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 method of removing the native oxide. The evolution of the surface roughness of 1 μm thick GaAs films grown at 553°C was monitored in real time using ultraviolet light scattering, and compared with ex situ atomic force microscopy measurements of the power spectral density (PSD) of the surface morphology. The PSD at a spatial frequency of 2 μm−1, is approximately three orders of magnitude larger for films grown on thermally cleaned substrates than for films grown on substrates cleaned with atomic hydrogen. No mounding indicative of unstable growth was observed in the films cleaned with atomic hydrogen.