Low temperature epitaxial growth of Fe₃Si on Si(111) substrate through ultra-thin SiO₂ films

Growth of ferromagnetic silicide Fe₃Si on SiO₂ was investigated by using the molecular beam deposition technique. Measurements combined with X-ray diffraction and reflective high-energy electron diffraction clearly indicated that poly-crystal Fe₃Si layers were formed on Si(111) substrates covered with thick (> 2.7 nm) SiO₂ films. On the other hand, it is suggested that Fe₃Si layers were epitaxially grown on Si(111) substrates covered with ultra-thin (1.3 nm) SiO₂ films. Transmission electron microscopy and electron diffraction measurements confirmed that single crystalline Fe₃Si layers with (111) orientation were formed on Si(111) substrates with ultra-thin (1.3 nm) SiO₂ films. These results were considered to originate from heteroepitaxy on crystalline ultra-thin SiO₂ layer or lateral epitaxial growth over SiO₂ through pinholes.