Patents by Inventor Umesh Kumar

Umesh Kumar 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: 5795798
    Abstract: A method and apparatus for producing full-color luminescent monolithic semiconductor devices. Each portion of the device is bandgap engineered by using different dopants to change the direct bandgap of selected areas of each region, thereby allowing that region to produce different wavelengths of emitted light at high efficiencies.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: August 18, 1998
    Assignee: The Regents of the University of California
    Inventors: Umesh Kumar Mishra, Steven P. DenBaars, David Joseph Kapolnek
  • Patent number: 5780355
    Abstract: A method for producing Group III nitride films with high indium content and superior optical quality. The Group III nitride film will produce light in the ultraviolet, blue, green, yellow, and red spectral regions. This will enable fabrication of full-color displays and produce a reliable white light source. A metal organic chemical vapor deposition (MOCVD) process in combination with a photochemical process reduces the growth temperature required to produce optical quality Group III nitride films.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: July 14, 1998
    Assignee: The Regents of the University of California
    Inventors: Umesh Kumar Mishra, Steven P. DenBaars, Stacia Keller
  • Patent number: 5780922
    Abstract: A germanium-based field effect transistor has a passivation layer of aluminum oxide below a germanium channel and aluminum oxide gate oxide layer formed over the channel. The aluminum oxide layers are treated to reduce the density of surface state impurities, particularly arsenic released in the oxide layer as a result of forming the oxide layer. The low surface state germanium channel has very low phase noise and is suitable for use as a local oscillator in a heterodyne receiver.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: July 14, 1998
    Assignee: The Regents of the University of California
    Inventors: Umesh Kumar Mishra, Steven P. DenBaars
  • Patent number: 5759432
    Abstract: A relaxor ferroelectric composition that has the components lead magnesium niobate, lead titanate, and lead magnesium tungstate. The components are preferably present in relative molar amounts of (1-x-y) lead magnesium niobate, (x) lead titanate, and (y) lead magnesium tungstate, where 0.11.ltoreq.x.ltoreq.0.13 and 0.01.ltoreq.y.ltoreq.0.03. Also disclosed is a tunable ultrasonic transducer made of a relaxor ferroelectric composition that has the components lead magnesium niobate, lead titanate, and lead magnesium tunstate. A method of making a relaxor ferroelectric material comprising the step of adding an effective amount of lead magnesium tungstate to a lead magnesium niobate-lead titanate composition is also disclosed.
    Type: Grant
    Filed: June 14, 1996
    Date of Patent: June 2, 1998
    Assignee: Penn State Research Foundation
    Inventors: Umesh Kumar, Wayne Huebner, Sea Fue Wang
  • Patent number: 5747838
    Abstract: A gallium arsenide-based field effect transistor has a passivation layer of aluminum oxide below a gallium arsenide channel and aluminum oxide gate oxide layer formed over the channel. The aluminum oxide layers are treated to reduce the density of surface state impurities, particularly arsenic released in the oxide layer as a result of forming the oxide layer. The low surface state gallium arsenide channel has very low phase noise and is suitable for use as a local oscillator in a heterodyne receiver.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: May 5, 1998
    Assignee: The Regents of the University of California
    Inventors: Umesh Kumar Mishra, Steven P. DenBaars