Effects of Hydrogen or Nitrogen on Growth of Oxygen-Related Defects in Germanium

Oxygen-doped germanium crystals were used to demonstrate the interaction between implanted hydrogen or nitrogen atoms and the oxygen-related defects. The electron trap at Eo-0.26eV associated with the germanium A-center was found to be formed by electron irradiation. Another level at Eo-0.21eV also was observed on annealing at 120 °C. As for the sample implanted with hydrogen ions following electron irradiation, the trap concentration is four times as large as that for electron irradiation alone. It is probable that the germanium A-centers produced by electron irradiation capture hydrogen atoms and increase electrically active centers. After nitrogen implantation following electron irradiation, the Eo-0.26eV level almost annealed out at 140 °C and the trap at Eo-0.21eV wasn't observed. We propose that the reduction in the oxygen-related defect growth is due to the prevention of defect migration with nitrogen atoms.