Regional Monte Carlo modeling of electron transport and transit-time estimation in graded-base HBT's

Steady-state electron transport in graded-base heterojunction bipolar transistors is investigated using a regional ensemble Monte Carlo approach. Besides the graded band and scattering parameters already incorporated in the particle model, emitter-base and collector-base junctions are also considered in the boundary conditions for carrier injection/absorption. It is shown that optimum base transit times are directly related to the maximum average velocities, which occur at different base width-composition combinations. It also illustrates a general approach to studying electron transport in graded-band devices.<
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