It was shown that the use of conventional analytical procedures to determine defect parameters from deep-level transient spectra could lead to erroneous results for high-resistivity semiconductors. The effect was observed when the temperature range of a deep-level transient spectroscopy peak encompasses the temperature at which the equilibrium Fermi level intersects the energy level of defect under study. Based on this Fermi level effect, a procedure was proposed to determine the occupancy levels for defects with a strong temperature dependence of the carrier capture cross-section. It was found that the procedure could be useful for characterization of positive-U states through to negative-U centres in semiconductors.

Application of DLTS and Laplace-DLTS to Defect Characterization in High-Resistivity Semiconductors. L.F.Makarenko, J.H.Evans-Freeman: Physica B, 2007, 401-402, 666-9