INFLUENCE OF QUASI-BALLISTIC BASE TRANSPORT ON THE SMALL-SIGNAL Y-PARAMETERS OF SI BIPOLAR-TRANSISTORS

The small-signal forward y-parameters of a Si bipolar transistor are e valuated from a 1-flux solution to the Boltzmann transport equation, F or base widths less than 0.1 mu m, results begin to deviate significan tly from those predicted by the conventional diffusion analysis, In pa rticular, the phase of the y-parameter, an important factor in analog circuit design, is shown to be especially sensitive to quasi-ballistic transport, Compact circuit models min become increasingly inaccurate as base widths continue to shrink, The approach used here eliminates t he restriction to a long base and can serve as the basis for improved compact circuit modeling.