Fabrication of highly oriented β-FeSi2 by ion beam sputter deposition

We have prepared the 'environmentally friendly' semiconductor, β-FeSi2 thin films by ion beam sputter deposition method. The temperature of Si (100) substrate during the deposition and total amount of deposited Fe have been changed in order to find the optimum condition of the film formation. The crystallinity and surface morphology of the formed silicides were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. It is understood that the domain of the epitaxially grown β-FeSi2 increases with the substrate temperature up to 700degC at the fixed amount of deposited Fe (33 nm) by XRD spectra. On the other hand, α-FeSi2 is appeared and increased with the temperature above 700degC. Granulation of the surface is also observed by SEM images at this temperature region. At the fixed temperature condition (700degC), formation of α phase, which is obtained at the higher temperature compared with β phase, is observed for the fewer deposited samples. These results suggest the possibility of the epitaxially grown β-FeSi2 formation at the lower (< 700degC) temperature region. (author)