Experimental study on the thermal evolution of silicon defects with zonal characteristics induced by precisely localized irradiation of focused helium ion beams

The thermal evolution of defects introduced in silicon by line scanning with helium ion microscopy was investigated, confirming that the evolution of the defective structure after annealing at 650 degrees C for 1 h results in a central void channel and a sector ring of cavities surrounding it, located in the amorphous and transition regions of the unannealed pre-irradiated sample, respectively. The variation of defective structures with annealing temperature and ion dose indicates that high temperature is favorable for the formation of void channels and cavities, and the coarsening and recrystallization processes compete in the shaping of a void channel. The total volume of the defective structure is linearly related to the ion dose, while the zoning phenomenon is attributed to the differences in the vacancy amounts within their locations. These results provide direct experimental evidence for the thermal evolution of defects with zonal characteristics induced by precisely localized helium irradiation.