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

Direct tunneling Limits aggressive scaling of thermally-grown oxides to about similar to 1.6 nm, a thickness at which the tunneling current at 1 V is similar to 1 A/cm(2). 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, t(ox-eq), limit down to similar to 1.1-1.0 nm. A similar stacked gate dieletric , which substitutes higher-k oxides such as Zr(Hf)O-2-SiO2 'silicate' alloys or Ta2O5 for the nitrides or oxynitride alloys, is projected to further reduce t(ox-eq) to similar to 0.6-0.7 nm. (C) 2000 Published by Elsevier Science B.V.