MAJORITY AND MINORITY ELECTRON AND HOLE MOBILITIES IN HEAVILY DOPED GAAS

The majority electron and minority hole mobilities have been calculated in GaAs for donor densities between 5 x 10(16) and 1 x 10(19) cm-3. Similarly, the majority hole and minority electron mobilities have been calculated for acceptor densities between 5 x 10(16) and 1 x 10(20) cm-3. All the important scattering mechanisms have been included. The ionized impurity and carrier-carrier scattering processes have been treated with a phase-shift analysis. These calculations are the first to use a phase-shift analysis for minority carriers scattering from majority carriers. The results are in good agreement with experiment, but predict that at high dopant densities minority mobilities should increase with increasing dopant density for a short range of densities. This effect occurs because of the reduction of plasmon scattering and the removal of carriers from carrier-carrier scattering because of the Pauli exclusion principle. Some recent experiments support this finding. These calculations do not treat the density-of-states modifications due to heavy doping, which should have only a small effect on the mobility at room temperature. The results are important for device modeling because of the need to have values for minority mobilities.