Fast and Slow Quenching Defects in Germanium

Fast quenching defects are observed in germanium samples from crystals grown in hydrogen atmospheres, but not if the hydrogen has been removed by out-diffusion or in material crystallized in a nitrogen atmosphere. The effective diffusion coefficient for hydrogen in Ge at 430°C was found to be 1.8 × 10-8cm2/sec. Energy levels and concentrations of slow quenching defects have been studied by Hall effect vs. T measurements as a function of annealing time at 430°C. In addition to the 0.08 eV acceptor commonly seen in dislocation-free samples, several other defects appear with energy levels closer to the valence band. The concentrations of all these defects increase initially and then disappear again with further annealing.