RDE法によるSi/β-FeSi_2/Si(001)構造の作製(<小特集>ヘテロエピタキシーと界面構造制御)

抄録

Semiconductingβ-FeSi_2 having a direct band gap of about 0.85 eV at room temperature has attracted considerable attention because it can be grown epitaxially on Si substrates. In this article, we present firstly the epitaxial growth ofβ-FeSi_2 layers on Si (001) substrates by reactive deposition epitaxy (RDE; deposition of Fe on a hot Si substrate). Then, aggregation of monocrystallineβ-FeSi_2 by annealing and by Si overlayer growth is presented. A β-FeSi_2 film on Si (001) aggregated into islands after annealing at 850℃ for 1 hour in ultrahigh vacuum (UHV). The β-FeSi_2 islands aggregated further into a spherical shape in Si crystals when a 1-μm-thick Si overlayer was grown epitaxially at 750℃ by molecular beam epitaxy (MBE). Cross-sectional transimission microscope (XTEM) observation revealed that the epitaxial relationship between the two materials and monocrystalline nature were revealed after the annealing and the Si overgrowth.