Propagation in layered biased semiconductor structures based on transport analysis

A transport-field parallel-plate formulation and solution method to determine the small-signal propagation constant is given for wide microstrip lines over an inhomogeneously doped semiconductor substrate of small transverse dimensions. Included in the detailed transport model are two carrier species, recombination-generation mechanisms, DC and AC field-dependent mobilities and diffusion constants, and boundary condition contact effects. A transverse DC bias condition is applied. Structures numerically simulated are a voltage-variable GaAs distributed Schottky-barrier phase shifter and a transmission line over an Si bipolar junction. Numerical data based on a finite-difference technique are generated on carrier densities, electric potentials and fields, and current densities. Propagation constant calculations compared favorably to those calculated by both full-wave field analysis and moments-of-the-Boltzmann-equation analysis for some less general cases. Propagation constant results for the GaAs structure are compared with available experimental data, and good agreement is obtained.<>