Reduction of iron diffusion in silicon during the epitaxial growth of β-FeSi2 films by use of thin template buffer layers

Abstract

We fabricated continuous highly (110)/(101)-oriented β-FeSi2 films on Si (111) substrates by the facing-target sputtering method. An epitaxial thin β-FeSi2 template buffer layer preformed on the silicon substrate was found to be essential in the epitaxial growth of thick β-FeSi2 films. It was proved that the template reduced the iron diffusion into the silicon substrate during thick β-FeSi2 film fabrication. Even though the annealing was performed at high temperature (880 °C) for a long duration (10 h), iron diffusion was effectively hindered by the template. By introducing this template buffer layer, an abrupt interface without appreciable defects between the β-FeSi2 film and the silicon substrate formed. The mechanism for the reduction of iron diffusion by the template buffer layer is discussed.