A Physical Model For The Base Transit-Time Of Advanced Bipolar-Transistors

    Authors

    J. J. Liou;C. S. Ho

    Comments

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    Abbreviated Journal Title

    Solid-State Electron.

    Keywords

    VELOCITY OVERSHOOT; SPEED; TECHNOLOGY; SIMULATION; BJTS; Engineering, Electrical & Electronic; Physics, Applied; Physics, ; Condensed Matter

    Abstract

    As the feature size of advanced bipolar junction transistors (BJTs) continues to scale down, the effects of nonuniform base doping, high-level injection, current-induced base pushout, and velocity overshoot all become prominent. These effects influence strongly the switching speed of the BJT as well as the gate delay of the BICMOS. We study in detail the base transit time tau(B), which is often the limiting factor of the BJTs total delay time when the current density is high, and develop an analytical tau(B) model valid for arbitrary levels of injection and Gaussian base doping profile. For the devices considered, our calculations show that the conventional model (considers uniform base doping profile and no base pushout) overestimates tau(B) by a factor of about 2.5 at low injection and underestimates tau(B) by a factor of about 1.5 at high injection. The present model compares favorably with experimental data measured from a 0.12 mu base width BJT.

    Journal Title

    Solid-State Electronics

    Volume

    38

    Issue/Number

    1

    Publication Date

    1-1-1995

    Document Type

    Article

    Language

    English

    First Page

    143

    Last Page

    147

    WOS Identifier

    WOS:A1995QC42000021

    ISSN

    0038-1101

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