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).
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Patent number: 8207005Abstract: 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: GrantFiled: March 7, 2011Date of Patent: June 26, 2012Assignee: Applied Materials, Inc.Inventors: Timothy W. Weidman, Rohit Mishra, Michael P. Stewart, Kapila P. Wijekoon, Yonghwa Chris Cha, Tristan Holtam, Vinay Shah
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Patent number: 8183081Abstract: 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: GrantFiled: July 16, 2009Date of Patent: May 22, 2012Assignee: Applied Materials, Inc.Inventors: Timothy W. Weidman, Rohit Mishra, Michael P. Stewart, Yonghwa Chris Cha, Kapila P. Wijekoon, Hongbin Fang
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Patent number: 8168462Abstract: 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: GrantFiled: June 5, 2009Date of Patent: May 1, 2012Assignee: Applied Materials, Inc.Inventors: Peter Borden, Michael P. Stewart, Li Xu, Hemant P. Mungekar, Christopher S. Olsen
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Patent number: 8158203Abstract: 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: GrantFiled: May 6, 2005Date of Patent: April 17, 2012Assignee: William Marsh Rice UniversityInventors: James M. Tour, Bo Chen, Austen K. Flatt, Michael P. Stewart, Christopher A. Dyke, Francisco Maya
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Patent number: 8129212Abstract: 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: GrantFiled: March 23, 2009Date of Patent: March 6, 2012Assignee: Applied Materials, Inc.Inventors: Kapila Wijekoon, Rohit Mishra, Michael P Stewart, Timothy Weidman, Hari Ponnekanti, Tristan R. Holtam
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Publication number: 20110287577Abstract: 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: ApplicationFiled: August 2, 2011Publication date: November 24, 2011Applicant: Applied Materials, Inc.Inventors: Michael P. STEWART, Lisong Zhou, Jen Shu, Li (Sherry) Xu
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Publication number: 20110272625Abstract: 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: ApplicationFiled: July 13, 2011Publication date: November 10, 2011Inventors: Kapila Wijekoon, Rohit Mishra, Michael P. Stewart, Timothy Weidman, Hari Ponnekanti, Tristan R. Holtam
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Publication number: 20110272024Abstract: 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: ApplicationFiled: March 30, 2011Publication date: November 10, 2011Applicant: APPLIED MATERIALS, INC.Inventors: Dongwon Choi, Michael P. Stewart, Li Xu, Hemant P. Mungekar, Sunhom Paak, Kenneth MacWilliams
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Publication number: 20110272008Abstract: 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: ApplicationFiled: May 5, 2011Publication date: November 10, 2011Applicant: APPLIED MATERIALS, INC.Inventors: Hemant P. Mungekar, Mukul Agrawal, Michael P. Stewart, Timothy W. Weidman, Rohit Mishra, Sunhom Paak
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Publication number: 20110240114Abstract: 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: ApplicationFiled: March 14, 2011Publication date: October 6, 2011Applicant: Applied Materials, Inc.Inventors: Michael P. Stewart, Mukul Agrawal, Rohit Mishra, Hemant P. Mungekar, Timothy Weidman
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Patent number: 8008208Abstract: 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: GrantFiled: December 7, 2010Date of Patent: August 30, 2011Assignee: Applied Materials, Inc.Inventors: Michael P. Stewart, Lisong Zhou, Jen Shu, Li (Sherry) Xu
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Publication number: 20110183458Abstract: 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: ApplicationFiled: March 7, 2011Publication date: July 28, 2011Inventors: Timothy W. WEIDMAN, Rohit Mishra, Michael P. Stewart, Kapila P. Wijekoon, Yonghwa Chris Cha, Tristan Holtam, Vinay Shah
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Publication number: 20110136286Abstract: 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: ApplicationFiled: December 7, 2010Publication date: June 9, 2011Applicant: Applied Materials, Inc.Inventors: Michael P. Stewart, Lisong Zhou, Jen Shu, Li (Sherry) Xu
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Patent number: 7951637Abstract: 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: GrantFiled: August 27, 2009Date of Patent: May 31, 2011Assignee: Applied Materials, Inc.Inventors: Timothy W. Weidman, Rohit Mishra, Michael P. Stewart, Kapila P. Wijekoon, Yonghwa Chris Cha, Tristan Holtam, Vinay Shah
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Publication number: 20100311203Abstract: 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: ApplicationFiled: June 5, 2009Publication date: December 9, 2010Applicant: APPLIED MATERIALS, INC.Inventors: Peter Borden, Michael P. Stewart, Li Xu, Hemant P. Mungekar, Christopher S. Olsen
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Patent number: 7838077Abstract: 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: GrantFiled: March 19, 2009Date of Patent: November 23, 2010Assignee: William Marsh Rice UniversityInventors: James M. Tour, Michael P. Stewart
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Publication number: 20100261302Abstract: 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: ApplicationFiled: June 28, 2010Publication date: October 14, 2010Applicant: APPLIED MATERIALS, INC.Inventors: VIRENDRA V. S. RANA, Michael P. Stewart
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Publication number: 20100252824Abstract: 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: ApplicationFiled: April 5, 2010Publication date: October 7, 2010Applicant: WILLIAM MARSH RICE UNIVERSITYInventors: James M. Tour, Michael P. Stewart, Jianli He, Harrry F. Pang
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Patent number: 7749917Abstract: 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: GrantFiled: March 13, 2009Date of Patent: July 6, 2010Assignee: Applied Materials, Inc.Inventors: Virendra V S Rana, Michael P. Stewart
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Publication number: 20100167461Abstract: 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: ApplicationFiled: March 13, 2009Publication date: July 1, 2010Applicant: APPLIED MATERIALS, INC.Inventors: Virendra V.S. Rana, Michael P. Stewart