Structural and electrical properties of β-FeSi2 polycrystalline films with low electron density

The structural and electrical properties of β-FeSi2 polycrystalline films grown by RF magnetron sputtering were investigated. In the optimization of growth conditions, single-phase β-FeSi2 films were reproducibly grown when the initial rate of temperature increase (T r) to 800 °C for silicidation reaction was set at T r = 1 min. Undoped β-FeSi2 films showed an n-type conduction with a low electron density of ~2 × 1016 cm−3 and a high electron mobility of ~800 cm2 V−1 s−1 at room temperature. In the temperature dependence of electrical properties in the β-FeSi2 films, a change of the conduction mechanism from a band conduction to a localized conduction was observed. The transition temperature was systematically reduced by increasing the annealing time at 800 °C.