Extending storage dielectric scaling limit by reoxidizing nitrided NO dielectric for trench DRAM

Conventional nitride/oxide (NO)-based storage dielectric has been demonstrated to possess the capability to extend its employment in trench dynamic random access memory (DRAM) by additional NH₃ nitridation and in situ N₂O reoxidation. Through this technique, cell capacitance could be enhanced by 12.2% as compared with NO dielectric while preserving tunneling current below 1 fA/cell. Even with NH₃ nitridation and consequent well-known introduction of electron traps, the great improvement in tunneling leakage and reliability are exhibited after N₂O treatment. With prominent electrical properties, this technique proves its eligibility for next-generation DRAM before the maturity of introduction of high-κ material into production.