Technology computer aided design based deep level transient spectra: Simulation of high-purity germanium crystals

Abstract

Very often deep level transient spectroscopy (DLTS) specimens deviate from ideal textbook examples, making the interpretation of spectra a huge challenge. This challenge introduces inaccurate estimates of emission signatures and the lack of appropriate estimates for the concentrations of the observed trap levels. In this work it is shown with the example of high-purity germanium that technology computer aided design including symbolic differentiation provides the necessary numerical stability over a wide temperature range to model DLTS spectra. Moreover high-purity germanium is a quasi intrinsic semiconductor for which it is well-known that original small signal theory can introduce strong errors. It is furthermore shown that the parasitic impact of fractional filling and high resistivity material can be modelled and that these modelled spectra can in the future assist the interpretation of experimental results.