MNOS Memory Related Effects of Oxygen Contamination in CVD Silicon Nitride

摘要

The effects of oxygen contamination on the memory-related characteristics of chemical-vapor-deposited (CVD) silicon nitride films are investigated. Oxygen was introduced in the gas phase during CVD, and the films are well characterized with regard to fractional concentrations of O, N, Si, and H. The effects of oxygen on the band gap, high field transport, and electrical alteration of accumulated charge are reported. Oxygen contamination strongly reduces the electrically-alterable charge accumulation in MNOS structures, and effective alteration is achieved only for approx. < 15 at.% oxygen when the nitride structure dominates in the oxynitride film. Oxygen has a small degradation effect upon charge retention even though it reduces high field transport. The oxygen contamination effect on electrical alteration is attributed to a band-gap related increase in barrier height to charge tunneling. (ERA citation 05:001488)