Interfacial roughness of Fe_3Si/ GaAs(001) films studied by X-ray crystal truncation rods

摘要

Crystal truncation rods (CTRs) from thin Fe-3Si films grown on GaAs(001) by molecular beam epitaxy (MBE) are measured at different stages of deposition. The films do not develop their own surface roughness but are conforrnal to the substrate, so thai the substrate roughness governs the whole system. A factor that describes the roughness ol' a zinc blende structurernin the β model of terrace height probabilities is derived and applied to describe the experimental curves. We show that the β model adequately describes the CTRs while the model of continuous Gaussian fluctuations of the surface height notably underestimates the root-mean-squared (rms) roughness.