n-type modulation-doped Si/SiGe heterostructures were grown on different types of partly relaxed SiGe buffer layers, which are required in this material system to obtain a large enough conduction band offset. The samples were characterized by

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A mechanism of strain relief of H+ ion implanted and annealed pseudomorphic Si1−xGex/Si(100) heterostructures grown by molecular beam epitaxy is proposed and analyzed. Complete strain relaxation was obtained at temperatures as low as 800 °C and the samples appeared free of threading dislocations within the SiGe layer to the limit of transmission electron microscopy analysis. In our model, H filled nanocracks are assumed to generate dislocation loops, which glide to the interface where they form strain relieving misfit segments. On the basis of this assumption, the conditions for efficient strain relaxation are discussed.

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