Optical and electrical characterization of β-FeSi2 epitaxial thin films on silicon substrates

Abstract

Electrical measurements have been carried out on epitaxial FeSi2 layers on silicon substrates, the silicide thickness being either 180 or 350 Å. A direct gap of 0.85 eV was measured by optical absorption. Current-voltage characteristics of mesa-structures Cr/Fe/FeSi2/Si show a p-type semiconductor behavior. Capacitance-voltage and capacitance-temperature data at different frequencies indicate a large response of deep levels or interface states. Admittance spectroscopy yields the activation energy and capture cross section of two levels. Finally an energy-band diagram is proposed.