Patents by Inventor Gary E. Bulman

Gary E. Bulman 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: 5838706
    Abstract: A Group III nitride laser structure is disclosed with an active layer that includes at least one layer of a Group III nitride or an alloy of silicon carbide with a Group III nitride, a silicon carbide substrate, and a buffer layer between the active layer and the silicon carbide substrate. The buffer layer is selected from the group consisting of gallium nitride, aluminum nitride, indium nitride, ternary Group III nitrides having the formula A.sub.x B.sub.1-x N, where A and B are Group III elements and where x is zero, one, or a fraction between zero and one, and alloys of silicon carbide with such ternary Group III nitrides. In preferred embodiments, the laser structure includes a strain-minimizing contact layer above the active layer that has a lattice constant substantially the same as the buffer layer.
    Type: Grant
    Filed: November 19, 1996
    Date of Patent: November 17, 1998
    Assignee: Cree Research, Inc.
    Inventors: John Adam Edmond, Gary E. Bulman, Hua-Shuang Kong
  • Patent number: 5592501
    Abstract: A Group III nitride laser structure is disclosed with an active layer that includes at least one layer of a Group III nitride or an alloy of silicon carbide with a Group III nitride, a silicon carbide substrate, and a buffer layer between the active layer and the silicon carbide substrate. The buffer layer is selected from the group consisting of gallium nitride, aluminum nitride, indium nitride, ternary Group III nitrides having the formula A.sub.x B.sub.1-x N, where A and B are Group III elements and where x is zero, one, or a fraction between zero and one, and alloys of silicon carbide with such ternary Group III nitrides. In preferred embodiments, the laser structure includes a strain-minimizing contact layer above the active layer that has a lattice constant substantially the same as the buffer layer.
    Type: Grant
    Filed: September 20, 1994
    Date of Patent: January 7, 1997
    Assignee: Cree Research, Inc.
    Inventors: John A. Edmond, Gary E. Bulman, Hua-Shuang Kong
  • Patent number: 5523589
    Abstract: A light emitting diode emits in the blue portion of the visible spectrum and is characterized by an extended lifetime. The light emitting diode comprises a conductive silicon carbide substrate; an ohmic contact to the silicon carbide substrate; a conductive buffer layer on the substrate and selected from the group consisting of gallium nitride, aluminum nitride, indium nitride, ternary Group III nitrides having the formula A.sub.x B.sub.1-x N, where A and B are Group III elements and where x is zero, one, or a fraction between zero and one, and alloys of silicon carbide with such ternary Group III nitrides; and a double heterostructure including a p-n junction on the buffer layer in which the active and heterostructure layers are selected from the group consisting of binary Group III nitrides and ternary Group III nitrides.
    Type: Grant
    Filed: September 20, 1994
    Date of Patent: June 4, 1996
    Assignee: Cree Research, Inc.
    Inventors: John A. Edmond, Gary E. Bulman, Hua-Shuang Kong, Vladimir Dmitriev
  • Patent number: 5338944
    Abstract: A light emitting diode is disclosed that emits light in the blue region of the visible spectrum with increased brightness and efficiency. The light emitting diode comprises an n-type silicon carbide substrate; an n-type silicon carbide top layer; and a light emitting p-n junction structure between the n-type substrate and the n-type top layer. The p-n junction structure is formed of respective portions of n-type silicon carbide and p-type silicon carbide. The diode further includes means between the n-type top layer and the n-type substrate for coupling the n-type top layer to the light-emitting p-n junction structure while preventing n-p-n behavior between the n-type top layer, the p-type layer in the junction structure, and the n-type substrate.
    Type: Grant
    Filed: September 22, 1993
    Date of Patent: August 16, 1994
    Assignee: Cree Research, Inc.
    Inventors: John A. Edmond, Hua-Shuang Kong, Vladimir Dmitriev, Gary E. Bulman