Patents Assigned to ASB Inc.
  • Patent number: 6562688
    Abstract: Disclosed are a method for manufacturing a homojunction or heterojunction bipolar device and a structure of the bipolar device manufactured by the method.
    Type: Grant
    Filed: December 21, 2000
    Date of Patent: May 13, 2003
    Assignee: ASB, Inc.
    Inventors: Tae-Hyeon Han, Byung Ryul Ryum, Soo-Min Lee, Deok-Ho Cho
  • Patent number: 6552374
    Abstract: Disclosed are a method for forming a base layer by epitaxial growth technology of a heterojunction bipolar device and a structure of the bipolar device manufactured by the method.
    Type: Grant
    Filed: January 17, 2001
    Date of Patent: April 22, 2003
    Assignee: ASB, Inc.
    Inventors: Tae-Hyeon Han, Byung Ryul Ryum, Soo-Min Lee, Deok-Ho Cho
  • Patent number: 6462397
    Abstract: The present invention is related to a bipolar transistor in which the in-situ doped epitaxial Si or SiGe base layer is used instead of using an ion-implanted Si base, in order to achieve higher cutoff frequency. The SiGe base having the narrower energy bandgap than the Si emitter allows to enhance the current gain, the cutoff frequency(fT), and the maximum oscillation frequency (fmax). The narrow bandgap SiGe base also allows to have higher base doping concentration. As a result, the intrinsic base resistance is lowered and the noise figure is thus lowered. Parasitic base resistance is also minimized by using a metallic silicide base ohmic electrode. The present invention is focused on low cost, high repeatability and reliability by simplifying the manufacturing process step.
    Type: Grant
    Filed: October 22, 2001
    Date of Patent: October 8, 2002
    Assignee: ASB, Inc.
    Inventors: Byung Ryul Ryum, Tae Hyeon Han, Soo Min Lee, Deok Ho Cho
  • Patent number: 6362066
    Abstract: The present invention is related to a bipolar transistor in which the in-situ doped epitaxial Si or SiGe base layer is used instead of using an ion-implanted Si base, in order to achieve higher cutoff frequency. The SiGe base having the narrower energy bandgap than the Si emitter allows to enhance the current gain, the cutoff frequency (fT), and the maximum oscillation frequency (fmax). The narrow bandgap SiGe base also allows to have higher base doping concentration. As a result, the intrinsic base resistance is lowered and the noise figure is thus lowered. Parasitic base resistance is also minimized by using a metallic silicide base ohmic electrode. The present invention is focused on low cost, high repeatability and reliability by simplifying the manufacturing process step.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: March 26, 2002
    Assignee: ASB Inc.
    Inventors: Byung Ryul Ryum, Tae Hyeon Han, Soo Min Lee, Deok Ho Cho