Solid-Phase Growth of β-FeSi_2 on Si Substrates with Different Crystal Orientations

Orientation dependent solid-phase growth of /3-FeSi2 thin films on (100), (110), and (111) Si substrates has been investigated by using a-Fe(thickness: 20 nm)/c-Si stacked structures. XRD measurements suggested that the substrate orientation dependence of the formation rate of /3-FeSi2 was as follows: (100) > (111) > (110). This dependence can be explained on the basis of the lattice mismatch between /3-FeSi2 and Si substrates, i.e., the lattice mismatch between 13-FeSi2 (100) and Si (100), / -FeSi2 (110) or (101) and Si (111), and 13-FeSi2 (010) or (001) and Si (110) are 1.4-2.0%, 5.3-5.5%, and 9.2%, respectively. The substrate orientation dependence of solid-phase growth becomes relatively remarkable for very thin films.