A comparison between silicon oxynitride and high-k films on silicon regarding thermally driven atomic transport is presented. Emphasis is given to the behavior of these structures upon annealing in O_2. The experimental approach is to combine isotopic substitution preparation techniques and nuclide-specific characterization methods. We observe remarkably different atomic transport phenomena. Upon annealing in Ot, silicon oxynitrides exchange most of the original oxygen at the film surface and part of the nitrogen; silicon oxide growth is observed below the original oxynitride/silicon interface. As a general rule, high-k materials do not exchange as much oxygen at the surface, but the exchange occurs throughout the whole film thickness. Oxygen diffusion is faster than in oxynitrides, and transport of silicon from the substrate or in the films is observed in specific cases.
展开▼
