Potassium sodium niobate sinter and sputtering target formed from the sinter

Abstract

An object of the present disclosure is to provide a dense potassium sodium niobate sintered body and a sputtering target capable of producing a thin film having a desired composition and crystal phase. A potassium sodium niobate sintered body containing potassium (K), sodium (Na), niobium (Nb), and oxygen (O) satisfies 1 < (K+Na) / Nb ≤ 1.3 in terms of atomic ratio, and has a dimensional density of 3.9 g / cm 3 The above.

Description

Technical Field

[0001] This disclosure relates to a sintered body of potassium sodium niobate and a sputtering target formed from the sintered body. Background Technology

[0002] Lead-based PZT (lead zirconate titanate) is used as a piezoelectric material in sensors, actuators, and other applications due to its excellent piezoelectric properties. While PZT possesses good and stable piezoelectric properties, its lead content results in a high environmental impact, particularly in Europe where its use is restricted by RoHS (Restriction of Hazardous Substances) and ELV (End-of-Life Vehicles Directive). Therefore, finding a lead-free alternative to piezoelectric materials has become a research topic.

[0003] Various alternative materials have been studied, but finding one that matches the properties and stability of PZT is not easy, and PZT is currently still used as an exemption from RoHS. Against this backdrop, sodium potassium niobate (KNN) is considered to have piezoelectric properties relatively close to those of PZT and has therefore been listed as a candidate alternative to lead-free PZT. For example, Patent Document 1 discloses a piezoelectric material made of sodium potassium niobate.

[0004] Specifically, the compositional formula (K) is disclosed. a Na 1－a ) x A piezoelectric layer represented by NbO3 (0.1 < a < 1, 1 ≤ x ≤ 1.2) is described. Furthermore, it is described that potassium or sodium, or other components, can be added in excess as needed. Regarding the manufacturing method of this piezoelectric layer, it is described that a piezoelectric material is produced by coating a precursor solution having the above-described composition onto a substrate, followed by annealing to crystallize it (sol-gel method). It is also described that it can be produced by MOD method, laser ablation method, or sputtering method.

[0005] Patent Document 2 describes a sputtering target capable of manufacturing a piezoelectric film (KNN film) of alkali metal niobium oxide. Furthermore, Patent Document 3 discloses the use of a sputtering target composed of the formula (K... 1－x Na x A sputtering target formed from a sintered body of NbO3 (0 < x < 1) is used to form a thin film by RF magnetron sputtering. Specifically, a high-density sodium potassium niobate sputtering target is disclosed.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-033210

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-161074

[0010] Patent Document 3: International Publication No. 2019 / 167657 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] When forming thin films using a sodium potassium niobate sputtering target, the following problems arise: the alkali component volatilizes, making it impossible to obtain the desired composition, and it is also impossible to obtain a sintered body with the desired density. In view of these problems, the object of this disclosure is to provide a dense sodium potassium niobate sintered body capable of producing a thin film having the desired composition, and a sputtering target formed from the sintered body.

[0013] Solution for solving the problem

[0014] The main points of this disclosure are as follows.

[0015] [1] A sintered body of potassium sodium niobate, containing potassium (K), sodium (Na), niobium (Nb), and oxygen (O), having an atomic ratio satisfying 1.0 < (K + Na) / Nb ≤ 1.3, and a dimensional density of 3.9 g / cm³. 3 above.

[0016] [2] According to the potassium sodium niobate sintered body described in [1], wherein, the content belonging to (K) 1－x Na x The X-ray diffraction peak intensity of the (022) plane of the NbO3 (0 < x < 1) phase is used as I TG The average X-ray diffraction intensity within the range of 15.0° ≤ 2θ ≤ 16.0° will be used as I. BG At that time, I TG / I BG It is above 50.

[0017] [3] The potassium sodium niobate sintered body according to [1] or [2], wherein the volume resistivity is 1.0 × 10⁻⁶. 4 Ω·cm or more and 1.0×10 10 Below Ω·cm.

[0018] [4] A sputtering target, which is formed from any one of the potassium sodium niobate sintered bodies [1] to [3].

[0019] Invention Effects

[0020] According to this disclosure, it is possible to provide a dense potassium sodium niobate sintered body that can be used to fabricate a thin film having a desired composition and a sputtering target formed from the sintered body. Detailed Implementation

[0021] The following describes specific embodiments of this disclosure. However, each component and its combination in each embodiment is only an example. Without departing from the spirit of this disclosure, appropriate additions, omissions, substitutions and other changes can be made to the components.

[0022] [Sintered body of potassium sodium niobate]

[0023] The present disclosure discloses a potassium sodium niobate sintered body containing potassium (K), sodium (Na), niobium (Nb), and oxygen (O). The composition of this sintered body, in terms of atomic ratio, satisfies 1.0 < (K + Na) / Nb ≤ 1.3. In this formula, K, Na, and Nb represent the atomic ratio (at%) of each component contained in the sintered body. Conventional potassium sodium niobate sintered bodies contain alkali metals (potassium, sodium) and niobium in an atomic ratio of 1:1, while the potassium sodium niobate sintered body of this embodiment is characterized by containing more alkali metals (alkali-rich) relative to niobium.

[0024] When using a potassium sodium niobate sintered body containing alkali metals and niobium in a conventional 1:1 atomic ratio for film formation, the alkali metal content is reduced, resulting in (K + Na) / Nb < 0.9 in the film. 1―x Na x The NbO3 phase cannot be sufficiently crystallized, thus failing to achieve the desired piezoelectric properties. This embodiment utilizes a sintered potassium sodium niobate body satisfying 1 < (K + Na) / Nb ≤ 1.3 to form a film, enabling the formation of a thin film with a ratio of 0.9 ≤ (K + Na) / Nb ≤ 1.1. The atomic ratio of this sintered body is preferably (K + Na) / Nb ≤ 1.2, and more preferably (K + Na) / Nb ≤ 1.1.

[0025] Furthermore, the dimensional density of the potassium sodium niobate sintered body in this embodiment is 3.9 g / cm³. 3 The above is an explanation. When using this sintered body for film formation, a higher dimensional density of the sintered body better suppresses particle formation during film formation. For conventional potassium sodium niobate sintered bodies containing alkali metals and niobium in an atomic ratio of 1:1, increasing the density requires setting the sintering temperature above 900°C, which leads to severe wear and tear on sintering equipment components. However, the potassium sodium niobate sintered body of this disclosure exhibits improved sintering performance, achieving high density even at sintering temperatures below 900°C. A more preferred dimensional density is 4.1 g / cm³. 3 above.

[0026] The sintered body of potassium sodium niobate in this embodiment preferably satisfies the following condition: [The following text appears to be a separate, unrelated section:] ...attributed to K... 1―xNa x The X-ray diffraction peak intensity of the (022) plane of the NbO3 (0 < x < 1) phase is used as I TG The average X-ray diffraction intensity within the range of 15.0° ≤ 2θ ≤ 16.0° will be used as I. BG At that time, I TG / I BG It is above 50. K 1―x Na x The (022) plane of the NbO3 (0 < x < 1) phase typically shows a peak at a diffraction angle (2θ) of 45° ≤ 2θ ≤ 46°. If I TG / I BG If the concentration is above 50, it can be considered that it has been fully crystallized into K. 1―x Na x NbO3 phase. On the other hand, if crystallization is insufficient, the desired piezoelectric properties may not be obtained.

[0027] The preferred volume resistivity of the potassium sodium niobate sintered body in this embodiment is 1×10⁻⁶. 4 Ω·cm or more, 1×10 10 Below Ω·cm. The sputtering target formed from this sintered body, if its volume resistivity is 1×10⁻⁶... 4 With a volume resistivity of Ω·cm or higher, low-speed film deposition via RF (radio frequency) sputtering is possible, making film thickness control easier. A volume resistivity of 1.0 × 10⁻⁶ is more preferred. 5 Ω·cm or higher. On the other hand, if it exceeds 1×10 10 If the sputtering temperature is less than Ω·cm, it is difficult to control the film properties by adjusting the sputtering conditions; therefore, a temperature of 1×10⁻⁶ is preferred. 10 Below Ω·cm. More preferably, the volume resistivity is 1×10⁻⁶. 9 Below Ω·cm.

[0028] The potassium sodium niobate sintered body of this embodiment may contain one or more elements selected from the group consisting of: Li (Group 1), Mg, Ca, Sr, Ba (Group 2), Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu (Rare Earth elements), Cu, Mn, Ti, V, Cr, Fe, Co, Ni, Cu, Zr, Mo, Ag, Hf, Ta, W (Transition metals), Al, Zn, Ga, In (Amphoteric metals), and Si, Ge, Sn, Sb, Bi (Half-metals). The dopant can adjust the crystallinity, piezoelectric properties, and electrical properties of the piezoelectric film.

[0029] The sintered body of this embodiment can be used as a material for PVD (physical vapor deposition), for example, as a sputtering target, a vacuum evaporation material, or an ion plating material. When used as a sputtering target, it can be formed into a disc-shaped plate, a rectangular plate, or a cylindrical shape. Furthermore, it can be bonded to a bonding material via a backing plate. Additionally, when used as a sputtering target, its thickness can be 20 mm or less, preferably 3.0 to 15 mm, and more preferably 6.0 to 12 mm. Furthermore, the area of ​​the sputtered surface is preferably 182 cm². 2 above.

[0030] [Method for manufacturing potassium sodium niobate sintered body]

[0031] The manufacturing method of the potassium sodium niobate sintered body, particularly the sputtering target, according to embodiments of this disclosure will be described. However, it is obvious that the manufacturing conditions, etc., described below are not limited to the scope disclosed, and some omissions or modifications may be made. Furthermore, in order to avoid unnecessarily obscuring the disclosed manufacturing method, detailed descriptions of known manufacturing processes and handling operations will be omitted.

[0032] (Raw material powder)

[0033] Prepare Nb₂O₅ powder, K₂CO₃ powder, Na₂CO₃ powder, or KNbO₃ powder and NaNbO₃ powder as raw material powders. When the particle size of the raw material powder is large, for example, in the case of a particle size D... 50 When the median particle size is greater than 1 mm, subsequent mixing and pulverization become difficult. Therefore, it is desirable to pulverize each raw material powder before weighing.

[0034] (Mixing and grinding process)

[0035] Weigh Nb₂O₅ powder, K₂CO₃ powder, Na₂CO₃ powder, etc., to achieve the desired composition ratio (alkali-rich). After weighing, mix them. To obtain a dense and uniform sintered body, attention should be paid to using mixers such as ball mills or vertical sand mills (Attritor mills) for thorough micronization and uniform mixing.

[0036] (Synthesis process)

[0037] After mixing, the mixed powder is filled into an alumina or mullite crucible and heat-treated in an atmospheric atmosphere at temperatures above 700°C and below 900°C to obtain K containing the desired composition. 1―x Na x NbO3 (0 < x < 1) synthetic powder. If the heat treatment temperature is below 700℃, K may not be obtained. 1―x Na x NbO3 (0 < x < 1). On the other hand, if the heat treatment temperature is higher than 900℃, the alkali component is more likely to volatilize.

[0038] (Grinding process)

[0039] After synthesis, the synthesized powder is subjected to dry or wet pulverization. For wet pulverization, the amount of media is determined based on the amount of raw materials after weighing. The particle size of the media can be set to 0.5 mm or 1.0 mm, and the media material can be alumina (Al₂O₃) or zirconium oxide (ZrO₂). The dispersion medium can be water or ethanol; if water is used, it is preferable to recover all of it when removing the mixed slurry. The pulverization method can be wet ball milling or wet bead milling, and the pulverization time can be more than 1 hour. It is preferred to use the above pulverization method for mixing and pulverizing until the particle size D is reached. 50 The median particle size reaches below 2 μm. After wet mixing, the mixed powder is dried, then deagglomerated and sieved. Because the alkali component is easily volatile and the temperature of the subsequent sintering process has an upper limit, the density of the sintered body cannot be increased if the powder is not sufficiently pulverized.

[0040] (Sintering process)

[0041] Preferably, the mixed powder is filled into a graphite mold and sintered by hot pressing (H / P) in an inert gas or vacuum atmosphere. When the raw material mixing ratio is 1.0 < (K + Na) / Nb < 1.1, the sintering temperature is preferably 710°C or higher and 880°C or lower. Conversely, when the alkali metal composition ratio is 1.1 ≤ (K + Na) / Nb ≤ 1.3, the sintering temperature is preferably 710°C or higher and 800°C or lower. If the sintering temperature is too high, the volatilization of the alkali component will increase, and the wear of the graphite mold will be aggravated. On the other hand, if the sintering temperature is too low, a dense sintered body cannot be obtained. Furthermore, the surface pressure is preferably set to 200–400 kgf / cm². 2 If the surface pressure is below 100 kgf / cm² 2 If the density of the sintered body cannot be sufficiently increased; if it exceeds 400 kgf / cm³, the density will be insufficient. 2 If this is not the case, the possibility of cracking during sintering increases.

[0042] (Regarding finishing)

[0043] The sintered body obtained through the above sintering process can be processed into the desired PVD material using surface grinders, cylindrical grinders, machining equipment, and other processing machinery, as needed. For sputtering targets, they can be processed into flat discs, rectangles, cylinders, etc.

[0044] [Example]

[0045] The following description is based on embodiments and comparative examples. It should be noted that this embodiment is merely an example and is not intended to limit the invention in any way. That is, the invention is defined only by the claims and includes various modifications beyond those described in this disclosure.

[0046] The evaluation methods used in the examples and comparative examples are as follows.

[0047] (Regarding composition analysis)

[0048] The following apparatus was used to analyze the composition of the sintered body.

[0049] Apparatus: SPS3500DD, manufactured by SII Corporation. Method: ICP-OES (Inductively Coupled Plasma Emission Spectrometry).

[0050] (Regarding size density)

[0051] A specified dimension (approximately 20×20×10mm) was cut from the sintered body. The length, width, and thickness were measured using vernier calipers, and the volume was calculated. Furthermore, the weight of the sintered body was determined using an electronic balance, and the dimensional density (bulk density) (g / cm³) was calculated. 3 = Weight / Volume. The lower limit of measurement for a vernier caliper is 0.01 mm. The lower limit of measurement for an electronic balance is 0.01 g.

[0052] (Regarding volume resistivity)

[0053] The sintered body (central part) sample was machined into a square shape. On the surface 2mm below the ground, the volume resistivity was measured three times using the following apparatus, and the average value was calculated. Apparatus: Nitto Seiko Analytical Technology Co., Ltd. UX MCP-HT800 High Resistance Resistivity Meter. Method: Constant voltage application / leakage current measurement. Technique: Dual-ring electrode method. Measurement temperature: Room temperature (20~25℃). Applied voltage: 10V.

[0054] (Analysis of crystal phase)

[0055] Crystal phase analysis was performed using the following apparatus. Principle: X-ray diffraction. Apparatus: Rigaku Smart Lab. X-ray tube: Cu-Kα rays. Tube voltage: 40 kV. Current: 30 mA. Measurement method: 2θ-θ reflection method. Scanning speed: 20° / min. Sampling interval: 0.02°. Measurement range (2θ): 10°–60°. Divergence slit: 1°. Divergence vertical confinement slit: 10 mm. Scattering slit: 8 mm. Receiving slit: Open. Goniometer: Sample horizontal type. Sample measurement position: Sputtering surface side.

[0056] (Example 1)

[0057] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed according to a mixing ratio of (K + Na):Nb = 1.20:1 (atomic ratio), and then mixed using a rotary dry mixer. It should be noted that the blade rotation speed was set to 3000 rpm, and the mixing time was 3 minutes. Then, the mixed powder was heat-treated at 800℃ to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and then subjected to wet bead milling. After wet bead milling, the powder was dried, depolymerized, and sieved using a 250 μm sieve. Using this powder, sintering was performed under an argon atmosphere at a temperature of 750 °C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under specific conditions. The resulting sintered body had a composition ratio of (K + Na) / Nb = 1.21, which met the desired ratio. Furthermore, a dimensional density of 4.26 g / cm³ was obtained. 3 The volume resistivity is 1.40 × 10⁻⁶. 5 The desired product is measured in Ω·cm. The results are shown in Table 1.

[0058] [Table 1]

[0059]

[0060] (Example 2)

[0061] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.10:1 (atomic ratio). The resulting mixture was then heat-treated at 800°C to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and subjected to wet bead milling. Similar to Example 1, the wet bead milled powder was dried, depolymerized, and sieved. Using this powder, under an argon atmosphere, it was sintered at a temperature of 750°C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under the specified conditions. As shown in Table 1, the obtained sintered body had a composition ratio of (K + Na) / Nb = 1.13, which meets the desired composition ratio. Furthermore, a dimensional density of 4.32 g / cm³ was obtained. 3 The volume resistivity is 1.70 × 10⁻⁶ 5 The desired product is Ω·cm.

[0062] (Example 3)

[0063] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.16:1 (atomic ratio). The resulting mixture was then heat-treated at 800°C to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and subjected to wet bead milling. Similar to Example 1, the wet bead milled powder was dried, depolymerized, and sieved. Using this powder, under an argon atmosphere, sintering was performed at a temperature of 720°C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under the specified conditions. As shown in Table 1, the obtained sintered body had a composition ratio of (K + Na) / Nb = 1.16, which meets the desired composition ratio. Furthermore, a dimensional density of 4.16 g / cm³ was obtained. 3 The volume resistivity is 1.76 × 10⁻⁶ 6 The desired product is Ω·cm.

[0064] (Example 4)

[0065] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.05:1 (atomic ratio). The mixed powder was then heat-treated at 800°C to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and subjected to wet bead milling. Similar to Example 1, the wet bead milled powder was dried, depolymerized, and sieved. Using this powder, under an argon atmosphere, it was sintered at a temperature of 875°C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under the specified conditions. As shown in Table 1, the obtained sintered body had a composition ratio of (K + Na) / Nb = 1.05, which meets the desired composition ratio. Furthermore, a dimensional density of 3.90 g / cm³ was obtained. 3 The volume resistivity is 6.21 × 10⁻⁶. 6 The desired product is Ω·cm.

[0066] (Comparative Example 1)

[0067] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.20:1 (atomic ratio). The mixed powder was then heat-treated at 800°C to produce K... 1－x Na xNbO3 (0 < x < 1) synthetic powder was obtained and then subjected to wet bead milling. Following this, as in Example 1, the wet bead milled powder was dried, depolymerized, and sieved. Using this powder, under an argon atmosphere, sintering was performed at a temperature of 700°C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under the specified conditions. As shown in Table 1, the obtained sintered body had a composition ratio of (K + Na) / Nb = 1.21, which met the desired composition ratio, but had a low dimensional density of 3.85 g / cm³. 3 This can be attributed to the low sintering temperature.

[0068] (Comparative Example 2)

[0069] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.20:1 (atomic ratio). The mixed powder was then heat-treated at 800°C to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and then subjected to wet bead milling. Following this, as in Example 1, the wet bead milled powder was dried, depolymerized, and sieved. Using this powder, under an argon atmosphere, sintering was performed at a temperature of 835°C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under the specified conditions. As shown in Table 1, the obtained sintered body had a composition ratio of (K + Na) / Nb = 1.00, which did not meet the desired ratio. This can be attributed to the excessively high sintering temperature relative to the alkali metal composition, leading to the volatilization of the alkali components.

[0070] (Comparative Example 3)

[0071] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.20:1 (atomic ratio). The mixed powder was then heat-treated at 800°C to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and then subjected to wet bead milling. Following this, as in Example 1, the wet bead milled powder was dried, depolymerized, and sieved. Using this powder, under an argon atmosphere, sintering was performed at a temperature of 750°C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under the specified conditions. As shown in Table 1, the obtained sintered body had a composition ratio of (K + Na) / Nb = 1.21, which met the desired composition ratio, but had a low dimensional density of 3.89 g / cm³.3 It can be assumed that although this is also related to the sintering temperature, it is mainly due to the large particle size of the powder after synthesis.

[0072] (Comparative Example 4)

[0073] KNbO3 powder and NaNbO3 powder were weighed to a mixing ratio of (K + Na):Nb = 1.00:1 (atomic ratio), and then mixed using a rotary dry mixer in the same manner as in Example 1. The mixed powder was then heat-treated at 800°C to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and then subjected to wet bead milling. Following this, as in Example 1, the wet bead milled powder was dried, depolymerized, and sieved. Using this powder, under an argon atmosphere, it was sintered at a temperature of 950°C and a surface pressure of 250 kgf / cm². 2 Hot pressing sintering was performed under specific conditions. As shown in Table 1, the composition ratio of the obtained sintered body was (K + Na) / Nb = 1.00. Due to the high sintering temperature, the graphite mold was severely consumed.

[0074] (Comparative Example 5)

[0075] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.00:1 (atomic ratio). The mixed powder was then heat-treated at 800°C to produce K... 1－x Na x NbO3 (0 < x < 1) synthetic powder was obtained and subjected to wet bead milling. Then, similar to Example 1, the wet bead milled powder was dried, depolymerized, and sieved. The powder was then filled into a mold, pressed to form a sintered body, and then sintered at atmospheric pressure at a sintering temperature of 950°C. As shown in Table 1, the volume resistivity of the obtained sintered body reached 3.15 × 10⁻⁶. 10 Ω·cm.

[0076] (Comparative Example 6)

[0077] KNbO3 powder, NaNbO3 powder, K2CO3 powder, and Na2CO3 powder were weighed and mixed using a rotary dry mixer with a mixing ratio of (K + Na):Nb = 1.00:1 (atomic ratio). The mixed powder was then heat-treated at 800°C to produce K... 1－x Na xNbO3 (0 < x < 1) synthetic powder was obtained and then subjected to wet bead milling. Following the same procedure as in Example 1, the wet bead milled powder was dried, depolymerized, and sieved. The powder was then filled into a mold, pressed to form a sintered body, and then sintered at atmospheric pressure in an oxygen atmosphere at a sintering temperature of 950°C. As shown in Table 1, the volume resistivity of the obtained sintered body reached 2.75 × 10⁻⁶. 11 Ω·cm.

[0078] Industrial availability

[0079] According to this disclosure, it is possible to provide a dense sodium potassium niobate sintered body capable of producing a thin film having a desired composition and crystalline phase, and a sputtering target formed from the sintered body. Using the sodium potassium niobate sputtering target of this embodiment, piezoelectric elements for sensors, actuators, etc., can be formed.

Claims

1. A sintered body of potassium sodium niobate, wherein, It contains potassium (K), sodium (Na), niobium (Nb), and oxygen (O). The composition of the sintered potassium sodium niobate body satisfies the following atomic ratio: 1.0 < (K + Na) / Nb ≤ 1.3, and the dimensional density is 3.9 g / cm³. 3 above.

2. The potassium sodium niobate sintered body according to claim 1, wherein, To be attributed to (K) 1－x Na x The X-ray diffraction peak intensity of the (022) plane of the NbO3 phase is used as I TG Where 0 < x < 1, the average value of the X-ray diffraction intensity in the range of 15.0° ≤ 2θ ≤ 16.0° will be taken as I. BG At this time, I TG / I BG It is above 50.

3. The potassium sodium niobate sintered body according to claim 1 or 2, wherein, The volume resistivity of the potassium sodium niobate sintered body is 1.0 × 10⁻⁶. 4 Ω·cm or more and 1.0×10 10 Below Ω·cm.

4. A sputtering target formed from a sintered body of potassium sodium niobate as described in claim 1 or 2.

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