Patents by Inventor Hassan Pirastehfar

Hassan Pirastehfar 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).

  • Method of making a structure for top surface gettering of metallic impurities
    Patent number: 5556793
    Abstract: A method for gettering metallic impurities from a semiconductor substrate (25). A gettering structure is fabricated in inactive areas of a semiconductor chip (31). The gettering structure is manufactured by forming an oxide (30) having a bird's head structure contacting a heavily doped region (28). The combination creates precipitation nuclei to which the metallic impurities migrate. The metallic impurities are sequestered by the precipitation nuclei or trap sites and rendered incapable of degrading the electrical characteristics of a semiconductor device.
    Type: Grant
    Filed: November 1, 1993
    Date of Patent: September 17, 1996
    Assignee: Motorola, Inc.
    Inventors: Steven J. Adler, George W. Hawkins, Israel A. Lesk, Peter L. Pegler, Hassan Pirastehfar
  • Field plate avalanche diode
    Patent number: 5434442
    Abstract: A field plate avalanche diode has a field plate extending over the breakdown PN junction.
    Type: Grant
    Filed: May 11, 1992
    Date of Patent: July 18, 1995
    Assignee: Motorola, Inc.
    Inventors: Israel A. Lesk, Hassan Pirastehfar
  • Double implanted laterally diffused MOS device and method thereof
    Patent number: 5371394
    Abstract: An NMOS transistor has a source and a drain composed of n+ type of semiconductor material. A substrate region composed of a p type of semiconductor material is disposed between the source and the drain. A gate region is disposed above the substrate region and between the source region and the drain region. A first implant region is disposed adjacent to the source region and the gate region. The first implant region is composed of p type of semiconductor material with a first doping concentration. A second implant region is disposed between the first implant region and the substrate. The second implant region is composed of p type of semiconductor material with a second doping concentration. The channel doping profile first and second implant regions is tailored to obtain the optimum internal electric field to maximize device transconductance, while simultaneously controlling the device threshold voltage and punch through characteristics.
    Type: Grant
    Filed: November 15, 1993
    Date of Patent: December 6, 1994
    Assignee: Motorola, Inc.
    Inventors: Gordon C. Ma, Hassan Pirastehfar, Steven J. Adler
  • Low on resistance field effect transistor
    Patent number: 5252848
    Abstract: A performance enhancing conductor (27) is employed to reduce a transistor's (10) on resistance and to also reduce the transistor's (10) parasitic gate to drain capacitance (32). The performance enhancing conductor (27) covers the transistor's (10) gate (22) and a portion of the drain region (18, 19) that is adjacent the transistor's channel (20). The performance enhancing conductor (27) is isolated from the gate (22) by an insulator (24, 26).
    Type: Grant
    Filed: February 3, 1992
    Date of Patent: October 12, 1993
    Assignee: Motorola, Inc.
    Inventors: Steven J. Adler, Robert B. Davies, Stephen J. Nugent, Hassan Pirastehfar
  • High frequency photo detector and method for the manufacture thereof
    Patent number: 4961097
    Abstract: An improved photo detector is provided by forming a tub of monocrystalline semiconductor material surrounded by a layer of monocrystalline material of opposite conductivity type. The improved structure is manufactured by means of a modified DIC process. The device may by made deep enough to absorb a large portion of the incident radiation near the PN junction without sacrificing a large number of photo-generated carriers to recombination.
    Type: Grant
    Filed: March 11, 1985
    Date of Patent: October 2, 1990
    Assignee: Motorola Inc.
    Inventors: Hassan Pirastehfar, George C. Onodera, Waisiu Law, David M. Heminger