Fast silicon etching using an expanding cascade arc plasma in a SF6/argon mixture

An expanding cascaded arc is used as a fluorine atom source for fast etching of silicon. Extremely high etch rates up to 1.3 μm/s have been obtained. A reactor parameter study has been performed. The obtained selectivity Si/SiO2 is ∼11 for substrate temperatures of 600 °C, increasing to ∼20 at 100 °C. The etching proces is fully isotropic.