Novel Single-Step Rapid Thermal Oxynitridation Technology for Forming Highly Reliable Electrically Erasable Programmable Read-Only Memory Tunnel Oxide Films

Abstract

We have proposed a novel single-step rapid thermal oxynitridation (SS-RTON) technology to obtain highly reliable ultrathin electrically erasable programmable read-only memory (EEPROM) tunnel oxide films. The SS-RTON process can be achieved by rapid switching of the ambient gases (O2→N2O) at the midpoint of the oxidation period, while maintaining the oxidation temperature. The results indicate almost no increase in the oxide-trap-assisted leakage and/or in the electron trap density, resulting in the increase of the charge-to-breakdown value. This behavior of the SS-RTON film can be explained by the idea that the trap sites are reduced by forming strong Si-N bonds in bulk SiO2.