Patents by Inventor Virendra V. S. Rana
Virendra V. S. Rana 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: 8569650Abstract: Embodiments of the present invention generally provide methods and apparatus for material removal using lasers in the fabrication of solar cells. In one embodiment, an apparatus is provided that removes portions of a dielectric layer deposited on a solar cell substrate according to a desired pattern. In certain embodiments, methods for removing a portion of a material via a laser without damaging the underlying substrate are provided. In one embodiment, the intensity profile of the beam is adjusted so that the difference between the maximum and minimum intensity within a spot formed on a substrate surface is reduced to an optimum range. In one example, the substrate is positioned such that the peak intensity at the center versus the periphery of the substrate is lowered. In one embodiment, the pulse energy is improved to provide thermal stress and physical lift-off of a desired portion of a dielectric layer.Type: GrantFiled: August 2, 2012Date of Patent: October 29, 2013Assignee: Applied Materials, Inc.Inventors: Zhenhua Zhang, Virendra V. S. Rana, Vinay K. Shah, Chris Eberspacher
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Patent number: 8372753Abstract: 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: June 28, 2010Date of Patent: February 12, 2013Assignee: Applied Materials, Inc.Inventors: Virendra V S Rana, Michael P. Stewart
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Publication number: 20120295440Abstract: Embodiments of the present invention generally provide methods and apparatus for material removal using lasers in the fabrication of solar cells. In one embodiment, an apparatus is provided that removes portions of a dielectric layer deposited on a solar cell substrate according to a desired pattern. In certain embodiments, methods for removing a portion of a material via a laser without damaging the underlying substrate are provided. In one embodiment, the intensity profile of the beam is adjusted so that the difference between the maximum and minimum intensity within a spot formed on a substrate surface is reduced to an optimum range. In one example, the substrate is positioned such that the peak intensity at the center versus the periphery of the substrate is lowered. In one embodiment, the pulse energy is improved to provide thermal stress and physical lift-off of a desired portion of a dielectric layer.Type: ApplicationFiled: August 2, 2012Publication date: November 22, 2012Applicant: Applied Materials, Inc.Inventors: ZHENHUA ZHANG, Virendra V.S. Rana, Vinay K. Shah, Chris Eberspacher
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Patent number: 8283199Abstract: Embodiments of the present invention generally provide methods for forming conductive structures on the surfaces of a solar cell. In one embodiment, conductive structures are formed on the front surface of a solar cell by depositing a sacrificial polymer layer, forming patterned lines in the sacrificial polymer via a fluid jet, depositing metal layers over the front surface of the solar cell, and performing lift off of the metal layers deposited over the sacrificial polymer by dissolving the sacrificial polymer with a water based solvent.Type: GrantFiled: November 24, 2009Date of Patent: October 9, 2012Assignee: Applied Materials, Inc.Inventors: Virendra V. S. Rana, Chris Eberspacher, Karl J. Armstrong, Nety M. Krishna
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Patent number: 8258426Abstract: Embodiments of the present invention generally provide methods and apparatus for material removal using lasers in the fabrication of solar cells. In one embodiment, an apparatus is provided that precisely removes portions of a dielectric layer deposited on a solar cell substrate according to a desired pattern and deposits a conductive layer over the patterned dielectric layer. In one embodiment, the apparatus also removes portions of the conductive layer in a desired pattern. In certain embodiments, methods for removing a portion of a material via a laser without damaging the underlying substrate are provided. In one embodiment, the intensity profile of the beam is adjusted so that the difference between the maximum and minimum intensity within a spot formed on a substrate surface is reduced to an optimum range. In one example, the substrate is positioned such that the peak intensity at the center versus the periphery of the substrate is lowered.Type: GrantFiled: August 21, 2009Date of Patent: September 4, 2012Assignee: Applied Materials, Inc.Inventors: Zhenhua Zhang, Virendra V. S. Rana, Vinay K. Shah, Chris Eberspacher
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Patent number: 8173473Abstract: An apparatus and method for processing the solar cell substrates is provided. In one embodiment, a laser firing chamber for processing solar cell substrates placed in a carrier, comprising a laser module located at a side of the carrier, the laser module being adapted to generate and direct multiple laser beams over an entire surface of a plurality of solar cell substrates, and a transport adapted to convey the carrier through an outputting region of the laser beams.Type: GrantFiled: September 27, 2010Date of Patent: May 8, 2012Assignee: Applied Materials, Inc.Inventors: Derek Aqui, Steven M. Zuniga, Venkateswaran Subbaraman, Kirk Liebscher, John Alexander, Zhenhua Zhang, Virendra V. S. Rana
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Patent number: 8088675Abstract: A method for obtaining a desired dopant profile of an emitter for a solar cell which includes depositing a first amorphous silicon layer having a first doping level over an upper surface of the crystalline silicon substrate, depositing a second amorphous silicon layer having a second doping level on the first amorphous silicon layer, and heating the crystalline silicon substrate and the first and second amorphous silicon layers to a temperature sufficient to cause solid phase epitaxial crystallization of the first and second amorphous silicon layers, such that the first and second amorphous silicon layers, after heating, have the same grain structure and crystal orientation as the underlying crystalline silicon substrate.Type: GrantFiled: September 18, 2009Date of Patent: January 3, 2012Assignee: Applied Materials, Inc.Inventors: Virendra V. S. Rana, Robert Z. Bachrach
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Publication number: 20110076847Abstract: An apparatus and method for processing the solar cell substrates is provided. In one embodiment, a laser firing chamber for processing solar cell substrates placed in a carrier, comprising a laser module located at a side of the carrier, the laser module being adapted to generate and direct multiple laser beams over an entire surface of a plurality of solar cell substrates, and a transport adapted to convey the carrier through an outputting region of the laser beams.Type: ApplicationFiled: September 27, 2010Publication date: March 31, 2011Applicant: APPLIED MATERIALS, INC.Inventors: Derek Aqui, Steven M. Zuniga, Venkateswaran Subbaraman, Kirk Liebscher, John Alexander, Zhenhua Zhang, Virendra V.S. Rana
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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: 20100240172Abstract: A method for obtaining a desired dopant profile of an emitter for a solar cell which includes depositing a first amorphous silicon layer having a first doping level over an upper surface of the crystalline silicon substrate, depositing a second amorphous silicon layer having a second doping level on the first amorphous silicon layer, and heating the crystalline silicon substrate and the first and second amorphous silicon layers to a temperature sufficient to cause solid phase epitaxial crystallization of the first and second amorphous silicon layers, such that the first and second amorphous silicon layers, after heating, have the same grain structure and crystal orientation as the underlying crystalline silicon substrateType: ApplicationFiled: September 18, 2009Publication date: September 23, 2010Applicant: APPLIED MATERIALS, INC.Inventors: Virendra V.S. Rana, Robert Z. Bachrach
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Publication number: 20100190290Abstract: Embodiments of the present invention generally provide methods for forming conductive structures on the surfaces of a solar cell. In one embodiment, conductive structures are formed on the front surface of a solar cell by depositing a sacrificial polymer layer, forming patterned lines in the sacrificial polymer via a fluid jet, depositing metal layers over the front surface of the solar cell, and performing lift off of the metal layers deposited over the sacrificial polymer by dissolving the sacrificial polymer with a water based solvent.Type: ApplicationFiled: November 24, 2009Publication date: July 29, 2010Applicant: APPLIED MATERIALS, INC.Inventors: Virendra V.S. Rana, Chris Eberspacher, Karl J. Armstrong, Nety M. Krishna
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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
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Publication number: 20100055901Abstract: Embodiments of the present invention generally provide methods and apparatus for material removal using lasers in the fabrication of solar cells. In one embodiment, an apparatus is provided that precisely removes portions of a dielectric layer deposited on a solar cell substrate according to a desired pattern and deposits a conductive layer over the patterned dielectric layer. In one embodiment, the apparatus also removes portions of the conductive layer in a desired pattern. In certain embodiments, methods for removing a portion of a material via a laser without damaging the underlying substrate are provided. In one embodiment, the intensity profile of the beam is adjusted so that the difference between the maximum and minimum intensity within a spot formed on a substrate surface is reduced to an optimum range. In one example, the substrate is positioned such that the peak intensity at the center versus the periphery of the substrate is lowered.Type: ApplicationFiled: August 21, 2009Publication date: March 4, 2010Applicant: APPLIED MATERIALS, INC.Inventors: Zhenhua Zhang, Virendra V.S. Rana, Vinay K. Shah, Chris Eberspacher
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Patent number: 6374770Abstract: A chemical vapor deposition system that includes a housing configured to form a processing chamber, a substrate holder configured to hold a substrate within the processing chamber, a gas distribution system configured to introduce gases into the processing chamber, a plasma generation system configured to form a plasma within the processing chamber, a processor operatively coupled to control the gas distribution system and the plasma generation system, and a computer-readable memory coupled to the processor that stores a computer-readable program which directs the operation of the chemical vapor deposition system.Type: GrantFiled: June 20, 2000Date of Patent: April 23, 2002Assignee: Applied Materials, Inc.Inventors: Peter W. Lee, Stuardo Robles, Anand Gupta, Virendra V. S. Rana, Amrita Verma
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Patent number: 6289843Abstract: A method and apparatus for depositing a layer having improved film quality at an interface. The method includes the steps of introducing an inert gas into a processing chamber and forming a plasma from the inert gas by applying RF power to the chamber at a selected rate of increase. After RF power has reached full power, a process gas including a reactant gas is introduced to deposit the layer. In a preferred embodiment, the reactant gas is tetraethoxysilane. In another preferred embodiment, the process gas further includes fluorine.Type: GrantFiled: August 21, 2000Date of Patent: September 18, 2001Assignee: Applied Materials, Inc.Inventors: Anand Gupta, Virendra V. S. Rana, Amrita Verma, Mohan K. Bhan, Sudhakar Subrahmanyam
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Patent number: 6291028Abstract: A method and apparatus for depositing a layer having improved film quality at an interface. The method includes the steps of introducing an inert gas into a processing chamber and forming a plasma from the inert gas by applying RF power to the chamber at a selected rate of increase. After RF power has reached full power, a process gas including a reactant gas is introduced to deposit the layer. In a preferred embodiment, the reactant gas is tetraethoxysilane. In another preferred embodiment, the process gas further includes fluorine.Type: GrantFiled: June 30, 2000Date of Patent: September 18, 2001Assignee: Applied Materials, Inc.Inventors: Anand Gupta, Virendra V. S. Rana, Amrita Verma, Mohan K. Bhan, Sudhakar Subrahmanyam
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Patent number: 6191026Abstract: A semiconductor manufacturing process with improved gap fill capabilities is provided by a three step process of FSG deposition/etchback/FSG deposition. A first layer of FSG is partially deposited over a metal layer. An argon sputter etchback step is then carried out to etch out excess deposition material. Finally, a second layer of FSG is deposited to complete the gap fill process.Type: GrantFiled: January 9, 1996Date of Patent: February 20, 2001Assignee: Applied Materials, Inc.Inventors: Virendra V. S. Rana, Andrew Conners, Anand Gupta, Xin Guo, Soonil Hong
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Patent number: 6190233Abstract: A method and an apparatus for depositing a dielectric layer to fill in a gap between adjacent metal lines. In preferred embodiments of the method, a first dielectric layer is deposited over the lines and subsequently etched using both chemical and physical etchback steps. After the etchback steps are completed, a second dielectric layer is deposited over the first dielectric layer to fill in the gap.Type: GrantFiled: February 19, 1998Date of Patent: February 20, 2001Assignee: Applied Materials, Inc.Inventors: Soonil Hong, Choon Kun Ryu, Michael P. Nault, Kaushal K. Singh, Anthony Lam, Virendra V. S. Rana, Andrew Conners
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Patent number: 6121163Abstract: A method and apparatus for depositing a layer having improved film quality at an interface. The method includes the steps of introducing an inert gas into a processing chamber and forming a plasma from the inert gas by applying RF power to the chamber at a selected rate of increase. After RF power has reached full power, a process gas including a reactant gas is introduced to deposit the layer. In a preferred embodiment, the reactant gas is tetraethoxysilane. In another preferred embodiment, the process gas further includes fluorine.Type: GrantFiled: February 9, 1996Date of Patent: September 19, 2000Assignee: Applied Materials, Inc.Inventors: Anand Gupta, Virendra V. S. Rana, Amrita Verma, Mohan K. Bhan, Sudhakar Subrahmanyam