Plasma processed ultra-thin SiO sub(2) interfaces for advanced silicon NMOS and PMOS devices: Applications to Si-oxide/Si oxynitride, Si-oxide/Si nitride and Si-oxide/transition metal oxide stacked gate dielectrics

The substitution of alternative gate dielectrics for thermally-grown SiO sub(2) and nitrided SiO sub(2) in aggressively scaled devices requires a significant processing change in going from thermally-grown to deposited dielectrics. This requires separate and independent steps for (i) the formation of Si-dielectric interface and (ii) the deposition of the dielectric thin film, which can be (a) Si nitride, or a Si oxynitride alloy, or (b) a high-k oxide. It is demonstrated that ultra-thin, nitrided Si-SiO sub(2) interface layers prepared by 300 degree C remote plasma processing can be effective in insulating device performance and reliability from deleterious effects associated direct deposition of alternative dielectric materials directly on to hydrogen-terminated Si surfaces. These interfaces perform equally well with Si nitride, Si oxynitride and high-k oxides, and contribute approximately 0.3-0.4 nm to the overall electrical oxide thickness (EOT), limiting aggressive scaling of EOT to approximately 0.6 nm.