Photolytic Etching of Polycrystalline Silicon in SF6 Atmosphere

Photolytic etching of polycrystalline silicon has been investigated in an SF6 atmosphere. SF6 molecules were excited by one-photon absorption under D2 lamp irradiation. This reaction was found to have high reaction-efficiency, 130 nm/Jcm-2. The distribution of the etch rate in the sample was remarkably influenced by the gas flow. This reaction was thus caused by photo-excitation of SF6 molecules in atmosphere, and not by that of absorbed SF6 molecules over a polycrystalline silicon surface.