MNOS Memory Technology With Oxynitride Thin Films

Abstract

Memory properties of a metal-oxynitride-oxide-silicon (MNOS) device were investigated as a function of amount of oxygen and hydrogen impurities in the oxynitride films. The retention and endurance device characteristics improved by 60% and 10/sup 7/ to 10/sup 8/ cycles, respectively, as 13% oxygen was introduced in the oxynitride film. The interface state density decreased from 5.1 to 3.65/spl times/10/sup 11/ cm/sup -2/ eV/sup -1/, with an increase of approximately 21% oxygen in the oxynitride film, and further decreased to 2.1/spl times/10/sup 11/ cm/sup 2/ eV6/sup -1/ after hydrogen annealing. The results indicate that the nonvolatile memory properties of MNOS devices can be altered and considerably improved by incorporating oxygen in the oxynitride film and selecting appropriate processing and annealing conditions. >