Calculation of the mobility and the Hall factor for dopedp-type silicon

Conductivity and Hall mobilities have been calculated for nondegenerately doped p-type silicon. In addition to the two-phonon scattering mechanisms already incorporated by the author earlier [Phys. Rev. B 28, 5973 (1983)], the ionized- and neutral-impurity scattering are also included. Care has been taken to include many contributions arising from the anisotropic-nonparabolic nature of the bands in modeling the transport. Results of the calculation are compared with data on boron-, aluminum-, gallium-, and indium-doped silicon. The comparison indicates that the Brooks-Herring model, modified to incorporate nonparabolic and most of the anisotropic effects, agrees well with experiments. On the other hand, it is shown that current models of neutral-impurity scattering are not sufficiently accurate as yet. A theory due to Ralph can, with one adjustable parameter, be made to give good agreement with experiments. The calculated ratio of the Hall mobility to the conductivity mobility, the so-called r factor, has been used to obtain the hole concentrations from the Hall-coefficient data. Least-squares fitting of the charge-balance equation to the hole-concentration data as a function of temperature produces superior χ² and acceptor activation energies compared to those resulting from the use of the r=1 approximation.