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. (C) 2002 American Institute of Physics.