Patents by Inventor Kedar P. Gupta

Kedar P. Gupta 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: 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
  • Patent number: 7540919
    Abstract: A process for making silicon ingots using a multi-part, reusable, graphite crucible of at least two mold pieces configured for assembly into an open top mold having an interior surface functional as a mold cavity for receiving molten silicon; removing or reducing a prior applied release coating from the interior surface until a uniformly smooth finish is achieved; coating the interior surface with a first layer of release coating comprising silicon nitride; coating the interior surface with a second layer of release coat comprising silica suspended in water; coating the interior surface with a third layer of release coat comprising silicon nitride; curing the release coat on said crucible; casting a silicon ingot in the crucible; and then repeating the prior steps multiple times.
    Type: Grant
    Filed: March 31, 2006
    Date of Patent: June 2, 2009
    Assignee: GT Solar Incorporated
    Inventors: Santhana Raghavan Parthasarathy, Yuepeng Wan, Carl Chartier, Jonathan A Talbott, Kedar P Gupta
  • Patent number: 7175685
    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 silicon powder by feeding a controlled amount of silicon powder that is free of intentional additives and binders into a pellet die, and dry compacting the powder at ambient temperature with pressure to produce a pellet that has a density of about 50–75% of the theoretical density of elemental silicon, a weight within a range of about 1.0 gram to about 3.0 grams and preferably of about 2.3 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: Grant
    Filed: April 15, 2003
    Date of Patent: February 13, 2007
    Assignee: GT Solar Incorporated
    Inventors: Alleppey V Hariharan, Mohan Chandra, Kedar P Gupta
  • Patent number: 6365225
    Abstract: A method and apparatus, and product by process, for the production of bulk polysilicon by a chemical vapor deposition process on a removable tube section. A quartz envelope and base plate form a CVD reactor enclosure, with external radiant heaters providing process heat through the wall of the reactor, and with process gas inlet and outlet ports located in the base plate. A tube section, preferably an EFG silicon tube-section, vertically emplaced on the base plate and capped to close the top is used as the reaction chamber. During the CVD process, deposition occurs on the inside surface of the chamber tube, the inner diameter of the deposit layer becoming increasingly smaller as the yield accumulates. In a two tube reactor, a smaller diameter, vertical middle tube is uniformly spaced and supported inside the chamber tube for fall flow of process gas over and under the middle tube so that deposition occurs on the three exposed tube surfaces.
    Type: Grant
    Filed: August 17, 2000
    Date of Patent: April 2, 2002
    Assignee: G.T. Equipment Technologies, Inc.
    Inventors: Mohan Chandra, Kedar P. Gupta, Jonathan A. Talbott, Ijaz Jafri, Vishwanath Prasad
  • Patent number: 6113473
    Abstract: A slurry recycle process for use in free-abrasive machining operations such as for wire saws used in wafer slicing of ingots, where the used slurry is separated into kerf-rich and abrasive-rich components, and the abrasive-rich component is reconstituted into a makeup slurry. During the process, the average particle size of the makeup slurry is controlled by monitoring the condition of the kerf and abrasive components and making necessary adjustments to the separating force and dwell time of the separator apparatus. Related pre-separator and post separator treatments, and feedback of one or the other separator slurry output components for mixing with incoming used slurry and recirculation through the separator, provide further effectiveness and additional control points in the process.
    Type: Grant
    Filed: April 24, 1998
    Date of Patent: September 5, 2000
    Assignee: G.T. Equipment Technologies Inc.
    Inventors: Michael A. Costantini, Jonathan A. Talbott, Mohan Chandra, Vishwanath Prasad, Allison Caster, Kedar P. Gupta, Philippe Leyvraz
  • Patent number: 6067728
    Abstract: An apparatus and method for drying a microelectronic structure on wafer substrate using supercritical phase gas techniques and a unique pressure vessel locking mechanism. There is lid and a base with an open cavity to contain at least one microelectronic structure on wafer substrate. Clamping the lid to the base uses locking clamp rings with open jaws large to partially enclose the edge of the vessel. The clamp rings are supported symmetrically about the sides of the vessel. The rings are adjusted between an open position where the rings are clear of the vessel and a locking position where the jaws partially enclose the vessel. The jaws and the vessel share a tapered cam plate and roller system configured to bring the rings into vertically compressive locking engagement on the pressure vessel when the rings are moved into locking position. Mechanical interlocks provide security against back pressure opening the rings.
    Type: Grant
    Filed: February 13, 1998
    Date of Patent: May 30, 2000
    Assignee: G.T. Equipment Technologies, Inc.
    Inventors: Robert B. Farmer, Bernard D. Jones, Kedar P. Gupta, Ijaz H. Jafri, Derek M. Dispensa
  • Patent number: 6019841
    Abstract: The invention is an improved method and apparatus for growing crystals that incorporates an isolation valve between the growth and injection chambers to allow the growth chamber to be maintained at operating temperature and pressure while decoupling the injector chamber in order to make changes necessary to restart or advance the process. Separate heating elements in the injector assembly or chamber provide related heating control. Upper and lower load cells and programmable signal amplifiers are configured to weigh and output the dynamic weight range of the loss or gain of process materials of the growth chamber crucible and the injector assembly, and are connected by electrical slip rings or wireless means to a computer control system.
    Type: Grant
    Filed: March 24, 1998
    Date of Patent: February 1, 2000
    Assignee: G.T. Equuipment Technologies Inc.
    Inventors: Ijaz H. Jafri, Mohan Chandra, Rick C. White, Kedar P. Gupta, Robert B. Farmer, Bernard D. Jones, David F. Bliss
  • Patent number: 5242667
    Abstract: The present invention is directed toward a feeder system for replenishing the melt in a crystal growing system that utilizes a heated crucible containing a pool of melted charge material from which a seen is withdrawn to grow the crystal. The feed system utilizes a storage hopper for storing solid pellets of the charge material. The storage hopper is provided with an opening at the bottom thereof which allows pellets to flow out of the hopper. A rotating plate is provided below the opening for collecting pellets that flow from the opening and enables piles of pellets to be formed thereon. A wiper is provided that extends across a portion of the plate and, as the plate is rotated, contacts the pellet piles to wipe pellets off of the plate. Thereafter, the pellets are collected and sourced to the melt to accomplish replenishment thereof.
    Type: Grant
    Filed: July 26, 1991
    Date of Patent: September 7, 1993
    Assignee: Ferrofluidics Corporation
    Inventors: Jurek K. Koziol, Jonathan A. Talbott, Kedar P. Gupta, George F. Lewis
  • Patent number: 4257841
    Abstract: Apparatus and method for stabilizing and supporting a crystal semiconductor rod during fabrication refining from the action of a seed rod on a float zone melt of a crystalline rod source is provided wherein engageable fingers mounted in a vertically movable tube in axial register with the shaft holding the crystal seed rod are pivotally mounted in a non-horizontal upward position, the finger tips being force loaded for inward movement upon removal of a sleeve carrier so that the fingers engage, support, and stabilize the irregular cylindrical surface of the refined semiconductor rod. The tube and fingers are engageable through sleeve and tube piston means resulting in uniform stabilization and support of the crystal refined rod. The apparatus and method prevent the refined rod from vibrating and oscillating about its axis; thus allowing enlarged dislocation free crystal rod growth from a crystalline rod source, said refined crystal rod being grown on a slender seed rod.
    Type: Grant
    Filed: January 6, 1978
    Date of Patent: March 24, 1981
    Assignee: Monsanto Company
    Inventors: John M. Ross, Kedar P. Gupta, Horst G. Kramer, John W. Burd
  • Patent number: 4201746
    Abstract: Improvements in apparatus for zone refining polycrystalline semiconductor rods to produce monocrystalline semiconductor rods are disclosed. In the apparatus, an inductive heating chamber is employed which has a longitudinal dimension independent of the length of the polycrystalline semiconductor rod to be processed. The longitudinal dimension of the induction heating chamber is limited only by considerations of the space required for the RF induction heating coil and related apparatus which must be mounted within the chamber, the viewing space required for the operator to observe the zone refining process, and the heating effect on the structures above and below the chamber. First and second gas tight bellows are provided which, respectively, surround the rod holder and the seed holder.
    Type: Grant
    Filed: June 13, 1977
    Date of Patent: May 6, 1980
    Assignee: Monsanto Company
    Inventors: John W. Burd, Bobbie D. Stone, William F. Tucker, Kedar P. Gupta
  • Patent number: 4184135
    Abstract: A breakapart single turn RF induction coil suitable for use in zone refining production of large diameter semiconductor rods is described wherein the coil is engagable and disengagable from mounted semiconductor rods without breaking the rod or mounting welds. The work coil consists of two spaced apart sections; however connected at one or both ends of a slit formed between the two sections with current and coolant flow through the connection means on the outer peripheral of the sections. The arrangement affords the use of a single turn coil having the capacity for removal from a float zone without disruption of the semiconductor rod mounting.
    Type: Grant
    Filed: April 10, 1978
    Date of Patent: January 15, 1980
    Assignee: Monsanto Company
    Inventors: Kedar P. Gupta, J. W. Thousand, Jr.
  • Patent number: 4045181
    Abstract: Improvements in apparatus for zone refining polycrystalline semiconductor rods to produce monocrystalline semiconductor rods are disclosed. In the apparatus, an inductive heating chamber is employed which has a longitudinal dimension independent of the length of the polycrystalline semiconductor rod to be processed. The longitudinal dimension of the induction heating chamber is limited only by considerations of the space required for the RF induction heating coil and related apparatus which must be mounted within the chamber, the viewing space required for the operator to observe the zone refining process, and the heating effect on the structures above and below the chamber. First and second gas tight bellows are provided which, respectively, surround the rod holder and the seed holder.
    Type: Grant
    Filed: December 27, 1976
    Date of Patent: August 30, 1977
    Assignee: Monsanto Company
    Inventors: John W. Burd, Bobbie D. Stone, William F. Tucker, Kedar P. Gupta