The strained Si/Si1–xGex/Si layer heterostructure heat treated from 700 to 950C in Ar (annealing) or O2–C2H2Cl2 (oxidation) was characterized using high-resolution X-ray diffraction in combination with Rutherford backscattering. Only small changes to the structure were observed up to 800C, within the resolution limits of diffraction and backscattering. Severe strain relaxation occurred at 950C and the heterostructure tends to relax more during annealing in Ar than during oxidation in O2–C2H2Cl2. The strain relaxation was mainly caused by interdiffusion of Si and Ge rather than formation of misfit dislocations. Diffusion of Si interstitials generated during oxidation into the heterostructure was suggested as the cause responsible for the less pronounced interdiffusion of Si and Ge in the oxidized samples.

Characterization of Strained Si/Si1–xGex/Si Heterostructures Annealed in Oxygen or Argon. A.C.Lindgren, C.Chen, S.L.Zhang, M.Östling, Y.Zhang, D.Zhu: Journal of Applied Physics, 2002, 91[5], 2708-12