Modeling of the Leakage Current in Ultrathin La2O3 Films Using a Generalized Power Law Equation

Abstract

The leakage current in electrically stressed MOS structures with ultrathin lanthanum oxide (La2O3) films was investigated. The samples were obtained by the electron-beam evaporation technique and annealed in-situ in ultra-high vacuum conditions. We show that the application of successive voltage ramps leads to a set of current-voltage (I-V) characteristics that can be simulated using a power-law model with series and parallel resistances. This particular voltage dependence, in combination with the stepwise increase exhibited by the current-time (I-t) characteristic during a constant voltage stress, suggests that the leakage current through the oxide layer might be ascribed to multiple dielectric breakdown conduction