Abstract
The techniques of grazing incidence x-ray scattering and Ge Kα fluorescence were applied to a study of buried ultrathin Ge layers grown on bulk Si(100) substrate. Using these methods, it was shown that buried ultrathin Ge layer MBE grown on si can have a reasonably sharp interface under proper growth conditions. The roughness at neighboring interfaces were conformal. The lateral correlation length of interfacial roughness was on the order of several thousand angstrom. For extremely thin 4 angstrom Ge layer, a simple one-layer model with interfacial roughness cannot account for the observed scattering effects due to the possibilities of developing a discontinuous layer with large roughness on interdiffusion at the interfaces. When the Ge thickness neared the critical thickness, significant alterations in the global interfacial microstructures can take place, which can be detected as a precursor by the x-ray scattering measurements.