The effect of annealing 25nm-thick pseudomorphic Si0.7865Ge0.21C0.0035 layers on Si substrates in N or O at 850C was examined for different Si cap thicknesses and annealing times by X-ray diffraction and secondary-ion mass spectrometry. The C was found to diffuse rapidly out of the SiGeC layer, and even out of the sample entirely; an effect that was enhanced by oxidation and thin cap layers. All substitutional C could be removed from the sample in some cases, implying negligible formation of Si-C complexes. Furthermore, it was found that each injected Si interstitial atom due to oxidation caused the removal of one additional C atom from the SiGeC layer.

Diffusion Enhanced Carbon Loss From SiGeC Layers Due to Oxidation. M.S.Carroll, J.C.Sturm, E.Napolitani, D.De Salvador, M.Berti, J.Stangl, G.Bauer, D.J.Tweet: Physical Review B, 2001, 64[7], 073308 (4pp)