High Electron Mobility in p-Type III-V Compound Semiconductors

Electron scattering by impurities in degenerate semiconductors is calculated by a simplified square well-or-hump potential model. For various III-V compound semiconductors with large hole-to-electron mass ratios m h/m e, it is found that the scattering cross-section by a screened acceptor is much smaller than that by a screened donor. The donor-to-acceptor ratio of the cross-sections σD/σA amounts to 550 in InSb at a carrier density of 1018 cm-3. A simple relation σD/σ A ∝(m h/m e)2 exists over the available III-V compounds. The absolute magnitude of the cross-section is also discussed in conjunction with the pseudo-neutral impurity scattering model.