A THEORETICAL-MODEL FOR THE DENSITY DISTRIBUTION OF MOBILE IONS IN THE OXIDE OF METAL-OXIDE-SEMICONDUCTOR STRUCTURES

A theoretical model for the density distribution of the mobile ions in the oxide of a metal-oxide-semiconductor structure is developed. It is based on the concept that at any point in the oxide the equilibrium concentration of these mobile ions is attained when the combined mobilizing forces, namely, thermal diffusion, internal, and external electric fields, become just sufficient to provide necessary activation energy to the ions to surmount the effective potential well. All these forces, acting on a single ion, have been obtained independent of each other and then combined to yield the equilibrium density distribution of the mobile ions. The results of the present model are consistent and in good agreement with earlier experimental results.