Oxygen etching of the Si(100)-(2 × 1) surface

We used scanning tunneling microscopy (STM) to study the etching behavior of Si(100)-(2 × 1) by oxygen at pressures in the 10−8 Torr range and at temperatures between 600 and 700°C. In this regime of pressure and temperature, we only observed step etching caused by the migration of dimer vacancies to the step edges. On the terraces, narrow line vacancies perpendicular to the dimer rows were observed similar to the line vacancies caused by sputtering and annealing previously reported.