Patents by Inventor Mrinal Kanti Das

Mrinal Kanti Das 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: 6767843
    Abstract: Methods for fabricating a layer of oxide on a silicon carbide layer are provided by forming the oxide layer on the silicon carbide layer by oxidizing the silicon carbide layer in an N2O environment. A predetermined temperature profile and/or a predetermined flow rate profile of N2O are provided during the oxidation. The predetermined temperature profile and/or predetermined flow rate profile may be constant or variable and may include ramps to steady state conditions. The predetermined temperature profile and/or the predetermined flow rate profile are selected so as to reduce interface states of the oxide/silicon carbide interface with energies near the conduction band of SiC.
    Type: Grant
    Filed: October 1, 2001
    Date of Patent: July 27, 2004
    Assignee: Cree, Inc.
    Inventors: Lori A. Lipkin, Mrinal Kanti Das, John W. Palmour
  • Publication number: 20040101625
    Abstract: A nitrided oxide layer on a silicon carbide layer is processed by annealing the nitrided oxide layer in a substantially oxygen-free nitrogen containing ambient. The anneal may be carried out at a temperature of greater than about 900° C., for example, a temperature of about 1100° C., a temperature of about 1200° C. or a temperature of about 1300° C. Annealing the nitrided oxide layer may be carried out at a pressure of less than about 1 atmosphere, for example, at a pressure of from about 0.01 to about 1 atm or, in particular, at a pressure of about 0.2 atm. The nitrided oxide layer may be an oxide layer that is grown in a N2O and/or NO containing ambient, that is annealed in a N2O and/or NO containing ambient or that is grown and annealed in a N2O and/or NO containing ambient.
    Type: Application
    Filed: August 14, 2003
    Publication date: May 27, 2004
    Inventors: Mrinal Kanti Das, Adam William Saxler
  • Publication number: 20030160274
    Abstract: Capacitors and interconnection structures for silicon carbide are provided having an oxide layer, a layer of dielectric material and a second oxide layer on the layer of dielectric material. The thickness of the oxide layers may be from about 0.5 to about 33 percent of the thickness of the oxide layers and the layer of dielectric material. Capacitors and interconnection structures for silicon carbide having silicon oxynitride layer as a dielectric structure are also provided. Such a dielectric structure may be between metal layers to provide a metal-insulator-metal capacitor or may be used as a inter-metal dielectric of an interconnect structure so as to provide devices and structures having improved mean time to failure. Methods of fabricating such capacitors and structures are also provided.
    Type: Application
    Filed: March 6, 2003
    Publication date: August 28, 2003
    Inventors: Mrinal Kanti Das, Lori A. Lipkin, John W. Palmour, Scott Sheppard, Helmut Hagleitner
  • Publication number: 20020102358
    Abstract: Silicon carbide structures are fabricated by fabricating a nitrided oxide layer on a layer of silicon carbide and annealing the nitrided oxide layer in an environment containing hydrogen. Such a fabrication of the nitrided oxide layer may be provided by forming the oxide layer in at least one of nitric oxide and nitrous oxide and/or annealing an oxide layer in at least one of nitric oxide and nitrous oxide. Alternatively, the nitrided oxide layer may be provided by fabricating an oxide layer and fabricating a nitride layer on the oxide layer so as to provide the nitrided oxide layer on which the nitride layer is fabricated. Furthermore, annealing the oxide layer may be provided as a separate step and/or substantially concurrently with another step such as fabricating the nitride layer or performing a contact anneal. The hydrogen environment may be pure hydrogen, hydrogen combined with other gases and/or result from a hydrogen precursor. Anneal temperatures of 400° C. or greater are preferred.
    Type: Application
    Filed: October 26, 2001
    Publication date: August 1, 2002
    Inventors: Mrinal Kanti Das, Lori A. Lipkin
  • Publication number: 20020072247
    Abstract: Methods for fabricating a layer of oxide on a silicon carbide layer are provided by forming the oxide layer on the silicon carbide layer by oxidizing the silicon carbide layer in an N2O environment. A predetermined temperature profile and/or a predetermined flow rate profile of N2O are provided during the oxidation. The predetermined temperature profile and/or predetermined flow rate profile may be constant or variable and may include ramps to steady state conditions. The predetermined temperature profile and/or the predetermined flow rate profile are selected so as to reduce interface states of the oxide/silicon carbide interface with energies near the conduction band of SiC.
    Type: Application
    Filed: October 1, 2001
    Publication date: June 13, 2002
    Inventors: Lori A. Lipkin, Mrinal Kanti Das, John W. Palmour
  • Publication number: 20020038891
    Abstract: Silicon carbide metal-oxide semiconductor field effect transistors (MOSFETs) and methods of fabricating silicon carbide MOSFETs are provided. The silicon carbide MOSFETs have an n-type silicon carbide drift layer, spaced apart p-type silicon carbide regions in the n-type silicon carbide drift layer and having n-type silicon carbide regions therein, and a nitrided oxide layer. The MOSFETs also have n-type shorting channels extending from respective ones of the n-type silicon carbide regions through the p-type silicon carbide regions to the n-type silicon carbide drift layer. In further embodiments, silicon carbide MOSFETs and methods of fabricating silicon carbide MOSFETs are provided that include a region that is configured to self-deplete the source region, between the n-type silicon carbide regions and the drift layer, adjacent the oxide layer, upon application of a zero gate bias.
    Type: Application
    Filed: July 24, 2001
    Publication date: April 4, 2002
    Inventors: Sei-Hyung Ryu, Anant Agarwal, Mrinal Kanti Das, Lori A. Lipkin, John W. Palmour, Ranbir Singh
  • Publication number: 20020030191
    Abstract: Capacitors and interconnection structures for silicon carbide are provided having an oxide layer, a layer of dielectric material and a second oxide layer on the layer of dielectric material. The thickness of the oxide layers may be from about 0.5 to about 33 percent of the thickness of the oxide layers and the layer of dielectric material. Capacitors and interconnection structures for silicon carbide having silicon oxynitride layer as a dielectric structure are also provided. Such a dielectric structure may be between metal layers to provide a metal-insulator-metal capacitor or may be used as a inter-metal dielectric of an interconnect structure so as to provide devices and structures having improved mean time to failure. Methods of fabricating such capacitors and structures are also provided.
    Type: Application
    Filed: June 12, 2001
    Publication date: March 14, 2002
    Inventors: Mrinal Kanti Das, Lori A. Lipkin, John W. Palmour, Scott Sheppard, Helmut Hagleitner