ABSTRACT
We apply He implantation and subsequent annealing to MBE grown pseudomorphic Si1-xGex /Si(100) heterostructures to induce strain relief. The He implant is located slightly below the Si1-xGex/Si(100) interface. Through structural characterization by transmission electron microscopy, X-ray diffraction and Rutherford-backscattering we investigate the strain relaxation mechanism of the Si1-xGex buffer. The variation of the implantation dose and the annealing conditions change the characteristics of the dislocation configuration and of the He bubble structure. At a dose of 2×1016 cm−2 a high degree of relaxation is accompanied by a low density of threading dislocations of about 107 cm−2 for a Ge content of 30%.
