On the role of interface states in low-voltage leakage currents of metal–oxide–semiconductor structures

This work investigates the additional gate current component with respect to the direct tunneling of electrons between the conduction bands measured in ultrathin oxide metal–oxide–semiconductor field-effect transistors at low voltages, before and after the application of a high field stress. We discuss several possible conduction mechanisms on the basis of the band diagram profiles obtained by means of a one-dimensional self-consistent Poisson–Schrodinger solver and we explain why this additional leakage current is mainly due to electron tunneling involving the native and stress-induced interface states in the silicon band gap either at the cathode or at the anode.