AFM surface imaging of thermally oxidized hydrogenated crystalline silicon

This work presents atomic force microscopy (AFM) results on surface imaging of ultrathin SiO2 oxides with thickness ∼10 nm. The SiO2 was grown by 850 °C dry oxidation of (1 0 0)Si substrates which underwent RCA wet and dry hydrogen plasma procedures prior to oxidation. The pre-oxidation cleans lead to significantly smooth Si surfaces, but on the hydrogenated silicon surfaces formation of hillocks is observed. Oxidation of silicon, although yielding a smooth outer oxide surface, enhances generation of hillocks. The biggest roughness and the most nonuniform distribution of hillocks are obtained on oxides formed on silicon treated in plasma at 300 °C.