent thereof.

[0084] Next, the prepared precursor solution is applied to the first electrode 10 using a spin coating method or the like to form a precursor layer. The precursor layer is then heated, for example, at a temperature between 130°C and 250°C and dried for a predetermined time. Furthermore, the dried precursor layer is heated, for example, at a temperature between 300°C and 450°C and held for a predetermined time to degrease it. The degreased precursor layer is then sintered to crystallize it.

[0085] The above steps can form a crystal layer. Then, the series of steps from applying the precursor solution to firing the precursor layer is repeated multiple times. In this way, the piezoelectric layer 20 composed of multiple crystal layers can be formed.

[0086] In the step of forming the piezoelectric layer 20 , a heating device used for drying and degreasing the precursor layer is, for example, a hot plate. A heating device used for firing the precursor layer is, for example, an infrared lamp annealing device using rapid thermal annealing (RTA).

[0087] Next, the second electrode 30 is formed on the piezoelectric layer 20. The second electrode 30 is formed by, for example, a chemical vapor deposition method (CVD) or a sputtering method.

[0088] like Figure 5 As shown, the second electrode 30 and the piezoelectric layer 20 are patterned. Patterning is performed by, for example, photolithography and etching. For etching, ion milling is used, for example.

[0089] like Figure 6 As shown, a moisture-resistant layer 50 is formed to cover the piezoelectric layer 20 and the second electrode 30. The moisture-resistant layer 50 is formed, for example, by atomic layer deposition (ALD). It is known that in the ALD method, when forming a film at around 85°C, a dense layer can be formed when water (H2O) is used as an oxidant, and when forming a film at around 150°C, a dense layer can be formed when ozone (O3) is used as an oxidant. The moisture-resistant layer 50 may be a layer formed by the ALD method using H2O as an oxidant, or a layer formed by the ALD method using O3 as an oxidant.

[0090] Next, the moisture-resistant layer 50 is patterned to form a first contact hole 52. The second electrode 30 is exposed through the first contact hole 52. The patterning is performed by, for example, photolithography and etching.

[0091] like Figure 2 As shown, the third electrode 40 is formed on the second electrode 30 and the moisture-resistant layer 50. The third electrode 40 is formed by, for example, sputtering, vacuum evaporation, etc. Next, the third electrode 40 is patterned. Patterning is performed by, for example, photolithography and etching.

[0092] like Figure 3 As shown, an organic insulating layer 60 having a second contact hole 62 is formed on the third electrode 40 and the moisture-resistant layer 50. The organic insulating layer 60 is formed by performing film formation by spin coating, drying, exposure, and development, followed by curing by heat treatment. The heat treatment can be performed in air or in a vacuum.

[0093] Next, the wiring 70 is formed on the third electrode 40, the moisture-resistant layer 50, and the organic insulating layer 60. The wiring 70 is formed by, for example, film formation by sputtering and patterning by photolithography and etching.

[0094] Through the above steps, the piezoelectric element 100 can be manufactured.

[0095] 1.4. Effects

[0096] The piezoelectric element 100 includes a first electrode 10 disposed on a substrate 2; a piezoelectric layer 20 disposed on the first electrode 10; a second electrode 30 disposed on the piezoelectric layer 20; and a moisture-resistant layer 50 covering at least a portion of the piezoelectric layer 20. When secondary ion mass spectrometry was performed on the piezoelectric layer 20, the integrated hydrogen concentration calculated from the integrated intensity within a range of 50 nm to 300 nm from the surface 22 of the piezoelectric layer 20 was 1.50×10 15 atom / cm 2 the following.

[0097] Therefore, in the piezoelectric element 100, the integrated hydrogen concentration in the piezoelectric layer is greater than 1.50×10 15 atom / cm 2 Compared to the case where the piezoelectric layer 20 has a high integrated hydrogen concentration, the insulation properties of the piezoelectric layer 20 can be improved. When the integrated hydrogen concentration of the piezoelectric layer is high, part of the composite oxide forming the piezoelectric layer is reduced, the insulation properties are deteriorated, and the leakage current increases. Furthermore, in the piezoelectric element 100, the moisture-resistant layer 50 can suppress the intrusion of moisture into the piezoelectric layer 20.

[0098] Here, Figure 7 1 is a schematic cross-sectional view of a piezoelectric element according to a reference example. The piezoelectric element according to the reference example is constructed by sequentially forming a first electrode 1010, a piezoelectric layer 1020, a second electrode 1030, and a third electrode 1040 on a substrate 1002, patterning each layer, and then forming a moisture-resistant layer 1050.

[0099] When the moisture-resistant layer 1050 is formed by an ALD method with a film forming temperature of 150° C. and O 3 as an oxidizing material, as shown in FIG. Figure 7 As shown, hydrogen (H) introduced into the third electrode 40 during the manufacturing process diffuses into the piezoelectric layer 1020 depending on the temperature during the formation of the moisture-resistant layer 1050. As a result, the hydrogen concentration in the piezoelectric layer 1020 increases, and the leakage current increases.

[0100] When the moisture-resistant layer 1050 is formed by the ALD method with a film forming temperature of 85° C. and H 2 O as an oxidizing material, as shown in FIG. Figure 8As shown, when the moisture-resistant layer 1050 is formed, hydrogen (H) from H2O of the oxidizing material diffuses into the piezoelectric layer 1020. As a result, the hydrogen concentration of the piezoelectric layer 1020 increases, and the leakage current increases.

[0101] In this way, Figure 7 and Figure 8 In the example shown, the formation of the moisture-resistant layer 1050 increases the hydrogen concentration in the piezoelectric layer 1020 and deteriorates the insulation properties.

[0102] On the other hand, Figure 9 As shown, when the moisture-resistant layer 1050 covering the piezoelectric layer 1020 is formed without forming the second electrode 1030 and the third electrode 1040 is formed after forming the contact hole 1052, the piezoelectric layer 1020 is etched with damage D or surface contamination during the formation of the contact hole 1052, thereby deteriorating insulation.

[0103] As described above, in the piezoelectric element 100, even if the moisture-resistant layer 50 is provided, the integrated hydrogen concentration of the piezoelectric layer 20 is as low as 1.50×10 15 atom / cm 2 Therefore, in the piezoelectric element 100 , it is possible to improve moisture resistance while ensuring the insulation properties of the piezoelectric layer 20 . As a result, it is possible to realize the piezoelectric element 100 with low power consumption, high efficiency, and high reliability.

[0104] In the piezoelectric element 100, the integrated hydrogen concentration of the piezoelectric layer 20 is preferably 1.00×10 15 atom / cm 2 Below, more preferably 9.75×10 14 atom / cm 2 Therefore, in the piezoelectric element 100 , the insulation properties of the piezoelectric layer 20 can be further improved.

[0105] The piezoelectric element 100 includes a third electrode 40 disposed above and electrically connected to the second electrode 30. The second electrode 30 is made of a metal oxide, and the third electrode 40 is made of a noble metal. Therefore, in the piezoelectric element 100, the resistance of the electrode structure composed of the second electrode 30 and the third electrode 40 can be reduced compared to a case where the third electrode is not provided.

[0106] The piezoelectric element 100 includes a stacked portion 102 in which the second electrode 30, the moisture-resistant layer 50, and the third electrode 40 are stacked in this order from the piezoelectric layer 20 side. Thus, the piezoelectric element 100 is formed in this order from the piezoelectric layer 20 side. Therefore, the second electrode 30 can reduce etching damage or contamination of the piezoelectric layer 20 when forming the first contact hole 52. This can also prevent the Schottky barrier at the interface between the piezoelectric layer 20 and the electrodes from decreasing.

[0107] In the piezoelectric element 100, the moisture-resistant layer 50 is formed using ALD using O₃ as an oxidizing agent. In the piezoelectric element 100, even when O₃ is used as the oxidizing agent at a film formation temperature of approximately 150°C, the moisture-resistant layer 50 is formed before the third electrode 40 is formed. This prevents hydrogen introduced into the third electrode 40 from diffusing into the piezoelectric layer 20 during the formation of the moisture-resistant layer 50. Furthermore, since the oxidizing agent does not contain hydrogen, reduction of the piezoelectric layer 20 by the oxidizing agent can be suppressed.

[0108] In the piezoelectric element 100 , the moisture-resistant layer 50 is formed by ALD using H 2 O as an oxidant. Therefore, in the piezoelectric element 100 , a dense moisture-resistant layer 50 can be formed even at a film formation temperature of approximately 85° C.

[0109] In the piezoelectric element 100, when SIMS was performed on the moisture-resistant layer 50 after exposure to an atmosphere at a temperature of 80°C and a humidity of 100% for 24 hours, the hydrogen concentration within a range of 22 nm or less from the surface 54 of the moisture-resistant layer 50 was 1 / 10 of that at the surface 54 of the moisture-resistant layer 50. Therefore, the moisture resistance of the piezoelectric element 100 can be improved.

[0110] In the piezoelectric element 100 , the piezoelectric layer 20 includes a composite oxide having a perovskite structure containing potassium, sodium, and niobium. Since the piezoelectric layer 20 does not contain lead, the piezoelectric element 100 is environmentally friendly.

[0111] In addition, in the above description, the example in which the first electrode 10 is a common electrode and the third electrode 40 is an independent electrode is described, but the first electrode 10 may be an independent electrode and the third electrode 40 may be a common electrode. Figure 10 It is a cross-sectional view schematically showing an example in which the first electrode 10 is an independent electrode and the third electrode 40 is a common electrode.

[0112] 2. Liquid ejection head

[0113] Next, the liquid ejection head according to the present embodiment will be described with reference to the drawings. Figure 11It is an exploded perspective view schematically showing the liquid ejecting head 200 according to the present embodiment.

[0114] like Figure 11 As shown, the liquid ejection head 200 includes, for example, a substrate 2, a piezoelectric element 100, a nozzle plate 220, a protective substrate 240, a circuit substrate 250, and a flexible substrate 260. The substrate 2 includes, for example, a flow path forming substrate 210 and a vibration plate 230.

[0115] The flow channel forming substrate 210 is, for example, a silicon substrate. A pressure generating chamber 211 is formed on the flow channel forming substrate 210. The pressure generating chamber 211 is partitioned by a plurality of partition walls 212. The volume of the pressure generating chamber 211 is changed by the piezoelectric element 100.

[0116] A first communication channel 213 and a second communication channel 214 are formed at the +Y-axis end of the pressure generating chamber 211 on the flow channel forming substrate 210. The first communication channel 213 is configured so that its opening area is reduced by narrowing the +Y-axis end of the pressure generating chamber 211 in the X-axis direction. The size of the second communication channel 214 in the X-axis direction is, for example, the same as the size of the pressure generating chamber 211 in the X-axis direction. A third communication channel 215 is formed in the +Y-axis direction of the second communication channel 214, connecting to the plurality of second communication channels 214. The third communication channel 215 forms part of a manifold 216. The manifold 216 serves as a common liquid chamber for each pressure generating chamber 211. Thus, the flow channel forming substrate 210 includes a supply channel 217 formed by the first communication channel 213, the second communication channel 214, and the third communication channel 215, and the pressure generating chamber 211. The supply channel 217 communicates with the pressure generating chamber 211, supplying liquid to the pressure generating chamber 211.

[0117] The nozzle plate 220 is provided on one side of the flow channel substrate 210. The nozzle plate 220 is made of, for example, stainless steel (SUS). The nozzle plate 220 is bonded to the flow channel substrate 210 using, for example, an adhesive or a heat-sealed film. The nozzle plate 220 has a plurality of nozzle holes 222 formed along the X-axis. The nozzle holes 222 communicate with the pressure generating chamber 211 to discharge liquid.

[0118] The vibration plate 230 is provided on the other surface of the flow path forming substrate 210. The vibration plate 230 is composed of, for example, a silicon oxide layer 232 provided on the flow path forming substrate 210 and a zirconium oxide layer 234 provided on the silicon oxide layer 232.

[0119] The piezoelectric element 100 is provided on the vibration plate 230, for example. A plurality of piezoelectric elements 100 are provided. Figure 11Components of the piezoelectric element 100 other than the first electrode 10 , the piezoelectric layer 20 , and the wiring 70 are omitted from illustration.

[0120] In the liquid ejection head 200, the vibration plate 230 and the first electrode 10 are displaced due to the deformation of the piezoelectric layer 20 having electromechanical conversion characteristics. That is, in the liquid ejection head 200, the vibration plate 230 and the first electrode 10 essentially function as a vibration plate. Alternatively, the vibration plate 230 may be omitted, with only the first electrode 10 functioning as the vibration plate. When the first electrode 10 is directly provided on the flow path forming substrate 210, it is preferably protected by an insulating protective film or the like so that the liquid does not come into contact with the first electrode 10.

[0121] The protective substrate 240 is bonded to the vibration plate 230 via an adhesive (not shown). A through-hole 242 is formed in the protective substrate 240. In the illustrated example, the through-hole 242 extends through the protective substrate 240 in the Z-axis direction. The through-hole 242 communicates with the third communication passage 215. The through-hole 242 and the third communication passage 215 form a manifold 216 that serves as a common liquid chamber for each pressure generating chamber 211. Furthermore, a through-hole 244 is formed in the protective substrate 240, extending through the protective substrate 240 in the Z-axis direction. The end of the wiring 70 is located in the through-hole 244.

[0122] An opening 246 is formed in the protective substrate 240. The opening 246 is a space for not hindering the driving of the piezoelectric element 100. The opening 246 may be sealed or not sealed.

[0123] The circuit board 250 is provided on the protective substrate 240. The circuit board 250 includes a semiconductor integrated circuit (IC) for driving the piezoelectric element 100. The circuit board 250 and the wiring 70 are electrically connected via a connection wiring (not shown).

[0124] The flexible substrate 260 is provided on the protective substrate 240. The flexible substrate 260 includes a sealing layer 262 provided on the protective substrate 240 and a fixing plate 264 provided on the sealing layer 262. The sealing layer 262 is a layer for sealing the manifold 216. The sealing layer 262 is, for example, flexible. A through-hole 266 is formed in the fixing plate 264. The through-hole 266 penetrates the fixing plate 264 in the Z-axis direction. When viewed in the Z-axis direction, the through-hole 266 is provided at a position overlapping the manifold 216.

[0125] 3. Printer

[0126] Next, a printer according to this embodiment will be described with reference to the drawings. Figure 12 It is a perspective view schematically showing the printer 300 according to this embodiment.

[0127] The printer 300 is an inkjet printer. Figure 12 As shown, printer 300 includes a printhead assembly 310. Printhead assembly 310 includes, for example, liquid ejecting heads 200. The number of liquid ejecting heads 200 is not particularly limited. Printhead assembly 310 is detachably provided with cartridges 312 and 314 that constitute a supply unit. A carriage 316, carrying printhead assembly 310, is axially movable on a carriage shaft 322 mounted on a main body 320 of the device, and ejects liquid supplied from the liquid supply unit.

[0128] Here, the term "liquid" refers to any material in a liquid phase, including liquid materials such as sols and gels. Furthermore, liquids include not only liquids as a state of matter, but also materials formed by dissolving, dispersing, or mixing particles of functional materials composed of solid substances such as pigments or metal particles in a solvent. Representative examples of liquids include inks and liquid crystal emulsions. Inks include various liquid compositions, including general aqueous and oil-based inks, as well as gel inks and hot-melt inks.

[0129] In the printer 300, the driving force of the drive motor 330 is transmitted to the carriage 316 via a plurality of gears and a timing belt 332 (not shown), thereby moving the carriage 316 carrying the print head assembly 310 along the carriage shaft 322. Meanwhile, the device body 320 is provided with a transport roller 340 as a transport mechanism. This transport roller 340 moves a sheet S, such as a recording medium, relative to the liquid ejection head 200. The transport mechanism for transporting the sheet S is not limited to a transport roller, but may also be a belt, a drum, or the like.

[0130] The printer 300 includes a printer controller 350, which serves as a control unit for controlling the liquid ejecting head 200 and the transport roller 340. The printer controller 350 is electrically connected to the circuit board 250 of the liquid ejecting head 200. The printer controller 350 includes, for example, a RAM (Random Access Memory) for temporarily storing various data, a ROM (Read Only Memory) storing control programs, etc., a CPU (Central Processing Unit), and a drive signal generation circuit for generating drive signals for supplying the liquid ejecting head 200.

[0131] In addition, the piezoelectric element 100 is not limited to liquid ejection heads and printers, and can be used for a wide range of applications. The piezoelectric element 100 is suitable for use as piezoelectric actuators such as ultrasonic motors, vibrating dust removal devices, piezoelectric transformers, piezoelectric speakers, piezoelectric pumps, and pressure-to-electricity conversion devices. In addition, the piezoelectric element 100 is suitable for use as piezoelectric sensor elements such as ultrasonic detectors, angular velocity sensors, acceleration sensors, vibration sensors, tilt sensors, pressure sensors, collision sensors, human body sensors, infrared sensors, terahertz sensors, thermal detection sensors, pyroelectric sensors, and piezoelectric sensors. In addition, the piezoelectric element 100 is suitable for use as ferroelectric elements such as ferroelectric memories (FeRAMs), ferroelectric transistors (FeFETs), ferroelectric operational circuits (FeLogics), and ferroelectric capacitors. In addition, the piezoelectric element 100 is suitable for use as voltage-controlled optical elements such as wavelength converters, optical waveguides, optical path modulators, refractive index control elements, and electronic shutter mechanisms.

[0132] 4. Experimental Examples

[0133] 4.1. First experiment

[0134] 4.1.1. Preparation of samples

[0135] 4.1.1.1 Experimental Example 1

[0136] The surface of the single crystal silicon substrate was thermally oxidized to form a 1460 nm thick SiO2 layer. Next, a 400 nm thick Zr film was formed by DC (Direct Current) sputtering, and then heat treated at 850°C to form a ZrO2 layer.

[0137] Next, a Ti layer, a Pt layer, and an Ir layer were formed on the ZrO 2 layer by DC sputtering to have thicknesses of 20 nm, 80 nm, and 5 nm, respectively, as a first electrode.

[0138] Next, monomer solutions composed of potassium 2-ethylhexanoate, sodium 2-ethylhexanoate, and niobium 2-ethylhexanoate were synthesized. A mixed solvent of 2-ethylhexanoic acid and decane was used as the organic solvent. These monomer solutions were mixed to obtain a KNN precursor solution.

[0139] Next, the prepared KNN precursor solution was applied to the Ir layer via spin coating at 3000 rpm. The solution was then dried at 180°C for 2 minutes, degreased at 380°C for 2 minutes, and then lamp-annealed at 750°C for 3 minutes. This process formed a crystalline layer. The process from applying the KNN precursor solution to calcining the KNN precursor layer was repeated, forming a piezoelectric layer consisting of a 2μm-thick KNN layer.

[0140] Next, a moisture-resistant layer consisting of a 45 nm thick HfO2 layer was formed on the KNN layer. The HfO2 layer was formed by ALD using tetrakisdimethylaminohafnium (TDMAH) as the raw material, a film formation temperature of 85°C, and H2O as the oxidant.

[0141] Through the above, a sample of Experimental Example 1 was produced.

[0142] 4.1.1.2. Experimental Example 2

[0143] A sample of Experimental Example 2 was prepared in the same manner as in Experimental Example 1, except that the film-forming temperature of the HfO 2 layer was set to 150°C.

[0144] 4.1.1.3 Experimental Example 3

[0145] A sample of Experimental Example 3 was prepared in the same manner as in Experimental Example 1, except that the HfO 2 layer was not formed.

[0146] Experimental conditions

[0147] 4.1.2.1.SIMS

[0148] SIMS was performed on the samples of Experimental Examples 1 to 3. As SISM, an "IMS-7f sector SIMS" manufactured by CAMECA was used, and 15 keV Cs was injected into the primary ion beam at a beam current of 10 nA. + Raster scanning was performed at a 100μm angle, and negative secondary ions were detected from a central area of ​​33μmφ. An electron gun was used to prevent charging. The surface of the HfO2 layer was irradiated with an ion beam, and the amount of hydrogen incorporated into the HfO2 layer and the KNN layer was measured. The relative sensitivity factor (RSF) was calculated from the intensity detected by SIMS as described in "1.2. SIMS," and the hydrogen concentration was determined based on the relative sensitivity factor.

[0149] 4.1.2.2 Leakage current measurement

[0150] In the samples corresponding to Experimental Examples 1 to 3, a 50 nm thick Pt layer was deposited on the KNN layer of the sample using DC sputtering before forming the HfO2 layer. The HfO2 layer was then deposited. A voltage was then applied between the first electrode and the Pt layer on the KNN layer using a semiconductor parameter analyzer, and the leakage current was measured.

[0151] 4.1.3 Experimental results

[0152] Figure 13 This is a table showing the results of SIMS and leakage current measurement in Experimental Examples 1 to 3. Figure 14 It is a graph showing the results of SIMS of Experimental Examples 1 to 3. Figure 15It is a graph showing the results of leakage current measurement in Experimental Examples 1 to 3. Figure 13 The integrated hydrogen concentration is based on Figure 14 The distribution is calculated based on the integrated intensity within a range of 50 nm to 300 nm from the surface of the KNN layer. Figure 15 Drawn Figure 13 Leakage current shown. Figure 13 "E" shows the applied electric field in MV / m.

[0153] like Figures 13 to 15 As shown, the integrated hydrogen concentration is 9.75×10 14 atom / cm 2 The leakage current ratio of experimental example 1 is 1.89×10 15 atom / cm 2 The leakage current of Experimental Example 2 is small. The leakage current of Experimental Example 3, in which the integrated hydrogen concentration is lower than that of Experimental Example 1, is smaller than that of Experimental Example 1. It is known that when the integrated hydrogen concentration is low, the leakage current can be reduced.

[0154] 4.2. Second experiment

[0155] 4.2.1. Preparation of samples

[0156] 4.2.1.1. Experimental Example 4

[0157] As in Experimental Example 1 above, after forming the KNN layer, a 50nm-thick Pt layer was formed on the KNN layer of the sample using DC sputtering. Next, a moisture-resistant layer consisting of a 10nm-thick HfO2 layer was formed on the KNN layer. The HfO2 layer was formed using ALD, using TDMAH as the raw material, a film formation temperature of 150°C, and H2O as the oxidant. In Experimental Example 4, there was a region where the Pt layer was formed above the KNN layer, and a region where the Pt layer was not formed above the KNN layer.

[0158] Through the above, a sample of Experimental Example 4 was produced.

[0159] 4.2.1.2 Experimental Example 5

[0160] A sample of Experimental Example 5 was prepared by the same method as Experimental Example 4, except that the thickness of the HfO 2 layer was set to 45 nm, the film formation temperature was set to 250° C., and the oxidant was set to O 3 .

[0161] Experimental methods

[0162] SIMS was performed on the samples of Experiments 4 and 5 using the same method as described in Experiment 1. Although hydrogen concentration was not determined in this experiment, the intensity measured in this experiment correlated with hydrogen concentration. In each of Experiments 4 and 5, SIMS was performed on both the region where the Pt layer was formed above the KNN layer and the region where the Pt layer was not formed above the KNN layer.

[0163] 4.2.3 Experimental results

[0164] Figure 16 This is a table showing the SIMS results of Experimental Examples 4 and 5. Figure 17 is a graph showing the results of SIMS of Experimental Examples 4 and 5. Figure 16 and Figure 17 , the values ​​of Experimental Example 3 are also shown. Figure 16 The "SIMS average intensity" is based on Figure 17 The average value of the coordinate graph of the sample is calculated from the range of 500nm to 1500nm from the surface of the sample. Figure 16 and Figure 17 In each of Experimental Examples 4 and 5, the result of the region where the Pt layer was formed on the KNN layer was designated as “with Pt”, and the result of the region where the Pt layer was not formed on the KNN layer was designated as “without Pt”.

[0165] like Figure 16 and Figure 17 As shown, within the KNN layer, the intensity of the "with Pt" sample is smaller than that of the "without Pt" sample in Experiment 4. This is because the Pt layer inhibits the diffusion of hydrogen from H2O, the oxidant, into the KNN layer in the "with Pt" sample.

[0166] On the other hand, within the KNN layer, the intensity of the "with Pt" layer was greater than that of the "without Pt" layer in Experimental Example 5. This is believed to be because hydrogen introduced into the Pt layer during the manufacturing process diffused from the Pt layer into the KNN layer depending on the film formation temperature when the HfO2 layer was formed.

[0167] Therefore, as described in the above “1.3. Manufacturing Method”, it can be seen that if the Pt layer is formed after the HfO2 layer is formed, the hydrogen introduced into the Pt layer can be prevented from diffusing from the Pt layer to the KNN layer due to the film formation temperature when the HfO2 layer is formed.

[0168] 4.3. The third experiment

[0169] 4.3.1. Preparation of samples

[0170] 4.3.1.1. Experimental Example 6

[0171] A 1460nm-thick SiO2 layer was formed by thermally oxidizing the surface of the single-crystal silicon substrate. Next, a 45nm-thick HfO2 layer was formed as a moisture-resistant layer on the SiO2 layer. The HfO2 layer was formed using the ALD method6 using TDMAH as the raw material, a film formation temperature of 85°C, and H2O as the oxidant.

[0172] Through the above, a sample of Experimental Example 6 was produced.

[0173] 4.3.1.2 Experimental Example 7

[0174] A sample of Experimental Example 7 was produced in the same manner as in Experimental Example 6 except that the film formation temperature of the ALD method was set to 150°C.

[0175] 4.3.1.3 Experimental Example 8

[0176] The sample of Experimental Example 8 was prepared in the same manner as in Experimental Example 6 except that the HfO 2 layer was not formed.

[0177] 4.3.2 Experimental methods

[0178] After the samples of Experimental Examples 6 to 8 were exposed to heavy water vapor at a temperature of 80° C. and a humidity of 100%, SIMS was performed on the samples of Experimental Examples 6 to 8 using the same method as described in the first experimental example.

[0179] 4.3.3 Experimental results

[0180] Figure 18 Graph showing the results of SIMS of Experimental Examples 6 to 8. Figure 18 As shown, the deuterium concentration in the SiO2 layer was lower in Experimental Examples 6 and 7, where the HfO2 layer was formed, than in Experimental Example 8, where the HfO2 layer was not formed. In Experimental Examples 6 and 7, the deuterium concentration was 1 / 10 of that at the surface of the moisture-resistant layer within a range of 22 nm or less from the surface of the HfO2 layer. Furthermore, in Experimental Examples 6 and 7, the deuterium concentration in the HfO2 layer was higher than that in the SiO2 layer. This indicates that deuterium was trapped in the HfO2 layer. No significant difference was observed in Experimental Examples 6 and 7.

[0181] 4.4. Fourth Experiment

[0182] 4.4.1. Preparation of samples

[0183] After forming up to the KNN layer in the same manner as in Experimental Example 1, an IrO 2 layer and a Pt layer were sequentially formed on the KNN layer by sputtering.

[0184] Then, an HfO2 layer was formed by ALD. In ALD, H2O is used as an oxidant, such as Figure 19As shown, the film formation temperature was set to 85° C. or 150° C., and the thickness of the HfO 2 layer was set to 45 nm or 10 nm. In Experimental Examples 9 to 11, no HfO 2 layer was formed.

[0185] Next, a permanent resist was formed as an organic insulating layer by spin coating, drying, exposure, development, and curing. TMMR manufactured by Tokyo Ohka Kogyo Co., Ltd. was used as the permanent resist. Curing was performed by heating at 190°C for 1 hour. Figure 19 As shown, the film was cured in the atmosphere or in a vacuum. Next, an Au layer was formed as wiring by sputtering. In Experimental Examples 9, 12, 15, and 16, no organic insulating layer or wiring was formed.

[0186] Through the above, samples of Experimental Examples 9 to 16 were produced.

[0187] 4.4.2 Experimental methods

[0188] SIMS was performed on the samples of Experimental Examples 9, 12, 15, and 16 using the same method as described in Experimental Example 1. The hydrogen concentration at a position where the thickness of the KNN layer was 1 / 2 was determined.

[0189] Furthermore, the leakage currents of Experimental Examples 9 to 16 were measured by the same method as that described in the first experimental example.

[0190] 4.4.3 Experimental results

[0191] Figure 19 This is a table showing the experimental results of Experimental Examples 9 to 16. Figure 20 It is a graph showing the experimental results of Experimental Examples 9 to 16. Figure 19 and Figure 10 In the figure, the leakage current is the value when an electric field of 5 MV / m is applied.

[0192] like Figure 19 and Figure 20 As shown, by comparing Experimental Examples 13 and 14, it can be seen that when a 45 nm thick HfO2 layer is formed at a film forming temperature of 85°C, the leakage current is smaller when the organic insulating layer is cured in vacuum than when it is cured in the air.

[0193] The above-mentioned embodiment and modification examples are merely examples, and the present invention is not limited to these contents. For example, each embodiment and each modification example can be appropriately combined.

[0194] The present invention includes substantially the same configuration as that described in the embodiment, such as a configuration having the same function, method, and result, or a configuration having the same purpose and effect. In addition, the present invention includes a configuration in which a non-essential portion of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that can have the same effect as that of the configuration described in the embodiment, or a configuration that can achieve the same purpose. In addition, the present invention includes a configuration in which a known technology is added to the configuration described in the embodiment.

[0195] The following contents can be derived from the above-mentioned embodiment and modification examples.

[0196] One solution for piezoelectric elements is,

[0197] The method comprises: a first electrode, arranged above the substrate;

[0198] a piezoelectric layer disposed above the first electrode;

[0199] a second electrode disposed above the piezoelectric layer; and

[0200] a moisture-resistant layer covering at least a portion of the piezoelectric layer;

[0201] When the piezoelectric layer was subjected to secondary ion mass spectrometry, the hydrogen concentration calculated from the integrated intensity within a range of 50 nm to 300 nm from the surface of the piezoelectric layer was 1.50×10 15 atom / cm 2 the following.

[0202] According to this piezoelectric element, it is possible to improve moisture resistance while ensuring the insulation properties of the piezoelectric layer.

[0203] In one embodiment of the piezoelectric element,

[0204] The hydrogen concentration is 1.00×10 15 atom / cm 2 the following.

[0205] According to this piezoelectric element, the insulating properties of the piezoelectric layer can be further improved.

[0206] In one embodiment of the piezoelectric element,

[0207] The hydrogen concentration is 9.75×10 14 atom / cm 2 the following.

[0208] According to this piezoelectric element, the insulating properties of the piezoelectric layer can be further improved.

[0209] In one embodiment of the piezoelectric element,

[0210] comprising a third electrode disposed above the second electrode and electrically connected to the second electrode,

[0211] The material of the second electrode is metal oxide,

[0212] The third electrode is made of noble metal.

[0213] According to this piezoelectric element, the resistance of the electrode consisting of the second electrode and the third electrode can be reduced.

[0214] In one embodiment of the piezoelectric element,

[0215] The piezoelectric layer includes a portion where the second electrode, the moisture-resistant layer, and the third electrode are stacked in this order from the piezoelectric layer side.

[0216] According to this piezoelectric element, the second electrode can reduce etching damage or contamination of the piezoelectric layer when forming the contact hole in the moisture-resistant layer.

[0217] In one embodiment of the piezoelectric element,

[0218] The moisture-resistant layer is a layer formed by an atomic layer deposition method using ozone as an oxidizing agent.

[0219] According to this piezoelectric element, when the moisture-resistant layer is formed, it is possible to suppress the hydrogen introduced into the third electrode from diffusing into the piezoelectric layer.

[0220] In one embodiment of the piezoelectric element,

[0221] The moisture-resistant layer is a layer formed by an atomic layer deposition method using water as an oxidizing agent.

[0222] According to this piezoelectric element, a dense moisture-resistant layer can be formed.

[0223] In one embodiment of the piezoelectric element,

[0224] When the moisture-resistant layer was exposed to an atmosphere of 80° C. and 100% humidity for 24 hours and subjected to secondary ion mass spectrometry, the hydrogen concentration was 1 / 10 of that on the surface of the moisture-resistant layer within a range of 22 nm or less from the surface of the moisture-resistant layer.

[0225] According to this piezoelectric element, moisture resistance can be improved.

[0226] In one embodiment of the piezoelectric element,

[0227] The piezoelectric layer includes a composite oxide having a perovskite structure containing potassium, sodium, and niobium.

[0228] According to this piezoelectric element, since the piezoelectric layer does not contain lead, it is environmentally friendly.

[0229] One solution for the liquid ejection head is,

[0230] A method comprising: a piezoelectric element; and

[0231] a nozzle plate formed with nozzle holes,

[0232] The substrate includes a flow path forming substrate having a pressure generating chamber whose volume is changed by the piezoelectric element.

[0233] The nozzle hole is in communication with the pressure generating chamber.

[0234] One solution for the printer is,

[0235] Comprising: a solution of the liquid ejection head;

[0236] a transport mechanism for moving the recording medium relative to the liquid ejection head; and

[0237] The control unit controls the liquid ejection head and the conveying mechanism.

Claims

1. A piezoelectric element, characterized in that: Include: A first electrode is disposed above the substrate; a piezoelectric layer, disposed above the first electrode; a second electrode disposed above the piezoelectric layer; as well as a moisture-resistant layer covering at least a portion of the piezoelectric layer; When the piezoelectric layer was subjected to secondary ion mass spectrometry, the hydrogen concentration calculated from the integrated intensity within a range of 50 nm to 300 nm from the surface of the piezoelectric layer was 1.50×10 15 atom / cm 2 the following.

2. The piezoelectric element according to claim 1, wherein The hydrogen concentration is 1.00×10 15 atom / cm 2 the following.

3. The piezoelectric element according to claim 1, wherein The hydrogen concentration is 9.75×10 14 atom / cm 2 the following.

4. The piezoelectric element according to claim 1, wherein The piezoelectric element includes a third electrode disposed above the second electrode and electrically connected to the second electrode. The material of the second electrode is metal oxide, The third electrode is made of noble metal.

5. The piezoelectric element according to claim 4, wherein The piezoelectric element includes a portion in which the second electrode, the moisture-resistant layer, and the third electrode are stacked in this order from the piezoelectric layer side. The piezoelectric element according to claim 5 , wherein: The moisture-resistant layer is a layer formed by an atomic layer deposition method using ozone as an oxidizing agent.

7. The piezoelectric element according to claim 5, wherein The moisture-resistant layer is a layer formed by an atomic layer deposition method using water as an oxidizing agent.

8. The piezoelectric element according to claim 1, wherein When the moisture-resistant layer was exposed to an atmosphere of 80° C. and 100% humidity for 24 hours and subjected to secondary ion mass spectrometry, the hydrogen concentration was 1 / 10 of that on the surface of the moisture-resistant layer within a range of 22 nm or less from the surface of the moisture-resistant layer.

9. The piezoelectric element according to claim 1, wherein The piezoelectric layer includes a composite oxide having a perovskite structure containing potassium, sodium, and niobium.

10. A liquid ejection head, characterized in that: Include: The piezoelectric element according to any one of claims 1 to 9; and a nozzle plate formed with nozzle holes, The substrate includes a flow path forming substrate having a pressure generating chamber whose volume is changed by the piezoelectric element. The nozzle hole is in communication with the pressure generating chamber.

11. A printer, characterized in that: Include: The liquid ejection head according to claim 10; a transport mechanism for moving the recording medium relative to the liquid ejection head; and The control unit controls the liquid ejection head and the conveying mechanism.

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