Direct Observation of Intermixing at Ge/Si(001) Interfaces by High-Resolution Rutherford Backscattering Spectroscopy

Abstract
The initial stage of Ge/Si(001) epitaxial growth is studied with high-resolution Rutherford backscattering spectroscopy. In contrast to the generally accepted picture, intermixing of Ge and Si begins before the first layer is completed at the growth temperature of 500 °C. If the layer is deposited at room temperature, intermixing takes place during annealing at 300–800 °C. These observations are in reasonable agreement with a recent theoretical study based on generalized gradient approximation density functional calculations [Y. Yoshimoto and M. Tsukada, Surf. Sci. 423, 32 (1999)].