Effect of surface treatment of Si substrate on the crystal structure of FeSi_2 thin film formed by ion beam sputter deposition method

摘要

Ion beam sputter deposition method under ultra-high vacuum conditions was employed to form β-FeSi_2 thin films on Si(100) substrate. We investigated the effect of three different kinds of surface treatment of Si on the crystal structure of FeSi_2 film, which was characterized by means of X-ray diffraction analysis and transmission electron microscopy (TEM) observation. The films formed on a substrate treated by thermal etching (TE) consisted of β-FeSi_2 with various crystal orientations. The films formed with sputter etching (SE) and wet etching methods also consisted of β-FeSi_2, but with comparatively strong (100) preferential orientation. From TEM observations, the films formed with TE method were composed of coalesced β-FeSi_2 islands, whereas those formed with SE method were almost continuous.