Effects of Dosage and Impurities on Radiation Damage of Carrier Life Time in Si

To clarify several points mentioned in our previous report, radiation damage and its annealing process in various kinds of Si crystals were investigated by measuring the change in minority carrier life time with microwave absorption method. (i) Both irradiation dose rate and total dose have a remarkable effect on annealing behavior of carrier life time. For example annealing temperature increases remarkably with increasing total dose of irradiation. These behaviors are also found in the annealing of A-center measured by Hall effect, which have been published elsewhere. (ii) The radiation damage and annealing process of life time were found to be very sensitive to the impurities such as oxygen, Fe, Ni and Cu. (iii) The depth of the recombination and trap levels and their cross sections were estimated from temperature dependences of life time and of thermal release time in various kinds of Si crystals.