Patents Examined by C. Chaudhori
  • Patent number: 5362685
    Abstract: The quality of both a gate oxide and a tunnel oxide in a P-well active area of a CMOS EEPROM process is improved by reducing the field edge pullback arising from wet chemical etch steps prior to the growth of the gate and tunnel oxides. A first oxide is grown, and an implant is performed through the first oxide to form an implanted layer. The surface of the first oxide is then cleaned without removing all of the first oxide overlying the implanted layer. An anneal step then activates the implanted layer to form a heavily-doped region, after which the remaining first oxide is then removed. A second oxide is then grown, and a region of the second oxide is removed overlying the heavily-doped region. Lastly, a tunnel oxide is grown over the heavily-doped region while re-oxidizing the second oxide to form a gate oxide thicker than the tunnel oxide.
    Type: Grant
    Filed: October 29, 1992
    Date of Patent: November 8, 1994
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Mark I. Gardner, Henry J. Fulford, Jr., Jay J. Seaton