# US 2024/0206342 A1 · Piezoelectric film, piezoelectric stack, piezoelectric element, and method for producing piezoelectric stack > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0206342 A1 - Document ID: US20240206342A1 - Status: Published application - Kind: A1 - Application number: 17/908,899 - Filed: 2021-02-24 - Published: 2024-06-20 - Earliest claimed: 2020-03-05 - Assignees: Sumitomo Chemical Company, Limited - Applicants: Sumitomo Chemical Company, Limited - Inventors: Toshiaki KURODA; Kenji SHIBATA; Kazutoshi WATANABE; Takeshi KIMURA - Web page: https://patentgrep.com/patent/US20240206342A1 ## CPC - H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles} - H10N 30/8542: {Alkali metal based oxides, e.g. lithium, sodium or potassium niobates} - C04B 35/495: based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates - C04B 35/6262: {of calcined, sintered clinker or ceramics} - C04B 35/62675: {characterised by the treatment temperature} - C23C 14/088: {of the type ABO3 with A representing alkali, alkaline earth metal or Pb and B representing a refractory or rare earth metal} - C30B 28/12: directly from the gas state - C30B 29/02: Elements - C30B 29/30: Niobates; Vanadates; Tantalates - C30B 29/68: Crystals with laminate structure, e.g. "superlattices" - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - H10N 30/076: by vapour phase deposition - H10N 30/708: {Intermediate layers, e.g. barrier, adhesion or growth control buffer layers} - C04B 2235/3201: Alkali metal oxides or oxide-forming salts thereof - C04B 2235/40: Metallic constituents or additives not added as binding phase - C04B 2235/407: Copper - C04B 2235/785: Submicron sized grains, i.e. from 0,1 to 1 micron - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR ## Abstract There is provided a piezoelectric film, being a polycrystalline film comprised of potassium sodium niobate; containing at least one metal element selected from a group consisting of Cu and Mn; and having 1.0 or less ratio of a concentration B of the metal element at grain boundaries of crystals, with respect to a concentration A of the metal element in a matrix phase of the crystals. ## Claims ### Claim 1 A piezoelectric film, being a polycrystalline film comprised of potassium sodium niobate; containing at least one metal element selected from a group consisting of Cu and Mn; and having 1.0 or less ratio of a concentration B of the metal element at grain boundaries of crystals, with respect to a concentration A of the metal element in a matrix phase of the crystals. ### Claim 2 (depends on 1) The piezoelectric film according to claim 1, wherein the ratio of the concentration B, with respect to the concentration A, is 0.8 or less. ### Claim 3 (depends on 1) The piezoelectric film according to claim 1, wherein a total concentration of the metal element present in the matrix phase of the crystals and the metal element present at the grain boundaries of the crystals is 0.2 at % or more and 2.0 at % or less relative to an amount of niobium in the polycrystalline film. ### Claim 4 (depends on 1) The piezoelectric film according to claim 1, wherein the piezoelectric film is constituted by crystal grains having an average grain size of 100 nm or more. ### Claim 5 A piezoelectric stack, comprising: a substrate; an electrode film provided on the substrate; and a piezoelectric film provided on the electrode film, the piezoelectric film being a polycrystalline film comprised of potassium sodium niobate, wherein the piezoelectric film contains at least one metal element selected from a group consisting of Cu and Mn, and a ratio of a concentration B of the metal element at grain boundaries of crystals constituting the piezoelectric film, with respect to a concentration A of the metal element in a matrix phase of the crystals, is 1.0 or less. ### Claim 6 A piezoelectric element, comprising: a substrate; a bottom electrode film provided on the substrate; a piezoelectric film provided at the bottom electrode film, the piezoelectric film being a polycrystalline film comprised of potassium sodium niobate; and a top electrode film provided on the piezoelectric film, wherein the piezoelectric film contains at least one metal element selected from a group consisting of Cu and Mn, and a ratio of a concentration B of the metal element at grain boundaries of crystals constituting the piezoelectric film, with respect to a concentration A of the metal element in a matrix phase of the crystals, is 1.0 or less. ### Claim 7 A method for producing a piezoelectric stack, comprising: depositing an electrode film on a substrate; and depositing a piezoelectric film on the electrode film, the piezoelectric film being a polycrystalline film comprised of potassium sodium niobate, wherein in the deposition of the piezoelectric film, the piezoelectric film is deposited by a sputtering method using a target material in which at least one metal element selected from a group consisting of Cu and Mn is dissolved in a matrix phase, the piezoelectric film having 1.0 or less ratio of a concentration B of the metal element at grain boundaries of crystals constituting the piezoelectric film, with respect to a concentration A of the metal element in a matrix phase of the crystals.