Patents by Inventor Robert S. Sposili

Robert S. Sposili 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: 8859436
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed. In one preferred arrangement, a method includes the steps of generating a sequence of excimer laser pulses, controllably modulating each excimer laser pulse in the sequence to a predetermined fluence, masking portions of each fluence controlled laser pulse in the sequence with a two dimensional pattern of slits to generate a sequence of fluence controlled pulses of line patterned beamlets, irradiating an amorphous silicon thin film sample with the sequence of fluence controlled slit patterned beamlets to effect melting of portions thereof, and controllably sequentially translating a relative position of the sample with respect to each of the fluence controlled pulse of slit patterned beamlets to thereby process the amorphous silicon thin film sample into a single or polycrystalline silicon thin film.
    Type: Grant
    Filed: March 11, 2009
    Date of Patent: October 14, 2014
    Assignee: The Trustees of Columbia University in the City of New York
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Patent number: 8680427
    Abstract: A device on a supporting substrate is provided including a semiconductor film, having two or more rectangular crystalline regions spaced from each other, wherein each of the two or more rectangular crystalline regions comprises one single crystal region. The device can further include two or more thin-film transistors, wherein each of the two or more thin-film transistors comprises one or more active-channel regions. Each of the one or more active-channel regions can comprise at least one of said two or more rectangular crystalline regions. The device can further include an integrated circuit which comprises of the two or more thin-film transistors.
    Type: Grant
    Filed: April 7, 2009
    Date of Patent: March 25, 2014
    Assignee: The Trustees Of Columbia University in The City Of New York
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Publication number: 20130009074
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed. One method includes generating a sequence of excimer laser pulses, controllably modulating each pulse to a predetermined fluence, homoginizing each modulated pulse in a predetermined plane, masking portions of each homoginized pulse with a pattern of slits to generate a sequence of fluence controlled pulses of line patterned beamlets, each slit in the pattern of slits being sufficiently narrow to prevent inducement of significant nucleation in region of a silicon thin film sample irradiated by a beamlet corresponding to the slit, irradiating an amorphous silicon thin film sample with the sequence of fluence controlled slit patterned beamlets to effect melting of portions corresponding to each fluence controlled patterned beamlet pulse, and controllably sequentially translating a relative position of the sample with respect to each of the fluence controlled pulse of slit patterned beamlets.
    Type: Application
    Filed: August 28, 2012
    Publication date: January 10, 2013
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Patent number: 8278659
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.
    Type: Grant
    Filed: September 25, 2009
    Date of Patent: October 2, 2012
    Assignee: The Trustees of Columbia University in the city of New York
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Publication number: 20110068342
    Abstract: A laser method is provided for minimizing variations in transistor threshold voltages. The method supplies a wafer with a laser-crystallized active semiconductor film having a top surface with a first surface roughness. The method laser anneals the active semiconductor film, and in response to the laser annealing, melts the top surface of the active semiconductor film. The result is a top surface with a second roughness, less than the first roughness. More explicitly, the wafer active semiconductor film is crystallized using a laser with a first fluence, and then laser annealed with a second fluence, less than the first fluence. As compared with complementary metal-oxide-semiconductor field-effect (CMOSFET) thin-film transistor (TFT) structures formed in unprocessed regions of the active semiconductor film, the TFT threshold voltage standard deviation for TFTs in laser annealed portions of the active film are 60% less for n-channel and 30% less for p-channel TFTs.
    Type: Application
    Filed: September 18, 2009
    Publication date: March 24, 2011
    Inventors: Themistokles Afentakis, Robert S. Sposili, Steven R. Droes
  • Publication number: 20100102323
    Abstract: A method is provided for forming a directionally crystallized (100)-normal crystallographic orientation silicon (Si) film. The method provides a substrate including Si. An amorphous Si (a-Si) layer is formed overlying the substrate, and a silicon oxide cap layer is formed overlying the a-Si layer. In response to scanning a laser in a first direction along a top surface of the silicon oxide cap layer, the a-Si layer is transformed into a crystalline Si film having a (100)-normal crystallographic orientation, with crystal grains elongated in the first direction. That is, the crystalline Si film has grain boundaries between crystal grains, aligned in parallel with the first direction.
    Type: Application
    Filed: October 24, 2008
    Publication date: April 29, 2010
    Inventors: Robert S. Sposili, Apostolos T. Voutsas
  • Patent number: 7704862
    Abstract: Systems and methods for reducing a surface roughness of a polycrystalline or single crystal thin film produced by the sequential lateral solidification process are disclosed.
    Type: Grant
    Filed: February 6, 2007
    Date of Patent: April 27, 2010
    Assignee: The Trustees of Columbia University
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Patent number: 7679028
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.
    Type: Grant
    Filed: May 4, 2007
    Date of Patent: March 16, 2010
    Assignee: The Trustees of Columbia University in the City of New York
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Publication number: 20100032586
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.
    Type: Application
    Filed: September 25, 2009
    Publication date: February 11, 2010
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Patent number: 7608144
    Abstract: A process of lateral crystallization is provided for increasing the lateral growth length (LGL). A localized region of the substrate is heated for a short period of time. While the localized region of the substrate is still heated, a silicon film overlying the substrate is irradiated to anneal the silicon film to crystallize a portion of the silicon film in thermal contact with the heated substrate region. A CO2 laser may be used as a heat source to heat the substrate, while a UV laser or a visible spectrum laser is used to irradiate and crystallize the film.
    Type: Grant
    Filed: October 31, 2005
    Date of Patent: October 27, 2009
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Apostolos T. Voutsas, Robert S. Sposili, Mark A. Crowder
  • Publication number: 20090250791
    Abstract: Crystalline semiconductor stripes and an associated fabrication process are provided. The method provides an insulator substrate, and deposits a semiconductor layer overlying the insulator substrate. The semiconductor layer is irradiated using a scanning step-and-repeat laser annealing process, which agglomerates portions of the semiconductor layer. In response to cooling agglomerated semiconductor material, oriented crystalline semiconductor stripes are formed on the insulator substrate. The crystalline semiconductor stripes are aligned approximately with a straight line stripe axis overlying a top surface of the insulating substrate. Each crystalline semiconductor stripe includes a plurality of consecutive ring segments aligned with the stripe axis. The rings segments have a width about equal to the laser annealing process step distance. The crystalline semiconductor stripes typically have a top surface shape of a truncated cylinder or a parabolic cross section.
    Type: Application
    Filed: April 8, 2008
    Publication date: October 8, 2009
    Inventors: Themistokles Afentakis, Robert S. Sposili, Apostolos T. Voutsas
  • Publication number: 20090250700
    Abstract: A transistor with crystalline semiconductor stripes and an associated fabrication process are provided. The method provides a substrate, and deposits a semiconductor layer overlying the substrate. The semiconductor layer is irradiated using a scanning step-and-repeat laser annealing process, which agglomerates portions of the semiconductor layer. In response to cooling agglomerated semiconductor material, a transistor active semiconductor region is formed including a plurality of crystalline semiconductor stripes oriented along parallel axes. In one aspect, a channel region is formed from the plurality of oriented crystalline semiconductor stripes, and the method forms a gate dielectric overlying the channel region, with a gate electrode overlying the gate dielectric. In another aspect, forming the transistor active semiconductor region includes forming source, drain, and channel regions from the plurality of oriented crystalline semiconductor stripes.
    Type: Application
    Filed: April 8, 2008
    Publication date: October 8, 2009
    Inventors: Themistokles Afentakis, Robert S. Sposili, Apostolos T. Voutsas
  • Publication number: 20090189164
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.
    Type: Application
    Filed: April 7, 2009
    Publication date: July 30, 2009
    Inventors: JAMES S. IM, Robert S. Sposili, Mark A. Crowder
  • Publication number: 20090173948
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.
    Type: Application
    Filed: March 11, 2009
    Publication date: July 9, 2009
    Inventors: JAMES S. IM, ROBERT S. SPOSILI, MARK A. CROWDER
  • Publication number: 20090078940
    Abstract: A structure with location-controlled crystallization of an active semiconductor film using a crystal seed has been provided, along with an associated fabrication method. The method forms a first semiconductor film overlying a substrate having a crystallographic orientation. Typically, the structure is polycrystalline or single-crystal. The first semiconductor film is selectively etched, forming a seed region. An insulator is formed with an opening, exposing the seed region. An amorphous second semiconductor film is formed over the insulator layer. The second semiconductor film is laser annealed, partially melting the seed region. Crystal grains are laterally grown in the second semiconductor film having the same crystallographic orientation as the seed region. In TFT fabrication an etching is typically performed to remove the second semiconductor film overlying the seed region, and a transistor active region is formed in the remaining second semiconductor film.
    Type: Application
    Filed: September 26, 2007
    Publication date: March 26, 2009
    Inventors: Themistokles Afentakis, Robert S. Sposili, Apostolos T. Voutsas
  • Patent number: 7319056
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.
    Type: Grant
    Filed: June 1, 2005
    Date of Patent: January 15, 2008
    Assignee: The Trustees of Columbia University in the City of New York
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Patent number: 7220660
    Abstract: Systems and methods for reducing a surface roughness of a polycrystalline or single crystal thin film produced by the sequential lateral solidification process are disclosed.
    Type: Grant
    Filed: September 13, 2004
    Date of Patent: May 22, 2007
    Assignee: The Trustees of Columbia University in the City of New York
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Patent number: 7056843
    Abstract: A process of lateral crystallization comprises providing a silicon film on a substrate surface, exposing a localized substrate region at the substrate surface to a laser heating source, and annealing a portion of the silicon film in thermal contact with the localized substrate region by exposing the silicon film to a low-fluence optical annealing source.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: June 6, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Robert S. Sposili, Mark A. Crowder, Apostolos T. Voutsas
  • Patent number: 7029996
    Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.
    Type: Grant
    Filed: November 13, 2002
    Date of Patent: April 18, 2006
    Assignee: The Trustees of Columbia University in the City of New York
    Inventors: James S. Im, Robert S. Sposili, Mark A. Crowder
  • Patent number: 7018468
    Abstract: A process of lateral crystallization is provided for increasing the lateral growth length (LGL). A localized region of the substrate is heated for a short period of time. While the localized region of the substrate is still heated, a silicon film overlying the substrate is irradiated to anneal the silicon film to crystallize a portion of the silicon film in thermal contact with the heated substrate region. A CO2 laser may be used as a heat source to heat the substrate, while a UV laser or a visible spectrum laser is used to irradiate and crystallize the film.
    Type: Grant
    Filed: November 13, 2003
    Date of Patent: March 28, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Apostolos T. Voutsas, Robert S. Sposili, Mark A. Crowder