Sputter etching effect of the substrate on the microstructure of β-FeSi2 thin film prepared by ion beam sputter deposition method

Beta iron disilicide (β-FeSi2) is one of the candidate materials for a compound semiconductor, which is promising for optoelectronic devices. β-FeSi2 film has been obtained by ion beam sputter deposition (IBSD) on Si(1 0 0) substrates that are pre-treated by sputter etching by Ne+. In the present study, the sputter etching effect on the substrate was investigated through the cross-sectional observation of transmission electron microscopy (TEM) in order to find the conditions for fabricating uniform β-FeSi2 films which have high orientation and form a smooth interface with the substrate. Nanostructural changes of the deposited film and the interface were observed as a function of sputter Ne+ energy and fluence. It was found from the observed crystal structure of the films and interface that the effect of the surface pre-treatment significantly changes with the ion energy and fluence. By 1 keV irradiation at the fluence of 3 × 1016 ions/cm2, β-FeSi2 film was epitaxially grown on Si(1 0 0) substrate with an atomically smooth interface.