Is It Possible to Unambiguously Assess the Presence of Two Defects by Temperature-and Injection-Dependent Lifetime Spectroscopy?

This paper comprehends a systematic study of the prospects for an unambiguous assessment of the presence of two separate defects in silicon samples analyzed by temperature-and injection-dependent lifetime spectroscopy (LS). A large number of lifetime datasets are generated by simulating the presence of two defects and then fitted to a single-defect lifetime model. We have categorized the outcome in four categories: (i) a low overall fit quality and thus likely a combination of two defects, (ii) a high overall fit quality by dominance of one of the involved defect, (iii) a high overall fit quality because of symmetry effects in the model, and (iv) a high overall fit quality but no clear dominance by either involved defects nor presence of symmetry effects. We show that the presence of two defects can be ascertained through perceiving a low-quality fit to a single-defect model (category (i)), but we also show that a high-quality fit can arise from a combination of two defects (category (iv)). We show that in the case of categories (i) and (iv), it is possible to identify the two original defects through linear parameterization. In the case of (iii), however, the identification of two simultaneously occurring defects is highly ambitious and not practically feasible.