Patents by Inventor Pooran Chandra Joshi

Pooran Chandra Joshi 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).

  • Publication number: 20080224205
    Abstract: A method is provided for forming a low-temperature vertical gate insulator in a vertical thin-film transistor (V-TFT) fabrication process. The method comprises: forming a gate, having vertical sidewalls and a top surface, overlying a substrate insulation layer; depositing a silicon oxide thin-film gate insulator overlying the gate; plasma oxidizing the gate insulator at a temperature of less than 400° C., using a high-density plasma source; forming a first source/drain region overlying the gate top surface; forming a second source/drain region overlying the substrate insulation layer, adjacent a first gate sidewall; and, forming a channel region overlying the first gate sidewall, in the gate insulator interposed between the first and second source/drain regions. When the silicon oxide thin-film gate insulator is deposited overlying the gate a Si oxide layer, a low temperature deposition process can be used, so that a step-coverage of greater than 65% can be obtained.
    Type: Application
    Filed: April 23, 2008
    Publication date: September 18, 2008
    Inventors: Pooran Chandra Joshi, Apostolos T. Voutsas, John W. Hartzell
  • Patent number: 7381595
    Abstract: A method is provided for forming a low-temperature vertical gate insulator in a vertical thin-film transistor (V-TFT) fabrication process. The method comprises: forming a gate, having vertical sidewalls and a top surface, overlying a substrate insulation layer; depositing a silicon oxide thin-film gate insulator overlying the gate; plasma oxidizing the gate insulator at a temperature of less than 400° C., using a high-density plasma source; forming a first source/drain region overlying the gate top surface; forming a second source/drain region overlying the substrate insulation layer, adjacent a first gate sidewall; and, forming a channel region overlying the first gate sidewall, in the gate insulator interposed between the first and second source/drain regions. When the silicon oxide thin-film gate insulator is deposited overlying the gate a Si oxide layer, a low temperature deposition process can be used, so that a step-coverage of greater than 65% can be obtained.
    Type: Grant
    Filed: May 26, 2005
    Date of Patent: June 3, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, Apostolos T. Voutsas, John W. Hartzell
  • Publication number: 20080102641
    Abstract: A method of fabricating a grayscale reticle includes preparing a quartz substrate; depositing a layer of silicon-rich oxide on the quartz substrate; depositing a layer of silicon nitride as an oxidation barrier layer on the silicon-rich oxide layer; depositing and patterning a layer of photoresist; etching the silicon nitride layer with a pattern for the silicon nitride layer; removing the photoresist; cleaning the quartz substrate and the remaining layers; oxidizing the quartz substrate and the layers thereon, thereby converting the silicon-rich oxide layer to a transparent silicon dioxide layer; removing the remaining silicon nitride layer; forming the quartz substrate and the silicon dioxide thereon into a reticle; and using the reticle to pattern a microlens array.
    Type: Application
    Filed: October 27, 2006
    Publication date: May 1, 2008
    Inventors: Yoshi Ono, Bruce D. Ulrich, Pooran Chandra Joshi
  • Publication number: 20080084372
    Abstract: A pixel-by-pixel digitally-addressable, pixelated, fluid-assay, active-matrix micro-structure including plural pixels formed preferably on a glass or plastic substrate, wherein each pixel, formed utilizing low-temperature TFT and Si technology, includes (a) at least one functionalized, digitally-addressable assay sensor including at least one functionalized, digitally-addressable assay site which has been affinity-functionalized to respond to a selected, specific fluid-assay material, and (b) disposed operatively adjacent that sensor and its associated assay site, digitally-addressable and energizable electromagnetic field-creating structure which is selectively energizable to create, in the vicinity of the sensor and its associated assay site, a selected, ambient, electromagnetic field environment which is structured to assist, selectively and optionally only, in the reading-out of an assay-result response from the assay sensor and assay site.
    Type: Application
    Filed: July 10, 2007
    Publication date: April 10, 2008
    Inventors: John W. Hartzell, Pooran Chandra Joshi, Paul J. Schuele
  • Publication number: 20080084363
    Abstract: A method of producing a precursor, active-matrix, fluid-assay micro-structure including the steps of (1) utilizing low-temperature TFT and Si technology, establishing preferably on a glass or plastic substrate a matrix array of non-functionalized pixels, and (2) preparing at least one of these pixels for individual, digitally-addressed (a) functionalization, and (b) reading out, ultimately, of completed assay results.
    Type: Application
    Filed: July 10, 2007
    Publication date: April 10, 2008
    Inventors: John W. Hartzell, Pooran Chandra Joshi, Paul J. Schuele
  • Publication number: 20080085559
    Abstract: A method of performing a fluid-material assay employing a device including at least one active pixel having a sensor with an assay site functionalized for selected fluid-assay material. The method includes exposing the pixel's sensor assay site to such material, and in conjunction with such exposing, and employing the active nature of the pixel, remotely requesting from the pixel's sensor assay site an assay-result output report. The method further includes, in relation to the employing step, creating, relative to the sensor's assay site in the at least one pixel, a predetermined, pixel-specific electromagnetic field environment.
    Type: Application
    Filed: July 31, 2007
    Publication date: April 10, 2008
    Inventors: John W. Hartzell, Pooran Chandra Joshi, Paul J. Schuele, Andrei Gindilis
  • Publication number: 20080085564
    Abstract: A digitally-addressable, pixelated, DNA fluid-assay, active-matrix micro-structure formed, utilizing low-temperature TFT and Si technology, on a substrate preferably made of glass or plastic, and including at least one pixel which is defined by (a) an addressable pixel site, (b) a sensor home structure disposed within that site for receiving and hosting a functionalized assay site possessing a DNA oligonucleotide probe, and (c) an addressable, pixel-site-specific, energy-field-producing functionalizer (preferably optical) operable to functionalize such a probe on the assay site. Each pixel may also include a pixel-integrated optical detector. Further disclosed are related methodology facets involving (1) the making of such a micro-structure (a) in a precursor form (without a functionalized probe), and thereafter (b) in a finalized/functionalized form (with such a probe), and (2) the ultimate use of a completed micro-structure in the performance of a DNA assay.
    Type: Application
    Filed: July 10, 2007
    Publication date: April 10, 2008
    Inventors: John W. Hartzell, Pooran Chandra Joshi, Paul J. Schuele
  • Publication number: 20080084373
    Abstract: A method for producing an active-matrix, fluid-assay micro-structure including, utilizing low-temperature TFT and Si technology, establishing preferably on a glass or plastic substrate a matrix array of digitally-addressable, assay-material-specific-functionalizable pixels, and employing pixel-specific digital addressing for selected, array-established pixels, individually functionalizing these pixels.
    Type: Application
    Filed: July 10, 2007
    Publication date: April 10, 2008
    Inventors: John W. Hartzell, Pooran Chandra Joshi, Paul J. Schuele
  • Publication number: 20080085214
    Abstract: A pixel-by-pixel, digitally-addressable, pixelated, precursor, fluid-assay, active-matrix micro-structure including plural pixels formed preferably on a glass or plastic substrate, wherein each pixel, formed utilizing low-temperature TFT and Si technology, includes (a) at least one non-functionalized, digitally-addressable assay sensor, and (b), disposed operatively adjacent this sensor, digitally-addressable and energizable electromagnetic field-creating structure which is selectively energizable to create, in the vicinity of the at least one assay sensor, an ambient electromagnetic field environment which is structured to assist in functionalizing, as a possession on said at least one assay sensor, at least one digitally-addressable assay site which will display an affinity for a selected fluid-assay material.
    Type: Application
    Filed: July 10, 2007
    Publication date: April 10, 2008
    Inventors: John W. Hartzell, Pooran Chandra Joshi, Paul J. Schuele
  • Publication number: 20080079663
    Abstract: A pixel-by-pixel, digitally-addressable, pixelated, precursor, fluid-assay, active-matrix micro-structure including plural pixels formed on a substrate, wherein each pixel includes (a) at least one non-functionalized, digitally-addressable assay sensor, and (b), disposed operatively adjacent this sensor, digitally-addressable and energizable electromagnetic field-creating structure which is selectively energizable to create, in the vicinity of the at least one assay sensor, an ambient electromagnetic field environment which is structured to assist in functionalizing, as a possession on said at least one assay sensor, at least one digitally-addressable assay site which will display an affinity for a selected fluid-assay material.
    Type: Application
    Filed: June 22, 2007
    Publication date: April 3, 2008
    Inventors: John W. Hartzell, Pooran Chandra Joshi, Paul J. Schuele
  • Patent number: 7259055
    Abstract: A method for forming a high-luminescence Si electroluminescence (EL) phosphor is provided, with an EL device made from the Si phosphor. The method comprises: depositing a silicon-rich oxide (SRO) film, with Si nanocrystals, having a refractive index in the range of 1.5 to 2.1, and a porosity in the range of 5 to 20%; and, post-annealing the SRO film in an oxygen atmosphere. DC-sputtering or PECVD processes can be used to deposit the SRO film. In one aspect the method further comprises: HF buffered oxide etching (BOE) the SRO film; and, re-oxidizing the SRO film, to form a SiO2 layer around the Si nanocrystals in the SRO film. In one aspect, the SRO film is re-oxidized by annealing in an oxygen atmosphere. In this manner, a layer of SiO2 is formed around the Si nanocrystals having a thickness in the range of 1 to 5 nanometers (nm).
    Type: Grant
    Filed: February 24, 2005
    Date of Patent: August 21, 2007
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Pooran Chandra Joshi, Wei Gao, Yoshi Ono, Sheng Teng Hsu
  • Patent number: 7196383
    Abstract: An oxide interface and a method for fabricating an oxide interface are provided. The method comprises forming a silicon layer and an oxide layer overlying the silicon layer. The oxide layer is formed at a temperature of less than 400° C. using an inductively coupled plasma source. In some aspects of the method, the oxide layer is more than 20 nanometers (nm) thick and has a refractive index between 1.45 and 1.47. In some aspects of the method, the oxide layer is formed by plasma oxidizing the silicon layer, producing plasma oxide at a rate of up to approximately 4.4 nm per minute (after one minute). In some aspects of the method, a high-density plasma enhanced chemical vapor deposition (HD-PECVD) process is used to form the oxide layer. In some aspects of the method, the silicon and oxide layers are incorporated into a thin film transistor.
    Type: Grant
    Filed: January 28, 2005
    Date of Patent: March 27, 2007
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, John W. Hartzell, Masahiro Adachi, Yoshi Ono
  • Patent number: 7186663
    Abstract: A method is provided for forming a Si and Si—Ge thin films. The method comprises: providing a low temperature substrate material of plastic or glass; supplying an atmosphere; performing a high-density (HD) plasma process, such as an HD PECVD process using an inductively coupled plasma (ICP) source; maintaining a substrate temperature of 400 degrees C., or less; and, forming a semiconductor layer overlying the substrate that is made from Si or Si-germanium. The HD PECVD process is capable of depositing Si at a rate of greater than 100 ? per minute. The substrate temperature can be as low as 50 degrees C. Microcrystalline Si, a-Si, or a polycrystalline Si layer can be formed over the substrate. Further, the deposited Si can be either intrinsic or doped. Typically, the supplied atmosphere includes Si and H. For example, an atmosphere can be supplied including SiH4 and H2, or comprising H2 and Silane with H2/Silane ratio in the range of 0–100.
    Type: Grant
    Filed: June 17, 2004
    Date of Patent: March 6, 2007
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, Apostolos T. Voutsas, John W. Hartzell
  • Patent number: 7122488
    Abstract: Methods are provided for forming silicon dioxide (SiO2) on a silicon carbide (SiC) substrate. The method comprises: providing a SiC substrate; supplying an atmosphere including oxygen; performing a high-density (HD) plasma-based process; and, forming a SiO2 layer overlying the SiC substrate. Typically, performing the HD plasma-based process includes connecting a top electrode to an inductively coupled HD plasma source. In one aspect, SiO2 is grown on the SiC substrate. Then, an HD plasma oxidation process is performed that creates a reactive oxygen species and breaks the Si—C bonds in the SiC substrate, to form free Si and C atoms in the SiC substrate. The free Si atoms in the SiC substrate are bonded to the HD plasma-generated reactive oxygen species, and the SiO2 layer is grown.
    Type: Grant
    Filed: March 29, 2004
    Date of Patent: October 17, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, Apostolos T. Voutsas, John W. Hartzell
  • Patent number: 7122487
    Abstract: A deposition oxide interface with improved oxygen bonding and a method for bonding oxygen in an oxide layer are provided. The method includes depositing an M oxide layer where M is a first element selected from a group including elements chemically defined as a solid and having an oxidation state in a range of +2 to +5, plasma oxidizing the M oxide layer at a temperature of less than 400° C. using a high density plasma source, and in response to plasma oxidizing the M oxide layer, improving M-oxygen bonding in the M oxide layer. The plasma oxidation process diffuses excited oxygen radicals into the oxide layer. The plasma oxidation is performed at specified parameters including temperature, power density, pressure, process gas composition, and process gas flow. In some aspects of the method, M is silicon, and the oxide interface is incorporated into a thin film transistor.
    Type: Grant
    Filed: March 15, 2004
    Date of Patent: October 17, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventor: Pooran Chandra Joshi
  • Patent number: 7087537
    Abstract: A method for fabricating a thin film oxide is provided. The method includes: forming a substrate; treating the substrate at temperatures equal to and less than 360° C. using a high density (HD) plasma source; and forming an M oxide layer overlying the substrate where M is an element selected from a group including elements chemically defined as a solid and having an oxidation state in a range of +2 to +5. In some aspects, the method uses an inductively coupled plasma (ICP) source. In some aspects the ICP source is used to plasma oxidize the substrate. In other aspects, HD plasma enhanced chemical vapor deposition is used to deposit the M oxide layer on the substrate. In some aspects of the method, M is silicon and a silicon layer and an oxide layer are incorporated into a TFT.
    Type: Grant
    Filed: March 15, 2004
    Date of Patent: August 8, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, Apostolos T. Voutsas
  • Patent number: 6902960
    Abstract: An oxide interface and a method for fabricating an oxide interface are provided. The method comprises forming a silicon layer and an oxide layer overlying the silicon layer. The oxide layer is formed at a temperature of less than 400° C. using an inductively coupled plasma source. In some aspects of the method, the oxide layer is more than 20 nanometers (nm) thick and has a refractive index between 1.45 and 1.47. In some aspects of the method, the oxide layer is formed by plasma oxidizing the silicon layer, producing plasma oxide at a rate of up to approximately 4.4 nm per minute (after one minute). In some aspects of the method, a high-density plasma enhanced chemical vapor deposition (HD-PECVD) process is used to form the oxide layer. In some aspects of the method, the silicon and oxide layers are incorporated into a thin film transistor.
    Type: Grant
    Filed: November 14, 2002
    Date of Patent: June 7, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, John W. Hartzell, Masahiro Adachi, Yoshi Ono
  • Publication number: 20040214365
    Abstract: A deposition oxide interface with improved oxygen bonding and a method for bonding oxygen in an oxide layer are provided. The method includes depositing an M oxide layer where M is a first element selected from a group including elements chemically defined as a solid and having an oxidation state in a range of +2 to +5, plasma oxidizing the M oxide layer at a temperature of less than 400° C. using a high density plasma source, and in response to plasma oxidizing the M oxide layer, improving M-oxygen bonding in the M oxide layer. The plasma oxidation process diffuses excited oxygen radicals into the oxide layer. The plasma oxidation is performed at specified parameters including temperature, power density, pressure, process gas composition, and process gas flow. In some aspects of the method, M is silicon, and the oxide interface is incorporated into a thin film transistor.
    Type: Application
    Filed: March 15, 2004
    Publication date: October 28, 2004
    Applicant: Sharp Laboratories of America, Inc.
    Inventor: Pooran Chandra Joshi
  • Publication number: 20040094808
    Abstract: An oxide interface and a method for fabricating an oxide interface are provided. The method comprises forming a silicon layer and an oxide layer overlying the silicon layer. The oxide layer is formed at a temperature of less than 400° C. using an inductively coupled plasma source. In some aspects of the method, the oxide layer is more than 20 nanometers (nm) thick and has a refractive index between 1.45 and 1.47. In some aspects of the method, the oxide layer is formed by plasma oxidizing the silicon layer, producing plasma oxide at a rate of up to approximately 4.4 nm per minute (after one minute). In some aspects of the method, a high-density plasma enhanced chemical vapor deposition (HD-PECVD) process is used to form the oxide layer. In some aspects of the method, the silicon and oxide layers are incorporated into a thin film transistor.
    Type: Application
    Filed: November 14, 2002
    Publication date: May 20, 2004
    Applicant: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, John W. Hartzell, Masahiro Adachi, Yoshi Ono
  • Patent number: 6689646
    Abstract: A method is provided for fabricating a thin film oxide. The method include forming a first silicon layer, applying a second silicon layer overlying the first silicon layer, oxidizing the second silicon layer at a temperature of less than 400° C. using an inductively coupled plasma source, and forming a thin film oxide layer overlying the first silicon layer. In some cases, the thin film oxide layer overlies the oxidized second silicon layer and is formed by a high-density plasma enhanced chemical vapor deposition process and an inductively coupled plasma source at a temperature of less than 400° C. In some cases, the thin film oxide layer and the first silicon layer are incorporated into a thin film transistor and the thin film oxide layer has a fixed oxide charge density of 3×1011 per square centimeter.
    Type: Grant
    Filed: November 14, 2002
    Date of Patent: February 10, 2004
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Pooran Chandra Joshi, John W. Hartzell, Masahiro Adachi, Yoshi Ono