Isolated Ti in Si: Deep level transient spectroscopy, minority carrier transient spectroscopy, and high-resolution Laplace deep level transient spectroscopy studies

Abstract

Combining deep level transient spectroscopy (DLTS), high-resolution Laplace DLTS, and minority carrier transient spectroscopy studies, we question the identification of the dominant Ti-related defects introducing deep levels (E40, E150, and H180) in n- and p-type Si. The observed results cannot unambiguously support the models previously reported for these defects. The presence of the Poole-Frenkel effect describing the enhancement of the emission rates of E40 as a function of electric field is not consistent with the previous assignment of this defect to the single acceptor, whereas the absence of the enhancement of the emission rate of E150 under different reverse bias applied to the diode does not confirm the previous attribution of this defect to the single donor in n-type Si. The attribution of H180 to the double donor is in good agreement with our results. In contrast, the identical depth profiles obtained for E40 and E150 in bulk of as-grown, hydrogenated and annealed samples cannot be explained by the assignment of these levels to different defects.