Analysing defects in silicon by temperature- and injection-dependent lifetime spectroscopy (T-IDLS)

To demonstrate the full potential of temperature- and injection-dependent lifetime spectroscopy (T-IDLS) as a method to characterise defects in silicon, measurements on an intentionally tungsten-contaminated wafer were performed at different temperatures up to 151 °C. By determination of the recently introduced defect parameter solution surface (DPSS) the detailed analysis revealed two discrete solutions regarding a deep defect level. Due to high accuracy of the measurements and due to a temperature range that allowed the turnover from increasing to decreasing lifetime to be observed, identification of a unique solution of the defect parameters has been achieved. These findings precisely confirm recent predictions in a theoretical study. Thus, the energy level and band gap half of the underlying deep defect related to tungsten could be determined unambiguously: E(ind t)-E(ind V)=0.34±0.02 eV with a corresponding ratio of capture cross-section asymmetry k=sigma(ind n)/sigma(ind p)=9.6±4. An investigation of the temperature dependence of the minority carrier capture cross-section identified the multiphonon emission capture as the relevant mechanism underlying recombination. The activation energy is determined as E?=0.017±0.003 eV.