Effect of the starting surface on the morphology of MBE-grown GaAs

In this paper, we study the homoepitaxial growth of GaAs by molecular beam epitaxy on substrates that have different pre-growth roughness due to the m ethod of removing the native oxide. The evolution of the surface roughness of 1 mu m thick GaAs films grown at 553 degrees C was monitored in real tim e using ultraviolet light scattering, and compared with ex situ atomic forc e microscopy measurements of the power spectral density (PSD) of the surfac e morphology. The PSD at a spatial frequency of 2 mu m(-1), is approximatel y three orders of magnitude larger for films grown on thermally cleaned sub strates than for films grown on substrates cleaned with atomic hydrogen. No mounding indicative of unstable growth was observed in the films cleaned w ith atomic hydrogen. (C) 2000 Elsevier Science S.A. All rights reserved.