BEHAVIOR OF POINT RADIATION DEFECTS DURING RAPID PHOTON ANNEALING OF GAAS-LAYERS IMPLANTED WITH VARIOUS DOSES OF SI AND SE IONS

The formation and relaxation of point radiation defects during anneali ng of GaAs wafers implanted by Si and Se ions with doses below or abov e the amorphization dose were studied using X-ray diffractometry, TEM and SIMS. Annealing involves different processes in wafers implanted w ith high and low doses. High-dose implantation generates dislocation l oops that further transform to dislocation networks. ?The dislocation structures depend on the type of implanted ions. Low-dose implantation avoids the formation of dislocation loops. The physical surface plays a significant role in the relaxation of radiation defects, especially after low-dose implantation. In this latter case, vacancies and inter stitial atoms are spatially separated. Interstitial atoms migrate to t he surface due to their higher mobility and, hence, a vacancy-rich sup erficial layer forms.