Results from X-ray diffraction studies of the morphology of the growing Si(001 )/SiO2 interface are presented. We show the evolution of the root mean square roughness as a function of the growth variables, and we try to go beyond the root mean square parametrization of the interface by measuring the spectral distribution of interface fluctuations. Within our current experimental sensitivies we cannot resolve any fluctuations with a finite in-plane momentum transfer.

Root mean square measurements of the Si(001)/SiO2 interface have been performed with a variety of techniques. Using X-ray diffraction to represent the diffraction class of techniques, and atomic force microscopy to represent imaging techniques, we discuss the effect that limitations of each technique have on experimental results.

We use synchrotron X-ray diffraction to non-destructively characterize the roughness of various Si(001) interfaces. On the same sample, we compare the roughness of a buried Si(001)/SiO2 interface with the clean, reconstructed Si(001)/vacuum interface formed by desorption of the oxide. We also compare three different types of oxide; a native oxide, a dry thermal oxide, and a chemically grown RCA-clean type of oxide. We show that the dry thermal oxide interface is 0.5±0.1 times as rough as the native oxide interface, suggesting that the oxide growth decreases the roughness slightly.