Laser annealing of point defects in silicon and gallium arsenide

The efficiency of laser annealing of point defects introduced into Si and GaAs by electron bombardment at the energy of 3.5 MeV is studied. The change of the concentration of the point defects in the crystals is judged by measurements of electric conductivity, the Hall effect and volt-farad characteristics of the Schottky barriers. It is established that with the decrease of laser pulse duration the defect annealing temperature increases. At laser pulse duration of the order of 107-108 sec the total annealing of the point defects has hot been observed even if the calculation temperature of the laser irradiated layer is greater than the melting temperature (Tsub(m)). The annealing kinetics depending on time of thermal processing is analyzed. The results of calculation are in good agreement with the experimental data. In particular, annealing of E-centres in Si at temperatures of T10-6 sec. The necessity of additional nanosecond annealing of implanted layers by millisecond pulses or continuous heating to eliminate point defects in weakly disordered regions of the target