The structural properties of SiGe layers, which had been grown epitaxially onto Si(100) by ion beam sputter deposition, were studied as a function of the growth temperature and film thickness. It was shown that the structure of the defects depended strongly upon the growth temperature. A dislocation cross-grid, which was observed at the SiGe/Si interface in layers which had been grown at high temperatures (700C), was missing from layers which had been grown at low temperatures (up to 550C). A new type of defect, that was parallel to {001} and {113} lattice planes, appeared at these temperatures. The optimal growth temperature, for a Ge content of 20 to 25at%, was found to be of the order of 550 to 625C. Photoluminescence studies revealed, apparently for the first time, 2 peaks on the low-energy side of the Si(TO) peak of the epilayers. Changes in the intensity of these peaks were strongly related to the dynamics of strain relaxation, and could be attributed to a set of dislocations at the SiGe/Si interface which extended both to the epilayer and to the bulk Si.

M.Lyakas, T.Arazi, M.Eizenberg, V.Demuth, H.P.Strunk, N.Mosieh, F.Meyer, C.Schwebel: Journal of Applied Physics, 1995, 78[8], 4975-81