Abstract: We report results about the strain and annealing effects for a SiGe/Si structure grown in micron-sized windows by MBE.Experiments show that the strain of the SiGe film in the window is significantly different from that of the film grown on an unpatterned area on the same substrate,the former of which depends not only on the size of the window but also on the stress of the mask material of the window.Experiments also show that the edge effects significantly affect the thermal stability of the Si0.8Ge0.2 film in the window.For Si0.8Ge0.2 film in a window of 3μm×3μm,its strain is relaxed by only less than 4% after the sample is annealed at 950℃ for 30min,which is much less than the strain relaxation of the Si0.8Ge0.2 film grown on the unpatterned area on the same substrate under the same annealing condition.We discuss the possible reasons for these results.

Key words: SiGe, strain, dislocation, MBE