Lateral transport was investigated in films which had been produced by electron cyclotron resonance plasma-assisted molecular beam epitaxy, and were doped n-type by 1015 to 1020/cm3Si. The room-temperature electron mobility, as a function of carrier concentration, was found to describe a family of bell-shaped curves. This was consistent with a proposed model for scattering by charged dislocations. The mechanism of this scattering was investigated by studying the temperature dependences of the carrier concentration and electron mobility. It was found that, in the low carrier concentration region (below 1017/cm3), the electron mobility was thermally activated. Overall, the temperature dependence of the mobility in samples where dislocations played a predominant role showed that the mobility did not follow classical behavior but was thermally activated; with an activation energy which was half of that predicted on the basis of the temperature dependence of the carrier concentration.

H.M.Ng, D.Doppalapudi, T.D.Moustakas, N.G.Weimann, L.F.Eastman: Applied Physics Letters, 1998, 73[6], 821-3