<title>Relaxation mechanism of SiGe thin film on SOI substrate</title>

A different annealing method for the Si/SiGe bilayer fabricated on SIMOX wafer is proposed. After annealing for a short time, the Si/SiGe bilayer relaxes via the gliding motion of dislocations in the Si layer exclusively, leaving the top SiGe layer relaxed and mostly dislocation free. In addition, Ge does not diffuse into the top Si layer of SOI substrate to assist in the relaxation of the structure at the highest annealing temperature. At low annealing temperature, SiO₂ is not expected to be viscous, and so the strain ratio is reduced in a linear fashion between 600°C and 900°C. When the annealing temperature becomes higher (for instance, 1000°C that is 58.5% of its melting point of 1710°C), the oxide can flow and the Si/SiGe bilayer behaves like a constrained thin foil slipping on the oxide. In this case, the strain ratio is dramatically reduced.