Fluorine in Ge: Segregation and EOR-defects stabilization

In this paper we investigate the F behavior in Ge during solid phase epitaxy (SPE) and post-SPE annealing. Fluorine implanted with a fluence of 1 × 1015 F/cm2 and an energy of 35 keV induced the formation of an amorphous Ge layer. Detailed chemical and structural characterizations of the as implanted and annealed samples evidenced a strong segregation of F at the moving amorphous/crystalline interface, leading to a remarkable SPE rate retardation. In addition, we observed that F accumulates in correspondence of the end of range (EOR) defects. The comparison between the thermal evolution of damage produced by self-implantation and F implantation in Ge suggests that F increases significantly the stability of EOR. Such behavior clarifies the role of F in modifying the As diffusion in Ge recently reported in literature.