On the crystallographic characteristics of ion beam synthesised β–FeSi2

Nanometre-scale β–FeSi2 precipitates were introduced in a single crystal silicon substrate by low-dose ion-beam synthesis (IBS). The crystallographic relationship between these nanometre β precipitates and the silicon substrate has been studied by high resolution electron microscopy (HREM). The results show that the orientation relationship (OR) between the nanometre β precipitates and the silicon substrate is [100]β//[110]Si and (001)β//(111)Si, with abnormally large strain between the precipitates and the substrate. This OR is important for the formation of 90°-OD boundaries within β–FeSi2 grains. Also, the relationship between various reported low-index ORs has been analysed and a new low-index OR is predicted.