DEPTH OF DEFECT ANNIHILATION IN SILICON BY PULSE LASER ANNEALING - EXPERIMENT AND THEORY

Defect annihilation has been observed in silicon as a result of laser annealing using a Q-switched ruby laser. The threshold pulse energy density for defect annihilation was found to be 1 J/cm2 (pulse length ∼25 ns), and the depth of the defect-free region was found to increase with increasing pulse energy. A thermal model was developed which predicts the depth of melting and the recrystallization velocity. The calculated depth of melting was found to be in good agreement with the experimentally determined depth of defect annihilation. The defect annihilation occurs as a direct result of the extremely high recrystallization velocities which are associated with laser annealing with short pulses.