Patents by Inventor Sarita Thakoor

Sarita Thakoor 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: 6108111
    Abstract: Photoresponse from a ferroelectric optical computing device, such as a memory cell or a logic switch, is increased by either illuminating the regions of the ferroelectric crystal under the electrode edges in a sandwich structure device or by aligning the principal axis of the ferroelectric crystal parallel to the linear polarization vector of the optical beam. Device density is increased by reducing the beam size using a small near-field optical fiber. Device evaluation including imprint failure susceptibility is performed by illuminating each ferroelectric optical computing device in a large array of such devices and storing the device address of any device whose response departs from a normal range.
    Type: Grant
    Filed: February 6, 1997
    Date of Patent: August 22, 2000
    Assignee: California Institute of Technology
    Inventors: Sarita Thakoor, Anilkumar P. Thakoor
  • Patent number: 5923182
    Abstract: Photoresponse from a ferroelectric optical computing device, such as a memory cell or a logic switch, is increased by either illuminating the regions of the ferroelectric crystal under the electrode edges in a sandwich structure device or by aligning the principal axis of the ferroelectric crystal parallel to the linear polarization vector of the optical beam. Device density is increased by reducing the beam size using a small near-field optical fiber. Device evaluation including imprint failure susceptibility is performed by illuminating each ferroelectric optical computing device in a large array of such devices and storing the device address of any device whose response departs from a normal range.
    Type: Grant
    Filed: May 23, 1996
    Date of Patent: July 13, 1999
    Assignee: California Institute of Technology
    Inventors: Sarita Thakoor, Anilkumar P. Thakoor
  • Patent number: 5621559
    Abstract: Photoresponse from a ferroelectric optical computing device, such as a memory cell or a logic switch, is increased by either illuminating the regions of the ferroelectric crystal under the electrode edges in a sandwich structure device or by aligning the principal axis of the ferroelectric crystal parallel to the linear polarization vector of the optical beam. Device density is increased by reducing the beam size using a small near-field optical fiber. Device evaluation including imprint failure susceptibility is performed by illuminating each ferroelectric optical computing device in a large array of such devices and storing the device address of any device whose response departs from a normal range.
    Type: Grant
    Filed: April 18, 1994
    Date of Patent: April 15, 1997
    Assignee: California Institute of Technology
    Inventors: Sarita Thakoor, Anilkumar P. Thakoor
  • Patent number: 5372859
    Abstract: Thin film ferroelectric capacitors (10) comprising a ferroelectric film (18) sandwiched between electrodes (16 and 20) for nonvolatile memory operations are rendered more stable by subjecting the capacitors to an anneal following deposition of the top electrode (20). The anneal is done so as to form the interface (22) between the ferroelectric film and the top electrode. Heating in an air oven, laser annealing, or electron bombardment may be used to form the interface. Heating in an air oven is done at a temperature at least equal to the crystallization temperature of the ferroelectric film. Where the ferroelectric film comprises lead zirconate titanate, annealing is done at about 550.degree. to 600.degree. C. for about 10 to 15 minutes. The formation treatment reduces the magnitude of charge associated with the non-switching pulse in the thin film ferroelectric capacitors. Reduction of this charge leads to significantly more stable nonvolatile memory operations in both digital and analog memory devices.
    Type: Grant
    Filed: October 20, 1992
    Date of Patent: December 13, 1994
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Sarita Thakoor
  • Patent number: 5206829
    Abstract: An electrically programmable, optically readable data or memory cell is configured from a thin film of ferroelectric material, such as PZT, sandwiched between a transparent top electrode and a bottom electrode. The output photoresponse, which may be a photocurrent or photo-emf, is a function of the product of the remanent polarization from a previously applied polarization voltage and the incident light intensity. The cell is useful for analog and digital data storage as well as opto-electric computing. The optical read operation is non-destructive of the remanent polarization. The cell provides a method for computing the product of stored data and incident optical data by applying an electrical signal to store data by polarizing the thin film ferroelectric material, and then applying an intensity modulated optical signal incident onto the thin film material to generate a photoresponse therein related to the product of the electrical and optical signals.
    Type: Grant
    Filed: October 24, 1990
    Date of Patent: April 27, 1993
    Inventors: Sarita Thakoor, Anilkumar P. Thakoor
  • Patent number: 5196101
    Abstract: Composite films of multicomponent materials, such as oxides and nitrides, e.g., lead zirconate titanate, are deposited by dc magnetron sputtering, employing a rotating substrate holder, which rotates relative to a plurality of targets, one target for each metal element of the multicomponent material. The sputtering is carried out in a reactive atmosphere. The substrates on which the layers are deposited are at ambient temperature. Following deposition of the composite film, the film is heated to a temperature sufficient to initiate a solid state reaction and form the final product, which is substantially single phase and substantially homogeneous.
    Type: Grant
    Filed: February 5, 1991
    Date of Patent: March 23, 1993
    Assignee: Califoria Institute of Technology
    Inventor: Sarita Thakoor
  • Patent number: 4839700
    Abstract: A solid-state variable resistance device (10) whose resistance can be repeatedly altered by a control signal over a wide range, and which will remain stable after the signal is removed, is formed on an insulated layer (14), supported on a substrate (12) and comprises a set of electrodes (16a, 16b) connected by a layer (18) of material, which changes from an insulator to a conductor upon the injection of ions, covered by a layer (22) of material with insulating properties which permit the passage of ions, overlaid by an ion donor material (20). The ion donor material is overlaid by an insulating layer (24) upon which is deposited a control gate (26) located above the contacts. In a preferred embodiment, the variable resistance material comprises WO.sub.3, the ion donor layer comprises Cr.sub.2 O.sub.3, and the layers sandwiching the ion donor layer comprise silicon monoxide.
    Type: Grant
    Filed: December 16, 1987
    Date of Patent: June 13, 1989
    Assignee: California Institute of Technology
    Inventors: Rajeshuni Ramesham, Sarita Thakoor, Taher Daud, Aniklumar P. Thakoor
  • Patent number: 4726890
    Abstract: Thin films of niobium nitride with high superconducting temperature (T.sub.c) of 15.7.degree. K. are deposited on substrates held at room temperature (.about.90.degree. C.) by heat sink throughout the sputtering process. Films deposited at P.sub.Ar >12.9.+-.0.2 mTorr exhibit higher T.sub.c with increasing P.sub.N2,I, with the highest T.sub.c achieved at P.sub.N2,I =3.7.+-.0.2 mTorr and total sputtering pressure P.sub.tot =16.6.+-.0.4. Further increase of N.sub.2 injection starts decreasing T.sub.c.
    Type: Grant
    Filed: August 12, 1985
    Date of Patent: February 23, 1988
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Sarita Thakoor, James L. Lamb, Anilkumar P. Thakoor, Satish K. Khanna