Structural and trap properties of polycrystalline semiconducting FeSi₂thin films

Abstract

The structural and trap properties of polycrystalline β-FeSi 2 thin films, grown by rapid thermal or conventional furnace annealing on (100) Si substrates of high resistivity, were investigated by transmission electron microscopy and low-frequency noise measurements performed at room temperature with the current I as a parameter. The power spectral density of the current fluctuations shows a 1/f (with γ > 1) behaviour and is proportional to I β (with β < 2). Based on an analytical model for the spectral current density, the trap density at the Fermi level has been determined using the experimental data of Hall measurements. The structural properties and the trap density of the β-FeSi 2 thin films are discussed in terms of the annealing method and the annealing conditions.

Structural and optical analysis ofβ−FeSi2thin layers prepared by ion-beam synthesis and solid-state reaction

“…These values are in good agreement with the Hall mobilities reported for IB synthesized samples 1 and for polycrystalline ␤-FeSi 2 layers prepared by solid phase epitaxy. 12,31 The low values of the carrier mobility in polycrystalline films, reported so far, are usually related to a large scattering from the films imperfections. 4,32 On the other hand, according to Christensen 17 there are reasons to believe that ␤-FeSi 2 is characterized by an unusually strong electron-phonon scattering in the band-edge states.…”