Nanometer-scale Si selective growth was performed on Au-adsorbed Si(111) windows in ultrathin (0.3 nm thick) silicon-dioxide (SiO2) films. Nanometer-scale Au-adsorbed Si(111)-5x2 terraces grew from the step edge of Si(111)-7x7 terraces. Thermal oxidation of the partially Au-adsorbed Si(111) terraces was done in an atmosphere of molecular oxygen. Selective thermal oxidation was investigated under various oxidation conditions; Si(111)-7x7 terraces were oxidized while the Au-adsorbed Si(111) terraces remained. Si crystals were selectively grown on the Au-adsorbed Si(111), while Au atoms were always on the top layer of the grown crystals. On a vicinal Si(111) surface misoriented toward the [(11) over bar 2] direction, the grown Si crystals along the step edges were 20 nm wide, 500 nm long, and 4 nm high.