Patents by Inventor Michael P. Stewart

Michael P. Stewart 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: 8207005
    Abstract: Embodiments of the invention contemplate the formation of a high efficiency solar cell using novel methods to form the active doped region(s) and the metal contact structure of the solar cell device. In one embodiment, the methods include the steps of depositing a dielectric material that is used to define the boundaries of the active regions and/or contact structure of a solar cell device. Various techniques may be used to form the active regions of the solar cell and the metal contact structure.
    Type: Grant
    Filed: March 7, 2011
    Date of Patent: June 26, 2012
    Assignee: Applied Materials, Inc.
    Inventors: Timothy W. Weidman, Rohit Mishra, Michael P. Stewart, Kapila P. Wijekoon, Yonghwa Chris Cha, Tristan Holtam, Vinay Shah
  • Patent number: 8183081
    Abstract: Embodiments of the invention generally provide a high efficiency solar cell using a novel processing sequence to form a solar cell device. In one embodiment, the methods include forming one or more layers on a backside of a solar cell substrate prior to the texturing process to prevent attack of the backside surface of the substrate. In one embodiment, the one or more layers are a metalized backside contact structure that is formed on the backside of the solar cell substrate. In another embodiment, the one or more layers are a chemical resistant dielectric layer that is formed over the backside of the solar cell substrate.
    Type: Grant
    Filed: July 16, 2009
    Date of Patent: May 22, 2012
    Assignee: Applied Materials, Inc.
    Inventors: Timothy W. Weidman, Rohit Mishra, Michael P. Stewart, Yonghwa Chris Cha, Kapila P. Wijekoon, Hongbin Fang
  • Patent number: 8168462
    Abstract: Embodiments of the invention contemplate the formation of a high efficiency solar cell using a novel plasma oxidation process to form a passivation film stack on a surface of a solar cell substrate. In one embodiment, the methods include providing a substrate having a first type of doping atom on a back surface of the substrate and a second type of doping atom on a front surface of the substrate, plasma oxidizing the back surface of the substrate to form an oxidation layer thereon, and forming a silicon nitride layer on the oxidation layer.
    Type: Grant
    Filed: June 5, 2009
    Date of Patent: May 1, 2012
    Assignee: Applied Materials, Inc.
    Inventors: Peter Borden, Michael P. Stewart, Li Xu, Hemant P. Mungekar, Christopher S. Olsen
  • Patent number: 8158203
    Abstract: The present invention is directed toward methods of attaching or grafting carbon nanotubes (CNTs) to silicon surfaces. In some embodiments, such attaching or grafting occurs via functional groups on either or both of the CNTs and silicon surface. In some embodiments, the methods of the present invention include: (1) reacting a silicon surface with a functionalizing agent (such as oligo(phenylene ethynylene)) to form a functionalized silicon surface; (2) dispersing a quantity of CNTs in a solvent to form dispersed CNTs; and (3) reacting the functionalized silicon surface with the dispersed CNTs. The present invention is also directed to the novel compositions produced by such methods.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: April 17, 2012
    Assignee: William Marsh Rice University
    Inventors: James M. Tour, Bo Chen, Austen K. Flatt, Michael P. Stewart, Christopher A. Dyke, Francisco Maya
  • Patent number: 8129212
    Abstract: Methods for surface texturing a crystalline silicon substrate are provided. In one embodiment, the method includes providing a crystalline silicon substrate, wetting the substrate with an alkaline solution comprising a wetting agent, and forming a textured surface with a structure having a depth about 1 ?m to about 10 ?m on the substrate. In another embodiment, a method of performing a substrate texture process includes providing crystalline silicon substrate, pre-cleaning the substrate in a HF aqueous solution, wetting the substrate with a KOH aqueous solution comprising polyethylene glycol (PEG) compound, and forming a textured surface with a structure having a depth about 3 ?m to about 8 ?m on the substrate.
    Type: Grant
    Filed: March 23, 2009
    Date of Patent: March 6, 2012
    Assignee: Applied Materials, Inc.
    Inventors: Kapila Wijekoon, Rohit Mishra, Michael P Stewart, Timothy Weidman, Hari Ponnekanti, Tristan R. Holtam
  • Publication number: 20110287577
    Abstract: The present invention generally provides a method of forming a high efficiency solar cell device by preparing a surface and/or forming at least a part of a high quality passivation layer on a silicon containing substrate. Embodiments of the present invention may be especially useful for preparing a surface of a p-type doped region formed on a silicon substrate so that a high quality passivation layer can be formed thereon. In one embodiment, the methods include exposing a surface of the solar cell substrate to a plasma to clean and modify the physical, chemical and/or electrical characteristics of the surface.
    Type: Application
    Filed: August 2, 2011
    Publication date: November 24, 2011
    Applicant: Applied Materials, Inc.
    Inventors: Michael P. STEWART, Lisong Zhou, Jen Shu, Li (Sherry) Xu
  • Publication number: 20110272625
    Abstract: Methods for surface texturing a crystalline silicon substrate are provided. In one embodiment, the method includes providing a crystalline silicon substrate, wetting the substrate with an alkaline solution comprising a wetting agent, and forming a textured surface with a structure having a depth about 1 ?m to about 10 ?m on the substrate. In another embodiment, a method of performing a substrate texture process includes providing crystalline silicon substrate, pre-cleaning the substrate in a HF aqueous solution, wetting the substrate with a KOH aqueous solution comprising polyethylene glycol (PEG) compound, and forming a textured surface with a structure having a depth about 3 ?m to about 8 ?m on the substrate.
    Type: Application
    Filed: July 13, 2011
    Publication date: November 10, 2011
    Inventors: Kapila Wijekoon, Rohit Mishra, Michael P. Stewart, Timothy Weidman, Hari Ponnekanti, Tristan R. Holtam
  • Publication number: 20110272024
    Abstract: Embodiments of the invention include a solar cell and methods of forming a solar cell. Specifically, the methods may be used to form a passivation/anti-reflection layer having combined functional and optical gradient properties on a solar cell substrate. The methods may include flowing a first process gas mixture into a process volume within a processing chamber generating plasma in the processing chamber at a power density of greater than 0.65 W/cm2 depositing a silicon nitride-containing interface sub-layer on a solar cell substrate in the process volume, flowing a second process gas mixture into the process volume, and depositing a silicon nitride-containing bulk sub-layer on the silicon nitride-containing interface sub-layer.
    Type: Application
    Filed: March 30, 2011
    Publication date: November 10, 2011
    Applicant: APPLIED MATERIALS, INC.
    Inventors: Dongwon Choi, Michael P. Stewart, Li Xu, Hemant P. Mungekar, Sunhom Paak, Kenneth MacWilliams
  • Publication number: 20110272008
    Abstract: Embodiments of the invention generally provide methods for forming a multilayer rear surface passivation layer on a solar cell substrate. The method includes forming a silicon oxide sub-layer having a net charge density of less than or equal to 2.1×1011 Coulombs/cm2 on a rear surface of a p-type doped region formed in a substrate comprising semiconductor material, the rear surface opposite a light receiving surface of the substrate and forming a silicon nitride sub-layer on the silicon oxide sub-layer. Embodiments of the invention also include a solar cell device that may be manufactured according methods disclosed herein.
    Type: Application
    Filed: May 5, 2011
    Publication date: November 10, 2011
    Applicant: APPLIED MATERIALS, INC.
    Inventors: Hemant P. Mungekar, Mukul Agrawal, Michael P. Stewart, Timothy W. Weidman, Rohit Mishra, Sunhom Paak
  • Publication number: 20110240114
    Abstract: The present invention generally provides a method of forming a high quality passivation layer over a p-type doped region to form a high efficiency solar cell device. Embodiments of the present invention may be especially useful for preparing a surface of a boron doped region formed in a silicon substrate. In one embodiment, the methods include exposing a surface of the solar cell substrate to a plasma to clean and modify the physical, chemical and/or electrical characteristics of the surface and then deposit a charged dielectric layer and passivation layer thereon.
    Type: Application
    Filed: March 14, 2011
    Publication date: October 6, 2011
    Applicant: Applied Materials, Inc.
    Inventors: Michael P. Stewart, Mukul Agrawal, Rohit Mishra, Hemant P. Mungekar, Timothy Weidman
  • Patent number: 8008208
    Abstract: The present invention generally provides a method of forming a high efficiency solar cell device by preparing a surface and/or forming at least a part of a high quality passivation layer on a silicon containing substrate. Embodiments of the present invention may be especially useful for preparing a surface of a p-type doped region formed on a silicon substrate so that a high quality passivation layer can be formed thereon. In one embodiment, the methods include exposing a surface of the solar cell substrate to a plasma to clean and modify the physical, chemical and/or electrical characteristics of the surface.
    Type: Grant
    Filed: December 7, 2010
    Date of Patent: August 30, 2011
    Assignee: Applied Materials, Inc.
    Inventors: Michael P. Stewart, Lisong Zhou, Jen Shu, Li (Sherry) Xu
  • Publication number: 20110183458
    Abstract: Embodiments of the invention contemplate the formation of a high efficiency solar cell using novel methods to form the active doped region(s) and the metal contact structure of the solar cell device. In one embodiment, the methods include the steps of depositing a dielectric material that is used to define the boundaries of the active regions and/or contact structure of a solar cell device. Various techniques may be used to form the active regions of the solar cell and the metal contact structure.
    Type: Application
    Filed: March 7, 2011
    Publication date: July 28, 2011
    Inventors: Timothy W. WEIDMAN, Rohit Mishra, Michael P. Stewart, Kapila P. Wijekoon, Yonghwa Chris Cha, Tristan Holtam, Vinay Shah
  • Publication number: 20110136286
    Abstract: The present invention generally provides a method of forming a high efficiency solar cell device by preparing a surface and/or forming at least a part of a high quality passivation layer on a silicon containing substrate. Embodiments of the present invention may be especially useful for preparing a surface of a p-type doped region formed on a silicon substrate so that a high quality passivation layer can be formed thereon. In one embodiment, the methods include exposing a surface of the solar cell substrate to a plasma to clean and modify the physical, chemical and/or electrical characteristics of the surface.
    Type: Application
    Filed: December 7, 2010
    Publication date: June 9, 2011
    Applicant: Applied Materials, Inc.
    Inventors: Michael P. Stewart, Lisong Zhou, Jen Shu, Li (Sherry) Xu
  • Patent number: 7951637
    Abstract: Embodiments of the invention contemplate the formation of a high efficiency solar cell using novel methods to form the active doped region(s) and the metal contact structure of the solar cell device. In one embodiment, the methods include the steps of depositing a dielectric material that is used to define the boundaries of the active regions and/or contact structure of a solar cell device. Various techniques may be used to form the active regions of the solar cell and the metal contact structure.
    Type: Grant
    Filed: August 27, 2009
    Date of Patent: May 31, 2011
    Assignee: Applied Materials, Inc.
    Inventors: Timothy W. Weidman, Rohit Mishra, Michael P. Stewart, Kapila P. Wijekoon, Yonghwa Chris Cha, Tristan Holtam, Vinay Shah
  • Publication number: 20100311203
    Abstract: Embodiments of the invention contemplate the formation of a high efficiency solar cell using a novel plasma oxidation process to form a passivation film stack on a surface of a solar cell substrate. In one embodiment, the methods include providing a substrate having a first type of doping atom on a back surface of the substrate and a second type of doping atom on a front surface of the substrate, plasma oxidizing the back surface of the substrate to form an oxidation layer thereon, and forming a silicon nitride layer on the oxidation layer.
    Type: Application
    Filed: June 5, 2009
    Publication date: December 9, 2010
    Applicant: APPLIED MATERIALS, INC.
    Inventors: Peter Borden, Michael P. Stewart, Li Xu, Hemant P. Mungekar, Christopher S. Olsen
  • Patent number: 7838077
    Abstract: This invention is generally related to a method of making a molecule-surface interface comprising at least one surface comprising at least one material and at least one organic group wherein the organic group is adjoined to the surface and the method comprises contacting at least one organic group precursor with at least one surface wherein the organic group precursor is capable of reacting with the surface in a manner sufficient to adjoin the organic group and the surface.
    Type: Grant
    Filed: March 19, 2009
    Date of Patent: November 23, 2010
    Assignee: William Marsh Rice University
    Inventors: James M. Tour, Michael P. Stewart
  • Publication number: 20100261302
    Abstract: A method and apparatus for cleaning layers of solar cell substrates is disclosed. The substrate is exposed to a reactive gas that may comprise neutral radicals comprising nitrogen and fluorine, or that may comprise anhydrous HF and water, alcohol, or a mixture of water and alcohol. The reactive gas may further comprise a carrier gas. The reactive gas etches the solar cell substrate surface, removing oxygen and other impurities. When exposed to the neutral radicals, the substrate grows a thin film containing ammonium hexafluorosilicate, which is subsequently removed by heat treatment.
    Type: Application
    Filed: June 28, 2010
    Publication date: October 14, 2010
    Applicant: APPLIED MATERIALS, INC.
    Inventors: VIRENDRA V. S. RANA, Michael P. Stewart
  • Publication number: 20100252824
    Abstract: This invention is generally related to a method of making a molecule-surface interface comprising at least one surface comprising at least one material and at least one organic group wherein the organic group is adjoined to the surface and the method comprises contacting at least one organic group precursor with at least one surface wherein the organic group precursor is capable of reacting with the surface in a manner sufficient to adjoin the organic group and the surface. The present invention is directed to hybrid molecular electronic devices having a molecule-surface interface. Such hybrid molecular electronic devices may advantageously have either a top or bottom gate electrode for modifying a conductivity of the devices.
    Type: Application
    Filed: April 5, 2010
    Publication date: October 7, 2010
    Applicant: WILLIAM MARSH RICE UNIVERSITY
    Inventors: James M. Tour, Michael P. Stewart, Jianli He, Harrry F. Pang
  • Patent number: 7749917
    Abstract: A method and apparatus for cleaning layers of solar cell substrates is disclosed. The substrate is exposed to a reactive gas that may comprise neutral radicals comprising nitrogen and fluorine, or that may comprise anhydrous HF and water, alcohol, or a mixture of water and alcohol. The reactive gas may further comprise a carrier gas. The reactive gas etches the solar cell substrate surface, removing oxygen and other impurities. When exposed to the neutral radicals, the substrate grows a thin film containing ammonium hexafluorosilicate, which is subsequently removed by heat treatment.
    Type: Grant
    Filed: March 13, 2009
    Date of Patent: July 6, 2010
    Assignee: Applied Materials, Inc.
    Inventors: Virendra V S Rana, Michael P. Stewart
  • Publication number: 20100167461
    Abstract: A method and apparatus for cleaning layers of solar cell substrates is disclosed. The substrate is exposed to a reactive gas that may comprise neutral radicals comprising nitrogen and fluorine, or that may comprise anhydrous HF and water, alcohol, or a mixture of water and alcohol. The reactive gas may further comprise a carrier gas. The reactive gas etches the solar cell substrate surface, removing oxygen and other impurities. When exposed to the neutral radicals, the substrate grows a thin film containing ammonium hexafluorosilicate, which is subsequently removed by heat treatment.
    Type: Application
    Filed: March 13, 2009
    Publication date: July 1, 2010
    Applicant: APPLIED MATERIALS, INC.
    Inventors: Virendra V.S. Rana, Michael P. Stewart