EFFECT OF GROWTH-CONDITIONS ON THE STRUCTURAL-PROPERTIES OF ION-BEAM SPUTTER-DEPOSITED SIGE EPILAYERS

Structural properties of Si1-xGex layers epitaxially grown on Si(100) by Ion Beam Sputter Deposition were studied as a function of growth temperature and film thickness. It was shown that the structure of defects strongly depends on the growth temperature, T-g. The dislocations cross grid which is observed at the SiGe/Si interface for layers grown at high (700 degrees C) T-g is missing in layers grown at low (less than or similar to 550 degrees C) T-g while a new type of defects parallel to {001} and {113} lattice planes appear at these temperatures. The optimal T-g for a Ge content of 20-25 at. % was found to be close to 550-625 degrees C. Surface roughness for all the growth temperatures was found to be less than that for such a ''smooth'' technique as MBE. Photoluminescence studies revealed, to the best of our knowledge for the first time, two peaks on the low energy side in the neighborhood of the Si(TO) peak of the epilayers. The evolution of the intensity of these peaks is strongly correlated with the dynamics of strain relaxation and can be attributed to a set of dislocations at the SiGe/Si interface extending both to the epilayer and to the bulk Si. (C) 1995 American Institute of Physics.