Exponentially strong leakage current increase in the proton-irradiated silicon nitride

Abstract

The charge transport in a strong electric field in proton-irradiated amorphous silicon nitride films with different irradiation doses is studied experimentally and theoretically. The leakage current increases with the increasing irradiation dose. The Frenkel model and the model of overlapping Coulomb potentials do not explain the charge transport mechanism. The charge transport mechanism in the initial Si₃N₄ film is explained by the Makram-Ebeid and Lannoo multiphonon isolated trap ionization model. The increase in the leakage current during irradiation is quantitatively described by the phonon-assisted tunneling of electrons between neighboring traps. Such a model explains the exponentially strong leakage current scatter in non-stoichiometric SiN_x films.