Simultaneous observation of SiO2 surface and SiO2/Si interface using self-assembled-monolayer island

Steps on SiO2 surface and in SiO2/Si interface, which remain on the surface after the formation of SiO2 on atomically flat Si(111) surface, are simultaneously observed with a novel use of self-assembled-monolayer (SAM) islands. After the formation of octadecyltrichlorosilane (OTS) SAM islands on SiO2, SiO2 layers in the area which are not covered by OTS-SAM are completely removed by hydrofluoric acid (HF) to expose SiO2/Si interface, followed by atomic-force-microscopy (AFM) observation. OTS-SAM islands trace the morphology of SiO2 surface underneath, whose structure is preserved even after being dipped into HF. The results indicate that the steps on SiO2 and in the interface of SiO2/Si show no lateral shift, which suggests no step-flow during oxidation for stress relief.