Patents Assigned to AXT, Inc.
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Publication number: 20180259277Abstract: A charging handle includes a shaft, a front end that is operably coupled to a firearm bolt carrier, and a head that is located on an opposite end of the shaft from the front end. One or more ventilation features may be located in a first half of the length of the shaft proximate to the front end of the charging handle to prohibit exhaust that travels from the front end along the upper surface and/or side surfaces of the shaft from reaching the rear of the firearm and/or the head of the charging handle.Type: ApplicationFiled: May 14, 2018Publication date: September 13, 2018Applicant: AXTS, Inc.Inventor: Joshua A. UNDERWOOD
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Patent number: 9995543Abstract: A charging handle includes a shaft, a front end that is operably coupled to a firearm bolt carrier, and a head that is located on an opposite end of the shaft from the front end. One or more ventilation features may be located in a first half of the length of the shaft proximate to the front end of the charging handle to prohibit exhaust that travels from the front end along the upper surface and/or side surfaces of the shaft from reaching the rear of the firearm and/or the head of the charging handle.Type: GrantFiled: October 12, 2016Date of Patent: June 12, 2018Assignee: AXTS, INC.Inventor: Joshua A. Underwood
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Patent number: 8647433Abstract: Systems and methods are disclosed for crystal growth including features of reducing micropit cavity density in grown germanium crystals. In one exemplary implementation, there is provided a method of inserting an ampoule with raw material into a furnace having a heating source, growing a crystal using a vertical growth process wherein movement of a crystallizing temperature gradient relative to the raw material/crucible is achieved to melt the raw material, and growing, at a predetermined crystal growth length, the material to achieve a monocrystalline crystal, wherein monocrystalline ingots having reduced micro-pit densities are reproducibly provided.Type: GrantFiled: December 13, 2009Date of Patent: February 11, 2014Assignee: AXT, Inc.Inventors: Weiguo Liu, Xiao Li
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Patent number: 8506706Abstract: Systems, methods, and substrates directed to growth of monocrystalline germanium (Ge) crystals are disclosed. In one exemplary implementation, there is provided a method for growing a monocrystalline germanium (Ge) crystal. Moreover, the method may include loading first raw Ge material into a crucible, loading second raw Ge material into a container for supplementing the Ge melt material, sealing the crucible and the container in an ampoule, placing the ampoule with the crucible into a crystal growth furnace, as well as melting the first and second raw Ge material and controlling the crystallizing temperature gradient of the melt to reproducibly provide monocrystalline germanium ingots with improved/desired characteristics.Type: GrantFiled: September 5, 2009Date of Patent: August 13, 2013Assignee: AXT, IncInventor: Weiguo Liu
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Patent number: 8361225Abstract: Systems and methods of manufacturing wafers are disclosed using a low EPD crystal growth process and a wafer annealing process are provided resulting in III-V/GaAs wafers that provide higher device yields from the wafer. In one exemplary implementation, there is provided a method of manufacturing a group III based material with a low etch pit density (EPD). Moreover, the method includes forming polycrystalline group III based compounds, and performing vertical gradient freeze crystal growth using the polycrystalline group III based compounds. Other exemplary implementations may include controlling temperature gradient(s) during formation of the group III based crystal to provide very low etch pit density.Type: GrantFiled: August 10, 2011Date of Patent: January 29, 2013Assignee: AXT, Inc.Inventors: Weiguo Liu, Morris S. Young, M. Hani Badawi
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Patent number: 8318042Abstract: Chemical polishing solutions and methods are disclosed for the chemical polishing of GaAs wafers. An exemplary chemical polishing solution consistent with the innovations herein may comprise dichloroisocyanurate, sulfonate, acid pyrophosphate, bicarbonate and carbonate. An exemplary chemical polishing method may comprise polishing a wafer in a chemical polishing apparatus in the presence of such a chemical polishing solution. Chemical polishing solutions and methods herein make it possible, for example, to improve wafer quality, decrease costs, and/or reduce environmental pollution.Type: GrantFiled: September 29, 2009Date of Patent: November 27, 2012Assignee: AXT Inc.Inventors: Tan Kaixie, Gu Yan, Wang Yuanli
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Patent number: 8231727Abstract: Systems and methods are disclosed for crystal growth using VGF and VB growth processes to reduce body lineage. In one exemplary embodiment, there is provided a method of inserting an ampoule with raw material into a furnace having a heating source, growing a crystal using a vertical gradient freeze process wherein the crystallizing temperature gradient is moved relative to the crystal and/or furnace to melt the raw material and reform it as a monocrystalline compound, and growing the crystal using a vertical Bridgman process on the wherein the ampoule/heating source are moved relative each other to continue to melt the raw material and reform it as a monocrystalline compound.Type: GrantFiled: April 17, 2008Date of Patent: July 31, 2012Assignee: AXT, Inc.Inventors: Weiguo Liu, A. Grant Elliot
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Publication number: 20110293890Abstract: Systems and methods of manufacturing wafers are disclosed using a low EPD crystal growth process and a wafer annealing process are provided resulting in III-V/GaAs wafers that provide higher device yields from the wafer. In one exemplary implementation, there is provided a method of manufacturing a group III based material with a low etch pit density (EPD). Moreover, the method includes forming polycrystalline group III based compounds, and performing vertical gradient freeze crystal growth using the polycrystalline group III based compounds. Other exemplary implementations may include controlling temperature gradient(s) during formation of the group III based crystal to provide very low etch pit density.Type: ApplicationFiled: August 10, 2011Publication date: December 1, 2011Applicant: AXT, Inc.Inventors: Weiguo Liu, Morris S. Young, M. Hani Badawi
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Publication number: 20110143091Abstract: Systems and methods are disclosed for crystal growth including features of reducing micropit cavity density in grown germanium crystals. In one exemplary implementation, there is provided a method of inserting an ampoule with raw material into a furnace having a heating source, growing a crystal using a vertical growth process wherein movement of a crystallizing temperature gradient relative to the raw material/crucible is achieved to melt the raw material, and growing, at a predetermined crystal growth length, the material to achieve a monocrystalline crystal, wherein monocrystalline ingots having reduced micro-pit densities are reproducibly provided.Type: ApplicationFiled: December 13, 2009Publication date: June 16, 2011Applicant: AXT, INC.Inventors: Weiguo Liu, Xiao Li
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Publication number: 20100176336Abstract: Chemical polishing solutions and methods are disclosed for the chemical polishing of GaAs wafers. An exemplary chemical polishing solution consistent with the innovations herein may comprise dichloroisocyanurate, sulfonate, acid pyrophosphate, bicarbonate and carbonate. An exemplary chemical polishing method may comprise polishing a wafer in a chemical polishing apparatus in the presence of such a chemical polishing solution. Chemical polishing solutions and methods herein make it possible, for example, to improve wafer quality, decrease costs, and/or reduce environmental pollution.Type: ApplicationFiled: September 29, 2009Publication date: July 15, 2010Applicant: AXT, INC.Inventors: Tan Kaixie, Gu Yan, Wang Yuanli
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Publication number: 20100116196Abstract: Systems, methods, and substrates directed to growth of monocrystalline germanium (Ge) crystals are disclosed. In one exemplary implementation, there is provided a method for growing a monocrystalline germanium (Ge) crystal. Moreover, the method may include loading first raw Ge material into a crucible, loading second raw Ge material into a container for supplementing the Ge melt material, sealing the crucible and the container in an ampoule, placing the ampoule with the crucible into a crystal growth furnace, as well as melting the first and second raw Ge material and controlling the crystallizing temperature gradient of the melt to reproducibly provide monocrystalline germanium ingots with improved/desired characteristics.Type: ApplicationFiled: September 5, 2009Publication date: May 13, 2010Applicant: AXT, INC.Inventor: Weiguo Liu
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Publication number: 20100001288Abstract: A method for manufacturing wafers using a low EPD crystal growth process and a wafer annealing process is provided that results in GaAs/InGaP wafers that provide higher device yields from the wafer.Type: ApplicationFiled: July 20, 2009Publication date: January 7, 2010Applicant: AXT, Inc.Inventors: Weiguo Liu, Morris S. Young, M. Hani Badawi
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Patent number: 7566641Abstract: A method for manufacturing wafers using a low EPD crystal growth process and a wafer annealing process is provided that results in GaAs/InGaP wafers that provide higher device yields from the wafer.Type: GrantFiled: May 9, 2007Date of Patent: July 28, 2009Assignee: AXT, Inc.Inventors: Weiguo Liu, Morris S. Young, M. Hani Badawi
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Publication number: 20090179015Abstract: A system and method for adjustable laser mark depth is provided. In one embodiment, the system is used in Nd—YAG laser marker for wafer processing in the semiconductor industry, with smart control of the mark depth and expanded work range between the deep mark and the light mark.Type: ApplicationFiled: January 15, 2008Publication date: July 16, 2009Applicants: AXT, INC., GSI Technology, Inc.Inventors: Xiaodong Zhao, Yingjie Geng
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Publication number: 20060183329Abstract: An apparatus and method of treating multiple wafers to reduce the density of impurities as well as to improve the uniformity of substrate electrical characteristics without any thermal stress. The wafers are chemically treated, and heat treated in a sealed reaction tube under arsenic overpressure with a controlled thermal profile to heat the wafers. The thermal profile controls temperature of different zones inside of a furnace containing the sealed reaction tube. Impurities of the wafers are dissolved, and are out-diffused from the inner portions to the outer portions of the wafers.Type: ApplicationFiled: March 2, 2004Publication date: August 17, 2006Applicant: AXT, Inc.Inventors: Charles Leung, David Zhang, Morris Young
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Patent number: 6896729Abstract: Group III-V, II-VI and related monocrystalline compounds are grown with a rigid support of a sealed ampoule, carbon doping and resistivity control, and thermal gradient control in a crystal growth furnace. A support cylinder provides structural support for the combined sealed ampoule crucible assembly, while low-density insulating material inside the support cylinder deters convection and conduction heating. Radiation channels penetrating the low-density material provide pathways for radiation heating into and out of the seed well and transition regions of the crystal growth crucible. A hollow core in the insulation material directly beneath the seed well provides cooling in the center of the growing crystal, which enables uniform, level growth of the crystal ingot and a flat crystal-melt interface which results in crystal wafers with uniform electrical properties.Type: GrantFiled: July 3, 2002Date of Patent: May 24, 2005Assignee: AXT, Inc.Inventors: Xiao Gordon Liu, Wei Guo Liu
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Patent number: 6650018Abstract: A high power, high luminous flux light emitting diode (LED) comprises a substrate, a light-emitting structure, a first electrode and a second electrode. The LED has a top surface layout design in which the first electrode has a number of legs extending in one direction, and the second electrode has a number of legs extending in the opposite direction. At least portions of the legs of the first electrode are interspersed with and spaced apart from portions of the legs of the second electrode. This provides a configuration that enhances current spreading along the length of the legs of both electrodes.Type: GrantFiled: May 24, 2002Date of Patent: November 18, 2003Assignee: AXT, Inc.Inventors: Yongsheng Zhao, William W. So, Kevin Y. Ma, Chyi S. Chern, Heng Liu, Eugene J. Ruddy
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Patent number: 6643304Abstract: A Gallium Nitride based Light Emitting Diode (LED) includes both a transparent substrate and a window for exiting light generated by the LED. Useful amounts of light may be utilized at the face of the window or at the face of the transparent substrate. An external optical reflector is formed directly on the external face of the LED which is not currently being used to exit useful light. If light from the window is being utilized, a Distributed Bragg Reflector (DBR) is formed directly on the “backside” of the substrate. However, if light through the substrate is being utilized, a Distributed Bragg Reflector is formed directly on the light emitting portion of the window.Type: GrantFiled: July 26, 2000Date of Patent: November 4, 2003Assignee: AXT, Inc.Inventors: John Chen, Bingwen Liang, Robert Shih
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Publication number: 20030172870Abstract: An apparatus for producing large diameter monocrystalline Group III-V, II-VI compounds that have reduced crystal defect density, improved crystal growth yield, and improved bulk material characteristics. The apparatus comprises a crucible or boat, an ampoule that contains the crucible or boat, a heating unit disposed about the ampoule, and a liner disposed between the heating unit and the ampoule. The liner is preferably composed of a quartz material. When the liner and the ampoule are made of the same material, such as quartz, the thermal expansion coefficients of the liner and ampoule are the same, which significantly increases the lifetime of the liner and the single-crystal yield.Type: ApplicationFiled: March 14, 2002Publication date: September 18, 2003Applicant: AXT, Inc.Inventors: Xiao Gordon Liu, Weiguo Liu
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Patent number: D776222Type: GrantFiled: February 13, 2015Date of Patent: January 10, 2017Assignee: AXTS INC.Inventor: Joshua A. Underwood