Majority carrier capture rates for transition metal impurities in germanium

The carrier capture cross-sections of deep levels in semiconductors are important parameters determining the properties of devices. Therefore not only the electrical levels of the transition metal impurities in germanium have been identified with DLTS but also the capture cross-sections have been directly determined by means of the DLTS amplitude as a function of the DLTS filling pulse duration. Due to the accurate fitting method the temperature dependence of these cross-sections could be measured. For the electron traps the empirical rule for phonon-assisted capture was observed, while for the hole traps a cross-section inversely proportional to the temperature was measured. Comparing the observed values it might be predicted that Ni and Co are the most efficient lifetime killers in p-type germanium, while Cr and Hf are the least efficient.