# US 2021/0241934 A1 · CRYSTAL AND SUBSTRATE OF CONDUCTIVE GaAs, AND METHOD FOR FORMING THE SAME > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241934 A1 - Document ID: US20210241934A1 - Status: Published application - Kind: A1 - Application number: 17/233,845 - Filed: 2021-04-19 - Published: 2021-08-05 - Earliest claimed: 2009-01-20 - Assignees: Sumitomo Electric Industries, Ltd. - Applicants: Sumitomo Electric Industries, Ltd. - Inventors: Takashi Sakurada; Tomohiro Kawase - Web page: https://patentgrep.com/patent/US20210241934A1 ## CPC - H01B 1/02: mainly consisting of metals or alloys - C22F 1/16: of other metals or alloys based thereon - C30B 11/00: Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method (C30B13/00, C30B15/00, C30B17/00, C30B19/00 take precedence; under a protective fluid C30B27/00) - C30B 29/42: Gallium arsenide - C30B 33/00: After-treatment of single crystals or homogeneous polycrystalline material with defined structure (C30B31/00 takes precedence) - C30B 33/02: Heat treatment (C30B33/04, C30B33/06 take precedence) - Y10T 428/24355: Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] - H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K}) - C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00) - 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 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract An electrically conductive GaAs crystal has an atomic concentration of Si more than 1×1017 cm−3, wherein density of precipitates having sizes of at least 30 nm contained in the crystal is at most 400 cm−2. In this case, it is preferable that the conductive GaAs crystal has a dislocation density of at most 2×10−2 cm2 or at least 1×10−3 cm2. ## Claims ### Claim at position 1 1-6. (canceled) ### Claim at position 2 7: A conductive GaAs single crystal substrate cut from a conductive GaAs single crystal, comprising: a polished mirror surface; an atomic concentration of Si being more than 1×1017 cm−3; and a density of precipitates having sizes of at least 30 nm being at most 400 cm−2; wherein on the polished mirror surface a density of microscopic defects having sizes of at least 0.265 μm measured by a surface particle inspection device is at most 0.3 cm−2. ### Claim at position 3 (depends on 7) 8: The conductive GaAs single crystal substrate according to claim 7, wherein the density of precipitates having sizes of at least 30 nm contained in the substrate is at most 300 cm−2. ### Claim at position 4 (depends on 8) 9: The conductive GaAs single crystal substrate according to claim 8, wherein in the mirror surface the density of microscopic defects having sizes of at least 0.265 μm measured by the surface particle inspection device is at most 0.1 cm−2. ### Claim at position 5 (depends on 7) 10: The conductive GaAs single crystal substrate according to claim 7, wherein the density of precipitates having sizes of at least 30 nm contained in the substrate is at most 100 cm−2 and in the mirror surface the density of microscopic defects having sizes of at least 0.265 μm measured by the surface particle inspection device is at most 0.1 cm−2. ### Claim at position 6 (depends on 7) 11: The conductive GaAs single crystal substrate according to claim 7, wherein the density of precipitates is measured by an infrared-ray scattering. ### Claim at position 7 (depends on 7) 12: The conductive GaAs single crystal substrate according to claim 7, wherein a dislocation density of the substrate is at most 5×102 cm−2 or at least 1×103 cm−2. ### Claim at position 8 (depends on 12) 13: The conductive GaAs single crystal substrate according to claim 12, wherein the dislocation density of the substrate is at most 2×102 cm−2. ### Claim at position 9 (depends on 7) 14: The conductive GaAs single crystal substrate according to claim 7, wherein a diameter of the substrate is 4-inch. ### Claim at position 10 (depends on 7) 15: The conductive GaAs single crystal substrate according to claim 7, wherein a diameter of the substrate is 6-inch. ### Claim at position 11 (depends on 7) 16: The conductive GaAs single crystal substrate according to claim 7, wherein the substrate is for a laser device. ### Claim at position 12 (depends on 7) 17: The conductive GaAs single crystal substrate according to claim 7, further comprising an epitaxial layer stacked thereon. ### Claim at position 13 (depends on 17) 18: The conductive GaAs single crystal substrate according to claim 17, wherein a dislocation density of the substrate is at most 5×102 cm−2 or at least 1×103 cm−2. ### Claim at position 14 (depends on 17) 19: The conductive GaAs single crystal substrate according to claim 17, wherein a dislocation density of the substrate is at most 2×102 cm−2. ### Claim at position 15 (depends on 17) 20: The conductive GaAs single crystal substrate according to claim 17, wherein a diameter of the substrate is 4-inch. ### Claim at position 16 (depends on 17) 21: The conductive GaAs single crystal substrate according to claim 17, wherein a diameter of the substrate is 6-inch. ### Claim at position 17 (depends on 17) 22: The conductive GaAs single crystal substrate according to claim 17, wherein the substrate is for a laser device. ### Claim at position 18 (depends on 7) 23: A laser device comprising: the conductive GaAs single crystal substrate according to claim 7; and an epitaxial layer stacked on the conductive GaAs single crystal substrate. ### Claim at position 19 (depends on 23) 24: The laser device according to claim 23, wherein a dislocation density of the substrate is at most 5×102 cm−2 or at least 1×103 cm−2. ### Claim at position 20 (depends on 23) 25: The laser device according to claim 23, wherein a dislocation density of the substrate is at most 2×102 cm−2.