Fundamental phenomena in heteroepitaxial growth studied by scanning tunneling microscopy

Abstract

We have used scanning tunneling microscopy to study the heteroepitaxial growth of transition metal silicides on Si by molecular beam epitaxy, in particular the temperature-induced phase transition from pseudomorphic FeSi 2 to β-FeSi 2/Si(111). Prior to the transformation the cubic silicide films become laterally inhomogeneous which can be explained by a local distortion towards the orthorhombic β-FeSi 2 phase. On stoichiometrically grown samples β-FeSi 2 nucleates in a (101)-orientation as in solid phase epitaxy. From slightly Fe-rich initial deposits high-quality epitaxial β-FeSi 2 with a (001)-orientation and a grain size of several μm could be grown. The elastic strain is relaxed by a dense array of buried misfit dislocations.