A simple amorphisation-recrystallisation model for boron implanted iron films

A simple model of amorphisation of metallic layers by high dose metallaid ion implantation is derived. It is assumed that covalent bonds are necessary to stabilise the amorphous state. Therefore, only a small fraction of the region damaged by an implanted metalloid ion may remain amorphised. This gives rise to higher amorphisation doses for ion implantation in metals than in semiconductors. Thermal relaxation during implantation and subsequent annealing is considered. Based on this model it is possible to understand the influence of the implanted ion dose on the recrystallisation temperature. For boron implantation in iron the amorphised volume per ion and the activation energy of the recrystallisation process are calculated. It is suggested that amorphous Fe1-xBx alloys produced by rapid quenching or ion implantation are very similar for boron concentrations higher than x=0.18.