# US 2023/0053780 A1 · Method for forming diamond product > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0053780 A1 - Document ID: US20230053780A1 - Status: Published application - Kind: A1 - Application number: 17/759,173 - Filed: 2021-03-04 - Published: 2023-02-23 - Earliest claimed: 2020-03-06 - Assignees: Element Six Technologies Limited; University of Warwick - Applicants: Element Six Technologies Limited; University of Warwick - Inventors: Joshua James Tully; Samuel James Cobb; Julie Victoria MacPherson; Mark Edward Newton; Matthew Lee Markham - Web page: https://patentgrep.com/patent/US20230053780A1 ## CPC - C25F 3/12: of semiconducting materials - C01B 32/25: Diamond - C01B 32/28: After-treatment, e.g. purification, irradiation, separation or recovery - C23C 14/0605: {Carbon} - C23C 14/48: Ion implantation - C25F 3/14: locally - C30B 29/04: Diamond - C30B 33/06: Joining of crystals - C30B 33/10: in solutions or melts - H10P 50/00: Etching of wafers, substrates or parts of devices - H10P 50/613: {of Group IV materials} - H10P 90/12: {Preparing bulk and homogeneous wafers} - C01P 2002/90: Other crystal-structural characteristics not specified above - C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - 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 - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS ## Abstract A method for forming a diamond product. Diamond material is provided and a damage layer comprising sp2 bonded carbon is formed in the material. The presence of the damage layer defines a first diamond layer above and in contact with the damage layer and a second diamond layer below and in contact with the damage layer. The damage layer is electrochemically etched to separate it from the first layer, wherein the electrochemical etching is performed in a solution containing ions, the solution having an electrical conductivity of at least 500 μS cm−1, and wherein the ions are capable of forming radicals during electrolysis. The diamond product is also described. ## Claims ### Claim 1 A method for forming a diamond product comprising: providing a diamond material; forming a damage layer comprising sp2 bonded carbon, wherein the presence of the damage layer defines a first diamond layer above and in contact with the damage layer and a second diamond layer below and in contact with the damage layer; and electrochemically etching the damage layer to separate therefrom the first layer, wherein the electrochemical etching is performed in a solution containing ions, the solution having an electrical conductivity of at least 500 μS cm−1, and wherein the ions are capable of forming radicals during electrolysis. ### Claim 2 (depends on 1) The method according claim 1, wherein the ions are selected from any of persulfate ions, sulfate ions, oxalate ions, chloride ions, carbonate ions and metal ions. ### Claim 3 (depends on 1) The method according to claim 1, wherein the etching occurs at an etch rate selected from any of at least 2 mm2 hr−1, at least 5 mm2 hr−1, at least 10 mm2 hr−1, 20 mm2hr−1, 30 mm2hr−1, and at least 40 mm2hr−1. ### Claim 4 (depends on 1) The method according to claim 1, wherein etch rate is measured by aligning the diamond material comprising the damage layer with electrodes in an electrochemical cell to allow imaging of the diamond material and monitoring the material loss of the diamond material over time. ### Claim 5 (depends on 1) The method according to claim 1, wherein the electrochemical etching is performed in an electrochemical cell comprising at least an anode, a cathode and an electrolyte, and the ions are present in the electrolyte. ### Claim 6 (depends on 1) The method according to claim 1, wherein the ions are present during the electrochemical etching at a concentration of between 0.01 M and an upper limit of the solubility of the ions in the electrolyte. ### Claim 7 (depends on 1) The method according to claim 1, wherein the electrochemical etching is performed at a temperature selected from any of at least 50° C., at least 70° C. and at least 90° C. ### Claim 8 (depends on 1) The method according to claim 1, wherein the first and second diamond layers comprise diamond formed by chemical vapour deposition (CVD). ### Claim 9 (depends on 1) The method according to claim 1, wherein the diamond material is single crystal diamond material. ### Claim 10 (depends on 9) The method according to claim 9, wherein the single crystal diamond material has a largest linear dimension selected from any of at least 6 mm, at least 8 mm, at least 10 mm, at least 15 mm and at least 20 mm. ### Claim 11 (depends on 1) The method according to claim 1, wherein the diamond material is polycrystalline diamond material. ### Claim 12 (depends on 1) The method according to claim 1, wherein the diamond material comprises diamond produced by any of a chemical vapour deposition, CVD, process and a high pressure high temperature, HPHT, process. ### Claim 13 (depends on 1) The method according to claim 1, wherein the diamond material is doped. ### Claim 14 (depends on 13) The method according to claim 13, wherein the diamond material is doped with any of nitrogen, boron, phosphorus, and silicon. ### Claim 15 (depends on 1) The method according to claim 1, wherein the damage layer comprises graphitic material. ### Claim 16 (depends on 1) The method according to claim 1, further comprising forming the damage layer by an ion implantation process. ### Claim 17 (depends on 1) The method according to claim 1, further comprising attaching a support structure to a surface of the diamond material prior to the step of electrochemically etching the damage layer, wherein the support structure and the means of attaching the support structure are formed from materials that are substantially inert to a solution in which the electrochemical etching occurs. ### Claim 18 (depends on 1) A diamond product obtained by the method according to claim 1. ### Claim 19 (depends on 18) The diamond product according to claim 18, wherein the diamond product comprises any of single crystal diamond material, polycrystalline diamond material, boron-doped single crystal diamond material and boron-doped polycrystalline diamond material. ### Claim 20 (depends on 18) Use of the diamond product according to claim 18 in any of an optical product, an electronic product and an electrochemical product. ### Claim 21 A diamond product comprising polycrystalline diamond material, wherein the diamond product has an average thickness of no greater than 30 μm and the polycrystalline diamond material has an average lateral grain size as measured by scanning electron microscope imaging of no more than 5 μm. ### Claim 22 (depends on 21) The diamond product according to claim 21, wherein the average lateral grain size is selected from any of greater than 10 μm, greater than 15 μm, and greater than 20 μm. ### Claim 23 A composite body comprising a single crystal diamond plate having an average thickness of no more than 50 μm, and a support structure attached to a surface of the single crystal diamond plate by a glue that is substantially inert to ions capable of forming radicals during electrolysis. ### Claim 24 (depends on 23) The composite body according to claim 23, wherein the glue comprises an epoxy. ### Claim 25 (depends on 23) The composite body according to claim 23, wherein the single crystal diamond plate has an average thickness selected from any of no more than 25 μm, no more than 10 μm, no more than 5 μm and no more than 1 μm.