Structural and trap properties of polycrystalline semiconducting FeSi2 thin films

The structural and trap properties of polycrystalline beta-FeSi2 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 gamma > 1) behaviour and is proportional to I-beta (with beta < 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 beta-FeSi2 thin films are discussed in terms of the annealing method and the annealing conditions.