# US 7,410,540 B2 · Process for the manufacture of doped semiconductor single crystals, and III-V semiconductor single crystal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,410,540 B2 - Document ID: US7410540B2 - Status: Granted - Kind: B2 - Application number: 11/478,450 - Filed: 2006-06-30 - Published: 2007-01-18 - Granted: 2008-08-12 - Earliest claimed: 2005-07-01 - Assignees: Freiberger Compound Materials GmbH - Inventors: Ulrich Kretzer; Stefan Eichler; Thomas Bünger - Web page: https://patentgrep.com/patent/US7410540B2 ## CPC - C30B 11/04: adding crystallising materials or reactants forming it in situ to the melt - 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 11/002: {Crucibles or containers for supporting the melt} - C30B 11/14: characterised by the seed, e.g. its crystallographic orientation - C30B 29/40: AIIIBV compounds {wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi} - C30B 29/42: Gallium arsenide - 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 In a process for manufacturing doped semiconductor single crystal comprises solidifying in a crucible, the amount of dopant is added into the semiconductor melt after the beginning of the crystal growth onto the seed crystal, or after at least partial solidification of the semiconductor single crystal in a conical or tapered portion of the crucible. Dopant may be partially added in advance into the crucible, with the remainder added into the semiconductor melt as described. Type III-V semiconductor single crystals or wafers having a diameter of at least about 100 mm, can be prepared having an electrical conductivity of at least about 250 Siemens/cm, and/or an electric resistivity of at most about 4×10−3 Ωcm, and/or a significantly improved ratio of hall mobility to charge carrier concentration. ## Claims ### Claim 1 A process for manufacturing a semiconductor single crystal doped by a dopant, comprising: solidifying a melt of semiconductor material using a seed crystal of the same semiconductor material as the semiconductor single crystal to be manufactured, in a crucible comprising a tapered portion and a cylindrical portion; and adding a first amount of dopant to the semiconductor material prior to formation of the single crystal, to adjust an electrical conductivity in the semiconductor single crystal, wherein at least a portion of the first amount of dopant is added to the semiconductor melt (a) after growth of semiconductor single crystal onto the seed crystal has started, or (b) after at least partial solidification of semiconductor single crystal in the tapered portion of the crucible. ### Claim 2 (depends on 1) A process according to claim 1, comprising adding said dopant in at least two steps, including a first step of adding a partial amount into the crucible in advance of (a) or (b), and a second step of adding a second amount to the semiconductor melt according to (a) or (b). ### Claim 3 (depends on 2) A process according to claim 2, wherein the partial amount of dopant added in said first step comprises up to ⅔ of said first amount of the dopant. ### Claim 4 (depends on 3) A process according to claim 3, wherein said partial amount comprises ⅕ to ½ of said first amount of the dopant. ### Claim 5 (depends on 1) A process according to claim 1, wherein the concentration of dopant in the tapered portion of the semiconductor single crystal is at most about 1×1018 atoms/cm3, and/or the concentration of dopant in the cylindrical portion of the semiconductor single crystal is higher than about 6×1017 atoms/cm3. ### Claim 6 (depends on 1) A process according to claim 1, further comprising covering the semiconductor melt by a cover melt, and wherein the concentration of impurity deriving from the cover melt is below about 5×1018 atoms/cm3 within the cylindrical portion of the semiconductor single crystal. ### Claim 7 (depends on 6) A process according to claim 6, wherein the cover melt comprises a boron oxide melt, and the impurity derived therefrom comprises boron. ### Claim 8 (depends on 1) A process according to claim 1, wherein the produced semiconductor single crystal is a single crystal of a III-V compound semiconductor. ### Claim 9 (depends on 8) A process according to claim 8, wherein the produced single crystal comprises gallium arsenide as the main component. ### Claim 10 (depends on 1) A process according to claim 1, wherein the produced semiconductor single crystal has a high electrical conductivity of n- or p-type. ### Claim 11 (depends on 10) A process according to claim 10, wherein the produced semiconductor single crystal has an electrical conductivity of at least about 250 Siemens/cm, and/or an electric resistivity of at most about 4×10−3Ωcm. ### Claim 12 (depends on 1) A process according to claim 1, wherein the dopant is added as a solid dopant. ### Claim 13 (depends on 1) A process according to claim 1, wherein the dopant comprises silicon in elemental or chemically-bound form. ### Claim 14 (depends on 1) A process according to claim 1, which comprises a VGF or a VB process.