Gate quality ultrathin (2.5 nm) PECVD deposited oxynitride and nitrided oxide dielectrics

Ultrathin oxynitride using plasma assisted deposition was evaluated against thermal oxide and nitrided thermal oxide as an alternative direct tunneling gate dielectric to thermal oxide in the 2.5-nm regime. The oxynitride showed an enhanced high field effective mobility relative to the thermal oxide although the low field mobility was slightly depressed. The N/sub 2/O nitrided oxide showed an enhanced high field effective mobility with no degradation in low field mobility. The interface state density of the oxynitride was equivalent to that of the thermal and nitrided thermal oxides; a very welcome observation for this deposition chemistry and anneal conditions.