Structural features and surface composition of epitaxial α-FeSi₂ films obtained by CVD

Iron disilicide (α-FeSi₂) is one of the promising materials for building ohmic contacts over silicon substrates. Complex approaches have been used to synthesize this material resulting in the insufficient control of the film surface and interface structure. The morphology of the α-FeSi₂ films synthesized in this work by one-step CVD technique from ferrocene varies from the highly-oriented self-assembled crystallites to the dense film of α-FeSi₂. The orientation of the material could be changed from α-FeSi₂(001)||Si(100) to α-FeSi₂(111)||Si(100) by raising the deposition temperature from 900 to 1000 °C. The epitaxial relationships FeSi₂(001)||Si(100), α-FeSi₂(010)||Si(001), and α-FeSi₂(111)||Si(100), α-FeSi₂(11¯0)||Si(011) were determined for both orientations by a pole figure technique. It was found the surface of the material has an iron oxide admixture. Both the surface and interface structure might have a great impact on the properties of the α-FeSi₂/Si structures.