Radiation Annealing and Modification of the 35° and 65°K Defects in Germanium at Low Temperature

Damage introduced in n-type germanium at ∼7°K with 1.0 MeV electrons undergoes radiation annealing and conversion when subjected to 0.5 MeV electron irradiation at ∼7°K. The radiation annealing with only 65°K and permanent defects present appears to be a first-order process with an estimated cross section of 10−15 cm2, while radiation annealing with 35°, 65°K, and permanent defects present appears to be a second-order process. It appears that only the 35° and 65°K defects are recovered and 65°K defects are converted to 35°K defects as part of the radiation-annealing process. The radiation anneal of converted damage seems to be the rate-limiting process in the radiation anneal of 65°K defects. Our results show evidence for another type of 65°K defect as suggested by Zizine and by Whan's work. If this is the case, then our results imply that this second type is not subject to radiation annealing.