COMPLEXING OF PLATINUM IN FLOAT-ZONE AND CZOCHRALSKI SILICON - ELECTRON-PARAMAGNETIC-RESONANCE STUDY OF 6-PLATINUM CLUSTERS AND OXYGEN RELATED 1-PLATINUM MIDGAP DEFECT

Silicon supersaturated with platinum has preferred metastable trigonal or nearly trigonal arrangements of six platinum atoms after annealing at 540 degrees C. The structure is strongly affected by oxygen or oxy gen related intrinsic defects. Co-doping with iron percents the format ion of platinum clusters, although in the temperature range of the clu stering most of the interstitial iron is expected to have been precipi tated. An oxygen related 1-Pt defect was detected by electron paramagn etic resonance (EPR). Its identification with the dominating recombina tion centre in platinum doped silicon is suggested by photo-EPR experi ments and the preliminary hypothesis of an excited spin tripler state.