ELLIPSOMETRIC DETERMINATION OF THE DEFECT STRUCTURE OF Cz-Si SAMPLES ANNEALED AT T ≥ 450℃ UNDER UNIFORM STRESS CONDITIONS

摘要

The ellipsometry was applied to study the defect structure of Czochralski grown silicon subjected to hydrostatic pressure up to 1.1 GPa at (450/1350)℃. The one- or two-steps preannealing treatment at 1E5 Pa was applied sometimes to create oxygen - related defects. The theoretical model of defects as the spherical disturbances of material has been assumed. The influence of defects size and density on ellipsometric parameters has been analysed. High pressure-high temperature (HP-HT) treatment of as-grown Cz-Si samples at ≤ 957℃ resulted in increase of defect density with decrease of defect dimensions. HP-HT treatment of the Cz-Si samples with thermal donorsucleation centres for oxygen precipitation or of that with large oxygen precipitates resulted typically in the same effect. The results of the HP-HT treatment at 1280/1350℃ were of more complicated pattern. The defects density and dimensions value determined by ellipsometry were compared with that obtained by other methods.