Raman study of mechanical stresses in processes of oxygen precipitation in silicon

Raman investigation of oxygen precipitation in silicon was carried out taking into consideration the stress environment of precipitates and interaction with interstitial atoms. Influence of oxygen precipitates on efficiency of stacking faults and dislocation loops formation was observed. Stresses that evolved in the precipitation process during thermal treatments were detected by Raman measurements. Strong correlation of measured stress distribution with defects distribution was obtained. A physical model was proposed incorporating stress profiles due to precipitate formation with emitted interstitial atoms, interaction of the precipitate with interstitial atoms in a deformation mechanism and growth of the precipitate surrounded by interstitial-like dislocation loops with elimination of the stress. On the basis of the suggested approach stresses were modelled for the case of a nonuniform distribution of precipitates. Comparison with Raman data provided information on stress tensors around the precipitate.