Oxidation rate enhancement of SiGe epitaxial films oxidized in dry ambient

We present a study on thin oxides obtained by rapid thermal oxidation of Si1-xGex epitaxial layers. The oxidation processes were performed in dry O-2 at 1000 degreesC for times up to 600 s. Our data show an oxide growth rate enhancement with respect to pure Si. Except for a very small amount of GeO2 that is found at the surface, all the Ge is rejected towards the SiO2/SiGe interface, forming a Ge-enriched layer free of extended defects. The comparison of our results for dry processes with those reported in the literature for wet ambient supports the idea that the kinetics of SiGe oxidation is controlled by similar mechanisms in both cases, in contrast with models and interpretations so far proposed.