# US 10,309,036 B2 · Method for manufacturing group-III nitride semiconductor crystal substrate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,036 B2 - Document ID: US10309036B2 - Status: Granted - Kind: B2 - Application number: 15/555,004 - Filed: 2016-02-18 - Published: 2018-02-08 - Granted: 2019-06-04 - Earliest claimed: 2015-03-03 - Assignees: Osaka University; Sumitomo Chemical Company, Limited - Applicants: Osaka University; Sumitomo Chemical Company, Limited - Inventors: Yusuke Mori; Masashi Yoshimura; Mamoru Imade; Masatomo Shibata; Takehiro Yoshida - Web page: https://patentgrep.com/patent/US10309036B2 ## CPC - C30B 19/02: using molten solvents, e.g. flux - C30B 25/20: the substrate being of the same materials as the epitaxial layer - C30B 29/406: {Gallium nitride} - H10P 14/20: of semiconductor materials - H10P 14/24: using chemical vapour deposition [CVD] - H10P 14/263: {using melted materials} - H10P 14/265: {using solutions} - H10P 14/2908: {Nitrides} - H10P 14/2921: {being crystalline insulating materials} - H10P 14/2926: {Crystal orientations} - H10P 14/3216: {Nitrides} - H10P 14/3258: {Crystal orientation} - H10P 14/3416: {Nitrides} - H10P 14/3466: {Crystal orientation} - H10P 90/129: {by polishing} - 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 ## Abstract A method for manufacturing a group III nitride semiconductor crystal substrate includes providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid phase growth method, and homoepitaxially growing a group III nitride single crystal by a vapor phase growth method on a principal surface of the seed crystal substrate. The principal surface of the seed crystal substrate is a +c-plane, and the seed crystal substrate has an atomic oxygen concentration of not more than 1×1017 cm−3 in a crystal near the principal surface over an entire in-plane region thereof. ## Claims ### Claim 1 A method for manufacturing a group III nitride semiconductor crystal substrate, the method comprising: providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid phase growth method; and homoepitaxially growing a group III nitride single crystal by a vapor phase growth method on a principal surface of the seed crystal substrate, wherein the principal surface of the seed crystal substrate includes a +c-plane, wherein an entirety of a surface of the seed crystal substrate has an atomic oxygen concentration of not more than 1×1017 cm−3 in a crystal near the principal surface over an entire in-plane region thereof, and wherein the seed crystal substrate comprises, at least on the principal surface, a crystalline region grown in a state that a flat growth interface in a two-dimensional growth mode is maintained during crystal growth. ### Claim 2 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein the group III nitride single crystal grown on the seed crystal substrate by the vapor phase growth method has an atomic oxygen concentration of not more than 1×1017 cm−3 in the crystal. ### Claim 3 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein the seed crystal substrate comprises a crystal that is grown while gradually transitioning a shape of a growth interface during the crystal growth, from an uneven growth interface in a three-dimensional growth mode to the flat growth interface in the two-dimensional growth mode. ### Claim 4 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein at least the principal surface of the seed crystal substrate is mirror-polished. ### Claim 5 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein an average dislocation density on the surface of the seed crystal substrate is not more than 1×107 cm−2. ### Claim 6 A method for manufacturing a group III nitride semiconductor crystal substrate, the method comprising: providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid phase growth method; and homoepitaxially growing a group III nitride single crystal by a vapor phase growth method on a principal surface of the seed crystal substrate, wherein the principal surface the seed crystal substrate includes a +c-plane, wherein an entirety of a surface of the seed crystal substrate has an atomic oxygen concentration of not more than 1×107 cm−3 in a crystal near the principal surface over an entire in-lane region thereof, and wherein a c-plane of the seed crystal substrate has inside the crystal a warpage that is concave surface-shaped toward the principal surface. ### Claim 7 (depends on 6) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 6, wherein the seed crystal substrate has a diameter of not less than 50 mm, and wherein the c-plane thereof has, inside the crystal, a warpage that is concave surface-shaped toward the principal surface and not less than 5 m in a curvature radius. ### Claim 8 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein the liquid phase growth method includes a flux method. ### Claim 9 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein the vapor phase growth method includes a hydride vapor phase epitaxy (HVPE) method, and wherein the group III nitride single crystal, having a larger thickness than the seed crystal substrate, is homoepitaxially grown on the seed crystal substrate by the HVPE method. ### Claim 10 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein the seed crystal substrate is made using, as a starting substrate, a seed crystal-forming substrate or a point-seed substrate with a plurality of group III nitride seed crystals formed thereon. ### Claim 11 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein no polarity-reversal region is present at least on the principal surface of the seed crystal substrate. ### Claim 12 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein at least one or more group III nitride single crystal free-standing substrates are made from the group III nitride single crystal grown by the vapor phase growth method. ### Claim 13 (depends on 1) The method for manufacturing a group III nitride semiconductor crystal substrate according to claim 1, wherein the group III nitride comprises GaN. ### Claim 14 A method for manufacturing a group III nitride semiconductor crystal substrate the method comprising: providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid phase growth method; and homoepitaxially growing a group III nitride single crystal by a vapor phase growth method on a principal surface of the seed crystal substrate, wherein the principal surface of the seed crystal substrate includes a +c-plane, wherein an entirety of a surface of the seed crystal substrate has an atomic oxygen concentration of not more than 1×1017 cm−3 in a crystal near the principal surface over an entire in-plane region thereof, and wherein a growth surface includes a flat c-plane in the liquid phase growth method. ### Claim 15 A method for manufacturing a group III nitride semiconductor crystal substrate, the method comprising: providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid chase growth method; and homoepitaxially growing a group III nitride single crystal by a vapor phase growth method on a principal surface of the seed crystal substrate, wherein the principal surface of the seed crystal substrate includes a +c-plane, wherein an entirety of a surface of the seed crystal substrate has a atomic oxygen concentration of not more than 1×107 cm−3 in a crystal near the principal surface over an entire in-plane region thereof, and wherein an incorporated oxygen concentration in the crystal varies depending on a plane orientation of a crystal growth interface. ### Claim 16 A method for manufacturing a group III nitride semiconductor crystal substrate the method comprising: providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid phase growth method; and homoepitaxially growing a group III nitride single crystal by a vapor phase growth method on a principal surface of the seed crystal substrate, wherein the principal surface of the seed crystal substrate includes a +c-plane, wherein an entirety of a surface of the seed crystal substrate has an atomic oxygen concentration of not more than 1×1017 cm−3 in a crystal near the principal surface over an entire in-region thereof, and wherein the atomic oxygen concentration is within a range from 3×1016 cm−3 to 5×1016 cm−3. ### Claim 17 A method for manufacturing a group III nitride semiconductor crystal substrate, the method comprising: providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid phase growth method; and homoepitaxially growing a group III nitride single crystal by a vapor vase growth method on a principal surface of the seed crystal substrate, wherein the principal surface of the seed crystal substrate includes a +c-plane, wherein an entirety of a surface of the seed crystal substrate has an atomic oxygen concentration of not more than 1×1017 cm−3 in a crystal near the principal surface over an entire in-plane region thereof, and wherein the near the principal surface includes a region within 20 μm in depth from the principal surface. ### Claim 18 A method for manufacturing group III nitride semiconductor crystal substrate, the method comprising: providing, as a seed crystal substrate, a group III nitride single crystal grown by a liquid phase growth method; and homoepitaxially growing a group III nitride single crystal by vapor has growth method on a principal surface of the seed crystal substrate, wherein the principal surface of the seed crystal substrate includes a +c-plane, wherein entirety of a surface of the seed crystal substrate has an atomic oxygen concentration of not more than 1×1017 cm−3 in a crystal near the principal surface over an entire in-plane region thereof, and wherein a dislocation density in the group III nitride single crystal grown by the vapor phase growth method is not more than 1×107 cm−2. ### Claim 19 A method for manufacturing a group III nitride semiconductor crystal substrate, the method comprising: providing, as a seed crystal substrate a group III nitride single crystal grown by a liquid phase growth method; and homoepitaxially growing a group III nitride single crystal by a vapor phase growth method on a principal surface of the seed crystal substrate, wherein the principal surface of the seed crystal substrate includes a +c-plane, wherein an entirety of a surface of the seed crystal substrate has an atomic oxygen concentration of not more than 1×1017 cm−3 in a crystal near the principal surface over an entire in-plane region thereof, and wherein the seed crystal substrate is free of a region of an N-polar face with reversed polarity partially emerged on a Ga-polar face of the principal surface.