Strain relaxation and misfit dislocation in SiGe epilayers grown in micronsize windows by MBE

Strain relaxation and misfit dislocation density in Si0.8Ge0.2 epilayers gr own in micron size windows by MBE are studied. Reduction of misfit dislocat ion density and increment of strain relaxation in Si0.8Ge0.2/Si heterostruc ture grown by MBE in the windows smaller than 20 x 20 mum(2) were clearly o bserved. Besides, experiments showed that dislocation density in SiGe films would be different due to the different stress in the mask materials while the window size and the composition x of the SixGe1-x films were the same. Qualitative explanations for these experimental results are discussed. (C) 2001 Published by Elsevier Science B.V.