SURFACE-STRUCTURE OF BETA-FESI(2)(101) EPITAXIALLY GROWN ON SI(111)

The surface morphology and structure of beta-FeSi2(101) films epitaxia lly grown on Si(111) has been studied by means of Scanning Tunneling M icroscopy (STM). The films are formed by large crystallites which are single domain. Each crystallite has only one of the three possible azi muthal orientations with respect to the substrate. A large density of planar defects, however, is detected on top of each crystallite. They are assigned to intrinsic stacking faults and their existence seems ha rd to avoid. This high density of intrinsic defects casts serious doub ts on the use of beta-FeSi2 as an optoelectronic material.