Electron paramagnetic resonance data indicated the existence of more than 1016/cm3 of intrinsic defects (self-interstitials) in float-zone or Czochralski crystals of Au-doped or Pt-doped material which had been quenched from 1300C. Although the self-interstitials could not be detected directly by means of electron paramagnetic resonance, they modified the hyperfine structure of P donors. At temperatures near to 500C, these interstitials caused a shift in the Fermi level, as monitored by monitoring the well-known electron paramagnetic resonance spectrum of isolated substitutional Pt atoms. The self-interstitial related defects which were responsible for the Fermi level shift were not observed by using electron paramagnetic resonance methods. They were assumed to be formed by the complexing of self-interstitials with each other or, more probably, with non-magnetic Pt defects such as Pt-Pt pairs. The tendency to form 2-Pt defects was emphasized by the detection of 2 further paramagnetic 2-Pt defects in addition to the 2 pair defects which were already known. It was suggested that the self-interstitials took part in the formation of the 3 types of 6-Pt clusters which were observed after lengthier annealing at 540C.

J.Juda, M.Höhne: Solid State Phenomena, 1996, 47-48, 293-8