Kinetics of wet oxidation at 1000 °C of Si0.5Ge0.5 relaxed alloy

The wet oxidation at 1000 degrees C of Si0.5Ge0.5 relaxed alloy layers has been investigated using Rutherford backscattering spectrometry. In order to quantify the process, three sets of samples have been studied, namely thick films of Si0.5Ge0.5 alloy with and without a silicon capping layer and also bulk silicon. Consistent with previous reports germanium in the alloy is rejected from the growing oxide and plies up in the underlying alloy during oxidation. The oxidation of the uncapped Si0.5Ge0.5 alloy has a higher oxidation rate than bulk silicon while the capped alloy layer oxidizes at the same rate as bulk silicon. This different behaviour between capped and uncapped samples during wet oxidation at 1000 degrees C is described in terms of a time-dependent two-stage processes, where the oxidation rate is controlled during stages and 2 by the availability of mobile silicon and oxygen atoms, respectively.