Patents by Inventor Kalluri R. Sarma

Kalluri R. Sarma 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).

  • Patent number: 5110748
    Abstract: High mobility thin film transistors for fabricating integrated drivers for active matrix displays and a special method of fabrication for obtaining the thin film transistors having mobility sufficiently high enough as drivers operable in the several megahertz frequency range needed for driving high resolution active matrix displays.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: May 5, 1992
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 4590024
    Abstract: An improved process is disclosed for the deposition in a reactor vessel of silicon on the interior walls of the reactor vessel and for the subsequent separation of the silicon from those walls. The reactor vessel has a generally rectangular cross section and is formed of a refractory material from which the deposited silicon separates by thermal expansion shear separation during cool down of the vessel and the deposited silicon. To improve the output of the deposition system, a plurality of partitions are provided in the reactor vessel and integral with the reactor walls. These partitions act as additional deposition surfaces, increasing the number of silicon sheets deposited as well as increasing the efficiency of the chemical reaction.
    Type: Grant
    Filed: March 29, 1984
    Date of Patent: May 20, 1986
    Assignee: Solavolt International
    Inventors: Israel A. Lesk, M. John Rice, Jr., Kalluri R. Sarma
  • Patent number: 4555303
    Abstract: A process is disclosed for removing carbonaceous material from a surface in a high pressure oxygen plasma. A surface, such as a surface of a silicon ribbon, having a layer of carbonaceous material thereon is positioned in a high pressure plasma reaction volume. A high pressure rf plasma is generated in which the plasma includes reactive and ionic oxygen species. The reactive oxygen species are directed to and react with the layer of carbonaceous material to oxidize that material. The reaction products of the oxidation step include carbon dioxide and, possibly a non-oxidizing ash material which can easily be removed from the silicon surface.
    Type: Grant
    Filed: October 2, 1984
    Date of Patent: November 26, 1985
    Assignee: Motorola, Inc.
    Inventors: Ronald Legge, M. John Rice, Jr., Kalluri R. Sarma
  • Patent number: 4542004
    Abstract: An improved process is disclosed for the high pressure plasma hydrogenation of silicon tetrachloride. Hydrogen and silicon tetrachloride are reacted in the presence of a high pressure plasma and further in the presence of a boron catalyst to form trichlorosilane and dichlorosilane. By adding the boron catalyst the overall conversion efficiency is increased and the dichlorosilane content in the reaction effluent is increased.
    Type: Grant
    Filed: March 28, 1984
    Date of Patent: September 17, 1985
    Assignee: Solavolt International
    Inventors: Kalluri R. Sarma, Charles S. Chanley
  • Patent number: 4510015
    Abstract: A method is provided for semiconductor ribbon-to-ribbon conversion in a rigid edge mode. A combination carrier and mask is provided by which the ribbon is secured during the conversion process. The carrier holds the ribbon and simultaneously masks the edges of the ribbon from the heating effects of an impinging energy beam. The energy beam, such as a laser or electron beam, impinges on the ribbon and creates a molten zone which extends through the thickness of the ribbon. During the growth process, the molten zone is caused to move along the length of the ribbon. The mask prevents melting of the extreme edge portions of the ribbon and thus allows a rapid growth rate and a stable molten zone without sophisticated electronic equipment to gate the energy beam at the ribbon edges.
    Type: Grant
    Filed: June 23, 1983
    Date of Patent: April 9, 1985
    Assignee: Motorola, Inc.
    Inventors: Ralph J. Ellis, Richard W. Gurtler, Kalluri R. Sarma
  • Patent number: 4491604
    Abstract: A step-wise process is disclosed for the efficient deposition of silicon. The process begins by reacting trichlorosilane and hydrogen on a heated substrate to deposit silicon. Silicon deposition efficiency of this reaction is determined by measuring the silicon to chlorine ratio in the deposition reaction effluent. The silicon-bearing effluent from the deposition reaction includes trichlorosilane, dichlorosilane, and silicon tetrachloride. The silicon-bearing effluent is collected in a first accumulator. The deposition reaction is continued using the collected quantity of silicon-bearing effluent together with an additional quantity of trichlorosilane as an input to the continuing reaction. The additional quantity of trichlorosilane is determined to make up the amount of silicon deposited in the previous step.
    Type: Grant
    Filed: December 27, 1982
    Date of Patent: January 1, 1985
    Inventors: Israel A. Lesk, Kalluri R. Sarma
  • Patent number: 4427638
    Abstract: Apparatus is provided for semiconductor ribbon-to-ribbon conversion in a rigid edge mode. A combination carrier and mask is provided by which the ribbon is secured during the conversion process. The carrier holds the ribbon and simultaneously masks the edges of the ribbon from the heating effects of an impinging energy beam. The energy beam, such as a laser or electron beam, impinges on the ribbon and creates a molten zone which extends through the thickness of the ribbon. During the growth process, the molten zone is caused to move along the length of the ribbon. The mask prevents melting of the extreme edge portions of the ribbon and thus allows a rapid growth rate and a stable molten zone without sophisticated electronic equipment to gate the energy beam at the ribbon edges.
    Type: Grant
    Filed: September 14, 1981
    Date of Patent: January 24, 1984
    Assignee: Motorola, Inc.
    Inventors: Ralph J. Ellis, Richard W. Gurtler, Kalluri R. Sarma
  • Patent number: 4382099
    Abstract: A method is provided for predepositing dopant material on semiconductor substrates. The semiconductor substrates are positioned within a high pressure plasma reactor apparatus. A high pressure rf plasma is generated in the apparatus at a pressure of about one atmosphere or greater. Dopant materials such as B.sub.2 H.sub.6, PH.sub.3, or AsH.sub.3 are introduced to the plasma and form ionized species of the dopant. The plasma and the ionized species are directed to the surface of the semiconductor substrates whereon a uniform layer of the dopant is deposited.
    Type: Grant
    Filed: October 26, 1981
    Date of Patent: May 3, 1983
    Assignee: Motorola, Inc.
    Inventors: Ronald N. Legge, Kalluri R. Sarma
  • Patent number: 4343830
    Abstract: Method and apparatus for minimizing the deleterious effects of structural imperfections in polycrystalline silicon solar cells uses a high pressure plasma system. The high pressure plasma system is used to introduce atomic hydrogen into the polycrystalline silicon substrates or into polycrystalline silicon solar cells. The silicon can be subjected to the hydrogenation either before or after it has a junction. The high pressure plasma system includes a high pressure chamber having a first and a second auxiliary chamber coupled to the high pressure chamber.
    Type: Grant
    Filed: November 13, 1980
    Date of Patent: August 10, 1982
    Assignee: Motorola, Inc.
    Inventors: Kalluri R. Sarma, Ronald N. Legge
  • Patent number: 4321246
    Abstract: Polycrystalline silicon is produced by a high pressure plasma process. A silicon halide or halosilane is reacted with hydrogen in the presence of a high pressure plasma to deposit silicon on a heated substrate. The effluent from this reaction is collected, the silicon-bearing compounds separated out, and re-introduced to the deposition reaction. The initial silicon bearing compound can be inexpensive silicon tetrachloride. Maximum utilization of all silicon bearing reaction products maximizes polycrystalline silicon production efficiency.
    Type: Grant
    Filed: May 9, 1980
    Date of Patent: March 23, 1982
    Assignee: Motorola, Inc.
    Inventors: Kalluri R. Sarma, M. John Rice, Jr., I. Arnold Lesk, Roger G. Nikirk
  • Patent number: 4309259
    Abstract: A method is disclosed for the plasma hydrogenation of silicon tetrachloride. A high pressure plasma is utilized to effect a reaction of hydrogen and silicon tetrachloride to form trichlorosilane and other hydrogenated silicon chlorides.
    Type: Grant
    Filed: May 9, 1980
    Date of Patent: January 5, 1982
    Assignee: Motorola, Inc.
    Inventors: Kalluri R. Sarma, M. John Rice, Jr.
  • Patent number: 4292342
    Abstract: Polycrystalline silicon is deposited on the interior surface of a shaped container. The silicon is deposited by reacting hydrogen and a silicon bearing gas in the presence of a high pressure plasma. The silicon body is separated from the shaped container by utilizing thermal expansion shear stress.
    Type: Grant
    Filed: May 9, 1980
    Date of Patent: September 29, 1981
    Assignee: Motorola, Inc.
    Inventors: Kalluri R. Sarma, M. John Rice, Jr., I. Arnold Lesk