Trap-Assisted Tunneling Hole Injection in SiO2: Experiment and Theory

The injection of holes from silicon through silicon oxide (SiO2) in a tantalum nitride-aluminum oxide-silicon nitride-silicon oxide-silicon (TANOS) structure has been studied experimentally. Using the high-permittivity Al2O3 insulator as a blocking one suppresses the parasitic injection of electrons from the conducting TaN contact. This allows the injection of holes from the substrate into nitride to be studied up to comparatively high electric fields. The experimental data are not described by the standard Fowler-Nordheim law with reasonable physical parameters. At the same time, these data are in good agreement with the model of trap-assisted tunneling hole injection in SiO2. The developed theory shows that the traps in a narrow energy band make a major contribution to this process, i.e., this injection is resonant in nature.