# US 8,771,560 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 8,771,560 B2 - Document ID: US8771560B2 - Status: Granted - Kind: B2 - Application number: 12/034,345 - Filed: 2008-02-20 - Published: 2008-08-28 - Granted: 2014-07-08 - Earliest claimed: 2005-07-01 - Assignees: Freiberger Compound Materials GmbH - Applicants: Ulrich Kretzer; Stefan Eichler; Thomas Bünger - Inventors: Ulrich Kretzer; Stefan Eichler; Thomas Bünger - Web page: https://patentgrep.com/patent/US8771560B2 ## 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 An n-type III-V semiconductor single crystal ingot having a diameter of at least about 100 mm, wherein the ingot is produced by a process of vertically directed solidification of a melt of semiconductor material, in which process the semiconductor melt was covered by a cover melt, and wherein the ingot satisfies the following conditions within its cylindrical part at each axial position corresponding to mass fractions g of solidified melt between 0.1 and 0.9: a concentration of an electrical conductivity-generating dopant in a range of about 1×1018 atoms/cm3 to 5×1019 atoms/cm3, a concentration of an impurity, which is present due to the manufacturing process for the single crystal from the cover melt, in a range of about 1×1017 atoms/cm3 to 5×1018 atoms/cm3, and an electrical conductivity of at least about 250 Siemens/cm, and/or a specific resistivity of at most about 4×10−3 Ωcm. ### Claim 2 (depends on 1) An n-type III-V semiconductor single crystal ingot according to claim 1, wherein the III-V semiconductor single crystal has an electrical conductivity of at least about 250 Siemens/cm and a specific resistivity of at most about 4×10−3 Ωcm. ### Claim 3 (depends on 1) An n-type III-V semiconductor single crystal ingot according to claim 1, wherein the concentration of the electrical conductivity-generating dopant is in a range of about 2×1018 atoms/cm3 to 1×1019 atoms/cm3, and/or the concentration of an impurity, which is present due to the manufacturing process, is in a range of about 1×1017 atoms/cm3 to 3.5×1018 atoms/cm3. ### Claim 4 A III-V semiconductor single crystal ingot having a diameter of at least about 100 mm, wherein the ingot is produced by a process of vertically directed solidification of a melt of semiconductor material, wherein the semiconductor melt is covered by a cover melt, and wherein the ingot satisfies the following conditions within its cylindrical part at each axial position corresponding to mass fractions g of solidified melt between 0.1 and 0.9: a concentration of an electrical conductivity-generating dopant in a range of about 1×1018 atoms/cm3 to 5×1019 atoms/cm3; a concentration of an impurity that is present due to the manufacturing process for the single crystal from the cover melt is contained at a concentration in a range of about 1×1017 atoms/cm3 to 5×1018 atoms/cm3; and a charge carrier concentration of at least about 1.0×1018 cm−3, wherein the Hall mobility, determined according to ASTM F76-86, for the case of a charge carrier concentration of 1.0 to 1.2×1018 cm−3 is higher than 2,100 cm2/Vs, and for the case of a charge carrier concentration of higher than 1.2×1018 cm−3 is higher than 1,900 cm2/Vs. ### Claim 5 (depends on 4) A III-V semiconductor single crystal ingot according to claim 4, wherein in a range of a charge carrier concentration of 1.3 to 1.8×1018 cm−3, the Hall mobility is at least 2,000 cm2/Vs. ### Claim 6 (depends on 4) A III-V semiconductor single crystal ingot according to claim 4, wherein the concentration of the electrical conductivity-generating dopant is in a range of about 1.5×1018 atoms/cm3 to 1×1019 atoms/cm3. ### Claim 7 (depends on 6) A III-V semiconductor single crystal ingot according to claim 6, wherein the dopant comprises silicon, and/or wherein the impurity comprises Boron. ### Claim 8 (depends on 4) A III-V semiconductor single crystal ingot according to claim 4, wherein the III-V semiconductor compound comprises GaAs. ### Claim 9 (depends on 4) A III-V semiconductor single crystal ingot according to claim 4, which is produced according to a VGF or a VB process utilizing a cover melt. ### Claim 10 (depends on 4) A III-V semiconductor single crystal ingot according to claim 4, wherein the crystal is produced by the process of 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 an amount of dopant to the semiconductor material prior to formation of the semiconductor single crystal, to adjust an electrical conductivity in the semiconductor single crystal, wherein at least a portion of the 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 11 (depends on 1) A substrate wafer, formed from an n-type III-V semiconductor single crystal ingot according to claim 1. ### Claim 12 (depends on 4) A substrate wafer, formed from a III-V semiconductor single crystal ingot according to claim 4. ### Claim 13 (depends on 1) The semiconductor of claim 1, wherein the semiconductor single crystal ingot is produced by: 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 an amount of dopant to the semiconductor material prior to formation of the semiconductor single crystal, to adjust an electrical conductivity in the semiconductor single crystal; and wherein at least a portion of the amount of dopant is added to the semiconductor melt (a) after the growth of semiconductor single crystal onto the seed crystal has started, or (b) after at least partial solidification of the semiconductor single crystal in the tapered portion of the crucible.