Influence of tin impurities on the generation and annealing of thermal oxygen donors in Czochralski silicon at 450 degrees C

The beneficial influence of Sn doping of Si materials on the radiation hard ness has triggered interest in this material. It is therefore essential to have a good insight in the impact of Sn on the fundamental defect behavior. This report gives a systematic study of the effect of the Sn impurities bn the generation and annealing kinetics of oxygen-containing thermal donors formed during a 450 degrees C anneal step. Special attention is given to th e influence of a thermal preheat treatment at 800 degrees C and the importa nt role played by oxygen microfluctuations. The latter act as precursors fo r the thermal donor formation. The original Kaiser-Frisch-Reiss model, deve loped fur explaining the experimental results in Sn-free Czochralski Si and based on hetero- and homogeneous precipitation processes, points to the be neficial role of Sn doping on the thermal donor properties. (C) 2000 The El ectrochemical Society. S0013-4651(99)12-065-2. All rights reserved.