Patents by Inventor Tangali S. Sudarshan

Tangali S. Sudarshan 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: 20110059003
    Abstract: A method of growing an epitaxial layer on a substrate is generally provided. According to the method, the substrate is heated in a chemical vapor deposition chamber to a growth temperature in the presence of a carbon source gas, then the epitaxial layer is grown on the substrate at the growth temperature, and finally the substrate is cooled in a chemical vapor deposition chamber to at least about 80% of the growth temperature in the presence of a carbon source gas. Substrates formed from this method can have a carrier lifetime between about 0.25 ?s and about 9.9 ?s.
    Type: Application
    Filed: September 7, 2010
    Publication date: March 10, 2011
    Applicant: UNIVERSITY OF SOUTH CAROLINA
    Inventors: Tangali S. Sudarshan, Amitesh Srivastava
  • Publication number: 20100289032
    Abstract: An electronic device includes a silicon carbide layer having a first conductivity type and a main junction adjacent a surface of the silicon carbide layer, and a junction termination region at the surface of the silicon carbide layer adjacent the main junction. Charge in the junction termination region decreases with lateral distance from the main junction, and a maximum charge in the junction termination region may be less than about 2×1014 cm?2.
    Type: Application
    Filed: March 8, 2010
    Publication date: November 18, 2010
    Inventors: Qingchun Zhang, Anant K. Agarwal, Tangali S. Sudarshan, Alexander Bolotnikov
  • Publication number: 20100276699
    Abstract: An optically-controlled power switch for use as an electrical switch is generally provided. The device can include a wide bandgap semiconducting material defining a stack having a p-n junction, a metal mask overlying the top surface of the stack and defining at least one opening to allow light to pass through the metal mask; a first lead wire connected to the metal stack; and a second lead wire connected to the bottom surface of the stack.
    Type: Application
    Filed: May 4, 2010
    Publication date: November 4, 2010
    Applicant: University of South Carolina
    Inventors: Feng Zhao, Tangali S. Sudarshan
  • Patent number: 7220978
    Abstract: A system and method for detecting defects in semiconductor wafers in a rapid non-destructive manner. Defects in semiconductor wafers can include micropipes and screw dislocations, stress striations, planer defects, polytype inclusions, and others. When a wafer is illuminated by polarized light, the defects induce birefringence of the polarized light that can be visualized by a polariscope to detect defects in wafers. Defects can cause linearly inputted polarized light to emerge as elliptically polarized light after transmission through a wafer having defects. Placing the wafer between a set of polarizers under the cross poles condition allows for a rapid non-destructive system and method for delineating and locating defects within a semiconductor wafer.
    Type: Grant
    Filed: April 15, 2003
    Date of Patent: May 22, 2007
    Assignee: The University of South Carolina
    Inventors: Xianyun Ma, Tangali S. Sudarshan
  • Patent number: 7061021
    Abstract: This invention is directed to a system and method of fabricating PN and PiN diodes by diffusing an acceptor impurity into a substrate. This invention is particularly advantageous for fabricating SiC diodes having linearly graded, deep pn junctions. One method that this invention uses to achieve its advantages is by diffusing an acceptor impurity into a substrate using a crucible, acceptor source, substrate, and furnace.
    Type: Grant
    Filed: May 3, 2004
    Date of Patent: June 13, 2006
    Assignee: The University of South Carolina
    Inventors: Tangali S. Sudarshan, Stanislav Soloviev, Ying Gao
  • Publication number: 20040206891
    Abstract: A system and method for detecting defects in semiconductor wafers in a rapid non-destructive manner. Defects in semiconductor wafers can include micropipes and screw dislocations, stress striations, planer defects, polytype inclusions, and others. When a wafer is illuminated by polarized light, the defects induce birefringence of the polarized light that can be visualized by a polariscope to detect defects in wafers. Defects can cause linearly inputted polarized light to emerge as elliptically polarized light after transmission through a wafer having defects. Placing the wafer between a set of polarizers under the cross poles condition allows for a rapid non-destructive system and method for delineating and locating defects within a semiconductor wafer.
    Type: Application
    Filed: April 15, 2003
    Publication date: October 21, 2004
    Inventors: Xianyun Ma, Tangali S. Sudarshan
  • Patent number: 4780176
    Abstract: A method of wetting and coating various metals, which have been mechanically polished and chemically cleaned and etched, includes plasma cleaning and etching the metal and delivering mercury or other liquid metals through the plasma to the surface of the metal to be wetted. Tungsten, molybdenum, steels and elkonite are among the metals which may be wetted with a liquid metal according to the method of this invention. Molybdenum is cleaned and etched in a solution of 2-propanol and H.sub.2 O.sub.2.
    Type: Grant
    Filed: June 30, 1983
    Date of Patent: October 25, 1988
    Assignee: University of South Carolina
    Inventors: Tangali S. Sudarshan, Larry Park, Meng H. Lim, James E. Thompson