Patents by Inventor Dev Alok

Dev Alok 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: 5449925
    Abstract: Voltage breakdown resistant monocrystalline silicon carbide semiconductor devices are obtained by forming an amorphous silicon carbide termination region in a monocrystalline silicon carbide substrate, at a face thereof, adjacent and surrounding a silicon carbide device. The amorphous termination region is preferably formed by implanting electrically inactive ions, such as argon, into the substrate face at sufficient energy and dose to amorphize the substrate face. The device contact or contacts act as an implantation mask to provide a self-aligned termination region for the device. The terminated devices may exhibit voltage breakdown resistance which approaches the ideal value for silicon carbide.
    Type: Grant
    Filed: May 4, 1994
    Date of Patent: September 12, 1995
    Assignee: North Carolina State University
    Inventors: Bantval J. Baliga, Dev Alok
  • Patent number: 5436174
    Abstract: A trench is formed in a monocrystalline silicon carbide substrate by amorphizing a portion of the monocrystalline silicon carbide substrate to define an amorphous silicon carbide region therein. The amorphous silicon carbide region is then removed, to produce a trench in the monocrystalline silicon carbide substrate corresponding to the removed amorphous silicon carbide region. The substrate may be amorphized by implanting ions into a masked substrate so that the implanted ions convert the unmasked portions of the substrate into amorphous silicon carbide. The amorphous silicon carbide may be etched using at least one etchant which etches amorphous silicon carbide relatively quickly and etches monocrystalline silicon carbide relatively slowly, such as hydrofluoric acid and nitric acid. The amorphizing and removing steps may be repeatedly performed to form deep trenches.
    Type: Grant
    Filed: January 25, 1993
    Date of Patent: July 25, 1995
    Assignee: North Carolina State University
    Inventors: Bantval J. Baliga, Dev Alok
  • Patent number: 5318915
    Abstract: A method for forming a p-n junction in silicon carbide includes the steps of amorphizing a portion of a monocrystalline silicon carbide substrate, implanting dopant ions into the amorphous portion of the substrate and then recrystallizing the amorphous portion to thereby form a substantially monocrystalline region including the dopant ions. In particular, the amorphizing step includes the steps of masking an area on the face of the monocrystalline silicon carbide substrate and then directing electrically inactive ions to the masked area so that an amorphous region in the substrate is formed. Accordingly, the amorphous region has sidewalls extending to the face that are substantially orthogonal to the bottom edge of the amorphous region. Once the amorphized region is defined, electrically active dopant ions are implanted into the amorphous region. The dopant ions are then diffused into the amorphous region and become uniformly distributed.
    Type: Grant
    Filed: January 25, 1993
    Date of Patent: June 7, 1994
    Assignee: North Carolina State University at Raleigh
    Inventors: Bantval J. Baliga, Dev Alok, Mohit Bhatnagar