Defect characterization by temperature and injection-dependent lifetime spectroscopy

A new defect characterization technique, temperature and injection-dependent lifetime spectroscopy (TIDLS), is introduced. Injection-level dependent lifetime curves are measured at various temperatures by means of the contactless quasi-steady-state photoconductance (QSSPC) technique. The semiconductor sample is placed on top of a temperature-controlled stage, kept at a short distance from the photoconductance-sensor coil in the rf bridge circuit. The experimental applicability of the TIDLS is demonstrated on an Al-doped Czochralski silicon sample, containing a specific Al-related defect species. It is shown that, compared to previous lifetime spectroscopy techniques, the TlDLS not only determines the defect energy level with improved accuracy, but is also capable of determining the temperature dependence of the capture cross sections. Moreover, the method permits the separation between shallow and deep-level centers.