RELATIONSHIP BETWEEN NITROGEN PROFILE AND RELIABILITY OF HEAVILY OXYNITRIDED TUNNEL BRIDE FILMS FOR FLASH ELECTRICALLY ERASABLE AND PROGRAMMABLE ROMS

A larger charge-to-breakdown value and much less threshold-voltage narrowing in the endurance properties of flash electrically erasable and programmable ROMs were achieved by incorporating a greater amount of nitrogen (similar to 10(21) atoms/cm(3)) into the bulk of thin oxide films, as well as near the oxide/Si interface. The charge to breakdown value of thin oxide films formed under an optimized heavy oxynitride condition (dry oxidation at 1100 degrees C; NH3 annealing at 1000 degrees C for 30 s; N2O annealing at 1100 degrees C for 30 s) was four times as large as that of a conventional dry oxide film. These results were attributed to the suppression of stress-induced charge traps and the interface state, due to the introduction of nitrogen atoms in the oxide bulk, as well as at the oxide/Si interface.