Patents by Inventor Kumar Pradip Roy

Kumar Pradip Roy 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: 6521496
    Abstract: A memory cell of a non-volatile memory includes a control gate oxide layer having graded portions with greatly reduced stress on a polysilicon floating gate layer. The method of making the control gate oxide layer preferably includes growing a first oxide portion by upwardly ramping the polysilicon floating gate layer to a first temperature lower than a glass transition temperature, and exposing the polysilicon floating gate layer to an oxidizing ambient at the first temperature and for a first time period. Also, the method includes growing a second oxide portion between the first oxide portion and the polysilicon floating gate layer by exposing the polysilicon floating gate layer to an oxidizing ambient at a second temperature higher than the glass transition temperature for a second time period. The second oxide portion may have a thickness in a range of about 25 to 75% of a total thickness of the graded, grown, control gate oxide layer.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: February 18, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Kumar Pradip Roy, Ranbir Singh
  • Patent number: 6509230
    Abstract: A memory cell of a non-volatile memory includes a tunnel oxide layer having graded portions with greatly reduced stress on a silicon substrate. The method of making the tunnel oxide preferably includes growing a first oxide portion by upwardly ramping the silicon substrate to a first temperature lower than a glass transition temperature, and exposing the silicon substrate to an oxidizing ambient at the first temperature and for a first time period. Also, the method includes growing a second oxide portion between the first oxide portion and the silicon substrate by exposing the silicon substrate to an oxidizing ambient at a second temperature higher than the glass transition temperature for a second time period. The second oxide portion may have a thickness in a range of about 2 to 50% of a total thickness of the graded, grown, tunnel oxide layer.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: January 21, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Kumar Pradip Roy, Ranbir Singh
  • Patent number: 6395610
    Abstract: A bipolar transistor includes an oxide layer having graded portions with greatly reduced stress on a silicon substrate. The method of making the oxide preferably includes growing a first oxide portion by upwardly ramping the silicon substrate to a first temperature lower than a glass transition temperature, and exposing the silicon substrate to an oxidizing ambient at the first temperature and for a first time period. Also, the method includes growing a second oxide portion between the first oxide portion and the silicon substrate by exposing the silicon substrate to an oxidizing ambient at a second temperature higher than the glass transition temperature for a second time period. The second oxide portion may have a thickness in a range of about 2 to 75% of a total thickness of the graded, grown, oxide layer. The step of upwardly ramping preferably includes upwardly ramping the temperature at a relatively high ramping rate to reduce any oxide formed during the upward ramping.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: May 28, 2002
    Assignee: Lucent Technologies Inc.
    Inventors: Kumar Pradip Roy, Ranbir Singh