Oxidation of partially Ga‐terminated Si(111) surfaces with clean 7×7 striped areas along atomic step edges was investigated using scanning reflection electron microscopy. Molecular oxygen exposure of 100 L at the substrate temperatures of 410 °C oxidized Ga atoms on the Ga‐terminated areas as well as Si atoms on the clean 7×7 areas. The Ga oxides were selectively desorbed over the Si oxides during annealing. This results in the formation of stripe‐patterned Si oxides on the surface. After growth of an 8‐monolayer Si film and subsequent annealing, Si grooves with a depth of about 1 nm and a width around 200 nm were formed along the step edges by excess Si‐assisted thermal desorption of the Si oxides. ©1996 American Institute of Physics.