Diffusion enhanced carbon loss from SiGeC layers due to oxidation - art. no. 073308

The effect of annealing 25-nm-thick pseudomorphic Si0.7865Ge0.21C0.0035 lay ers on silicon substrates in nitrogen or oxygen at 850 degreesC was examine d for different silicon cap thicknesses and annealing times by x-ray diffra ction and secondary-ion mass spectrometry. Carbon is found to diffuse rapid ly out of the SiGeC layer and even out of the sample entirely, an effect th at is enhanced by oxidation and thin cap layers. All substitutional carbon can be removed from the sample in some cases, implying negligible formation of silicon-carbon complexes. Furthermore, it is found that each injected s ilicon interstitial atom due to oxidation causes the removal of one additio nal carbon atom for the SiGeC layer.