Patents by Inventor Chandra Khattak

Chandra Khattak has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20120055396
    Abstract: A system and method for growing crystals is described. The system includes a crucible, a shaft adapted to support the crucible, and an intermediate material between the crucible and the shaft having a coating directly applied to contact surfaces of the crucible and the shaft. The coating includes a compound, such as, a carbide, nitride, oxide, or boride. The method for growing a crystal includes providing an intermediate material between contact surfaces between a shaft and a crucible supported by the shaft prior to melting a charge material in the crucible.
    Type: Application
    Filed: October 21, 2011
    Publication date: March 8, 2012
    Applicant: ADVANCED RENEWABLEENERGY COMPANY LLC
    Inventors: Govindhan Dhanaraj, Chandra Khattak, Ben Korzeniowski, Carl Richard Schwerdtfeger, JR., Raj Shetty
  • Publication number: 20110044842
    Abstract: A method for making bulk silicon material consisting of silicon pellets for making silicon ingots from an agglomerate-free source of high purity, ultra fine silicon powder includes feeding a controlled amount of silicon powder into a pellet die and dry compacting the powder at ambient temperature with pressure to produce a pellet that has a density of about 50-85% of the theoretical density of elemental silicon, a weight within a range of about 1.0 gram to about 3.0 grams, a diameter in the range of 10 mm to 20 mm and preferably of about 14 mm, and a height in the range of 5 mm to 15 mm and preferably of about 10 mm.
    Type: Application
    Filed: October 21, 2010
    Publication date: February 24, 2011
    Applicant: GT SOLAR INCORPORATED
    Inventors: Kedar P. Gupta, Yuepeng Wan, Santhana Raghavan Parthasarathy, Chandra Khattak
  • Publication number: 20080035051
    Abstract: To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.
    Type: Application
    Filed: October 19, 2007
    Publication date: February 14, 2008
    Applicant: CRYSTAL SYSTEMS, INC.
    Inventors: Frederick SCHMID, Chandra KHATTAK, David JOYCE
  • Publication number: 20070251455
    Abstract: A method and process for the production of bulk polysilicon by chemical vapor deposition (CVD) where conventional silicon “slim rods” commonly used in Siemens-type reactors are replaced with shaped silicon filaments of similar electrical properties but larger surface areas, such as silicon tubes, ribbons, and other shaped cross sections. Silicon containing gases, such as chlorosilane or silane, are decomposed and form a silicon deposit on the hot surfaces of the filaments The larger starting surface areas of these filaments ensures a higher production rate without changing the reactor size, and without increasing the number and length of the filaments. Existing reactors need only the adaptation or replacement of filament supports to use the new filaments. The filaments are grown from silicon melt by Edge-defined, Film-fed Growth (EFG) method. This also enables the doping of the filaments and simplification of power supplies for new reactors.
    Type: Application
    Filed: April 28, 2006
    Publication date: November 1, 2007
    Applicant: GT Equipment Technologies, Inc.
    Inventors: Yuepeng Wan, Santhana Parthasarathy, Carl Chartier, Adrian Servini, Chandra Khattak
  • Publication number: 20070148034
    Abstract: A bulk silicon material for making silicon ingots, consisting of silicon pellets, and a method for making the pellets from an agglomerate-free source of high purity, ultra fine silicon powder by feeding a controlled amount of silicon powder into a pellet die, and dry compacting the powder at ambient temperature with pressure to produce a pellet that has a density of about 50-85% of the theoretical density of elemental silicon, a weight within a range of about 1.0 gram to about 3.0 grams, a diameter in the range of 10 mm to 20 mm and preferably of about 14 mm, and a height in the range of 5 mm to 15 mm and preferably of about 10 mm.
    Type: Application
    Filed: January 30, 2007
    Publication date: June 28, 2007
    Applicant: GT SOLAR INCORPORATED
    Inventors: Kedar Gupta, Yuepeng Wan, Santhana Parthasarathy, Chandra Khattak
  • Publication number: 20070044707
    Abstract: To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.
    Type: Application
    Filed: August 25, 2005
    Publication date: March 1, 2007
    Inventors: Frederick Schmid, Chandra Khattak, David Joyce