Independent interface and bulk film contributions to reduction of tunneling currents in stacked oxidernitride gate dielectrics with monolayer nitrided interfaces

Direct tunneling limits aggressive scaling of thermally-grown oxides to about ;1.6 nm, a thickness at which the tunneling current at 1 V is ;1 Arcm2. This paper presents experimental results, supported by interface characterizations and model calculations, which demonstrate that multi-layer or stacked gate dielectrics prepared by remote plasma processing comprised of i. ultra-thin nitrided SiO2 interface layers, and ii. either silicon nitride or oxynitride bulk dielectric films, can extend the oxide-equivalent thickness, tox-eq, limit down to ;1.1–1.0 nm. A similar stacked gate dielectric, which substitutes higher-k oxides such as Zr Hf.O2–SiO2‘silicate’ alloys or Ta2O5for the nitrides or oxynitride alloys, is projected to further reduce tox-eq to ;0.6–0.7 nm. q2000 Published by Elsevier Science B.V.