RELAXED SI1-XGEX FILMS WITH REDUCED DISLOCATION DENSITIES GROWN BY MOLECULAR-BEAM EPITAXY

The quality of annealed Si0.86Ge0.14 films grown on thin bond-etchback silicon on insulator (BESOI) wafers has been investigated using photo luminescence and X-ray diffraction techniques. We present evidence for the relaxation of these layers under conditions which result in highe r film quality than for the same layers grown on bulk Si. The surmised mechanism leading to the reduced dislocation density is the viscous f low of the buried SiO2 layer, which allows strain in the Si0.86Ge0.14 layer to be relaxed by the introduction of dislocations primarily in t he thin Si layer.