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Keywords:

  • Si;
  • Ti;
  • DLTS;
  • interstitial

Abstract

Using high-resolution Laplace DLTS studies we demonstrate that three Ti-related levels (E40, E150 and H180) previously assigned to the different charge states of the interstitial Ti belong to different Ti defects. The enhancement of the emission rates of E40 and H180 as a function of the electric field (Poole-Frenkel effect) shows that these defects are charged before they capture a majority carrier in n- and p-type Si, respectively. In contrast to the previous studies we did not observe the Poole-Frenkel effect for E150. The inconsistence is correlated with the presence of H-related defects close to E150, which cannot be distinguished by using the conventional DLTS technique. The absence of the Poole-Frenkel effect for E150 indicates that the defect is an acceptor in n-type Si. The origin of the defects will be discussed. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)