BEHAVIOR OF RADIATION-INDUCED DEFECTS AND AMORPHIZATION IN SILICON CRYSTAL

We have investigated the dose rate dependence of the lateral amorphiza tion of silicon crystals irradiated with 40 keV Si2+ focused ion beams (FIB) as a function of sample temperature. The recovery time of point defects, tau, and the extent of their distribution, d, around the col lision cascades produced by impinging ions were evaluated. The amorpho us line-width was measured with scanning electron microscopy (SEM) aft er a selective etching. We have obtained a critical dose rate 1/(tau d (2)) of 1.0 x 10(15) cm(-2)s(-1) for radiation at 100 degrees C. The t emperature dependence of the critical dose rate suggests that the late ral amorphization is controlled by a simple kinetics of the defects wi th an activation energy of 0.85 eV. From the value of the activation e nergy, we speculate that the recovery process of radiation-induced def ects is controlled by the migration of interstitial Si atoms.