The thermal stability of strained-Si/Si0.7Ge0.3 heterostructures was investigated by means of secondary-ion mass spectroscopy, Raman spectroscopy and atomic force microscopy. It was noted that Ge atoms diffused out through the strained-Si layer during heat treatment (1000C, 1h). The activation energy for Ge diffusion in the strained Si was equal to 3.3eV (figure 2). This value was lower than those (4.7 to 5.3eV) for unstrained Si. The strain in the Si layers did not change after heat treatment, at up to 950C, for 1h. Slip lines, which were due to strain relaxation, formed at the surfaces of strained Si layers when samples were treated at 950 to 1000C for 1h.

Thermal Stability of the Strained-Si/SiGe Heterostructure. N.Sugii: Journal of Applied Physics, 2001, 89[11], 6459-63