Interaction of H, O2, and H2O with 3C-SiC surfaces

Infrared absorption spectroscopy studies of Si-dimer-terminated 3C-SiC(100) 3×2 and c4×2 surfaces reveal marked differences between their atomic scale reactivity with H, O2, and H2O and that of Si(100) surfaces. While atomic hydrogen is well known to passivate dangling bonds on all Si surfaces, H exposure on both 3C-SiC(100) 3×2 and c(4×2) surfaces induces a metallic state instead. Furthermore, hydrogenated 3C-SiC(100) 3×2 surfaces exposed to O2 clearly show that oxygen atoms are inserted below the top surface without any loss in the H coverage at room temperature. Finally, while H2O decomposes into H and OH on both Si(100) 2×1 and 3C-SiC(100) 3×2, subsequent atomic H exposure induces a metallic state on the latter only, creating a thin oxide strip on the top surface separated by a metallic trough.