By the use of thermally cracked Si2H6, the Si coverage on Ge(0 0 1) increases compared to the case using non-cracked Si,H, and the Si adsorption coverage properties exhibit self-limiting saturation behavior. In the atomic-layer epitaxy (ALE) mode, atomic layer-growth controllability is obtained with thermally cracked Si2H6. The beta(2)/beta(1) peak height ratios in the temperature programmed desorption spectra obtained from thermally crackcd-Si2H6-exposed surfaces start increasing at a similar temperature where the onset of an increase in the cracking rate from Si2H6, to SiH2 + SiH4 and the onset of an increase in Si saturation coverage upon thermally cracked-Si2H6, exposure are observed, and the beta(1)/beta(2) peak height ratios approach a value obtained from a dihydride Si(0 0 1) surface, suggesting systematically that the increase in the Si saturation coverage is related to the adsorption of the decomposed :SiH2 species and the :SiH2 species that play an important role on the growth mechanisms. The experimental and theoretical Auger clcctron spectroscopy analysis indicate that an Si/Ge interface grown by this Si ALE on Ge(00 1) is abrupt and has little segregation and intermixing. (C) 2002 Elsevier Science B.V. All rights reserved.