Quantitative physicochemical modelling was applied to the thermal annealing of high dielectric constant thin films on Si in O and/or an inert ambient. In particular, the kinetics of SiO2 interfacial layer growth at the high-k material structure/Si interface were studied. Upon annealing, the transport of O species in the high-k film to the Si interface was quantitatively evaluated. One-dimensional unsteady-state diffusion-reaction equations were used to model the time evolution of the interfacial SiO2 layer thickness. Because of the continuously increasing interfacial SiO2 layer, the proposed model incorporated the moving interface that alters the diffusion length of the O species. The numerical solution of the resulting modelling equations was based on the finite volume analysis method and it results in SiO2 thickness profiles that comprise an early fast growth stage followed by pseudosaturation into a self-limited regime. The model predictions were found to agree satisfactorily with published experimental results. The use of alumina as a potential O diffusion barrier was also studied. Alumina was predicted to be an efficient barrier to O diffusion, in agreement with published experimental data.

Diffusion-Reaction Modeling of Silicon Oxide Interlayer Growth during Thermal Annealing of High Dielectric Constant Materials on Silicon. D.Gopireddy, C.G.Takoudis: Physical Review B, 2008, 77[20], 205304 (9pp)