RAPID ANNEALING IN N-TYPE SILICON FOLLOWING PULSED 10 MEV ELECTRON IRRADIATION

The forward voltage Vf across a p+-n silicon diode, biased at constant current, was used to monitor the rapid annealing of damage introduced by a 5-μsec pulse of 10 MeV electrons. Silicon diodes (1N648) were irradiated at various temperatures from 90°to over 350°K. The large increase in Vf observed immediately after the irradiation pulse recovered partially to its preirradiation value in times varying from a few milliseconds at 300°K to a few hundred milliseconds at 100°K. The ratio of the change in Vf at 100 μsec after the irradiation pulse to the change after recovery had been completed varied from approximately three at 300°K to nearly seven at 100°K. The large degree of recovery indicates that defect annihilation is most likely responsible for the recovery process. The recovery kinetics of the rapid annealing are closely described by Waite's theory of diffusion-controlled annealing involving recombination of correlated and uncorrelated defects. Particularly for temperatures above 170°K, the initial stage of recovery proceeds at a rate proportional to (t)1/2 for nearly 50% of the annealing, as the theory predicts. The temperature dependence of the diffusion constant for this initial recovery is governed by an activation energy of approximately 0.12 eV. Comparison with other results indicates the possibility that diffusion of an interstitial into a divacancy, whereupon annihilation occurs, is responsible for the recovery mechanism. The low activation energy obtained is the result of the large injection of holes used in the measurements, that the injection level alters the charge state of the interstitial and recovery is enhanced. © 1969 The American Institute of Physics.