Effects of Silicon-Nitride Films on the Electronic Properties of Si-SiO_2 Interfaces

The electronic properties of Si-SiO_2 interface states in Metal-Nitride-Oxide-Silicon (MNOS) with thick oxide films are investigated. It is shown that a large number of acceptor-like interface states are created when MNOS is annealed at high temperatures, and that subsequent low temperature hydrogen annealing reduces the number of these states. We found that the energy distribution of true interface states is independent of their density. The possible cause of these interface states may be thermal stress induced at the interface.