Effects of hydrogen on defect properties in germanium

Recent results on the effects of hydrogen on defects in germanium are reported. Two types of hydrogen-related defect states were observed. Undoped germanium crystals which were irradiated with 1.0 MeV electrons and subsequently implanted with 27 keV hydrogen exhibited two dominant electron traps at Ec-0.36 eV and Ec-0.41 eV. A divacancy-like defect associated with the level at Ec-0.41 eV becomes more stable when the defect captures hydrogen atoms. Sb-doped germanium crystals which were irradiated with 2.0 MeV electrons exhibited two dominant electron traps at Ec-0.23 eV and Ec-0.52 eV. Subsequent implantation with 25 keV hydrogen selectively passivated the 0.23 eV level associated with a defect containing antimony. The 0.23 eV level reduced by hydrogen implantation annealed out at 700C, much lower than the annealing temperature of the level produced by the electron irradiation alone. (author)