Fabrication of smooth beta-SiC surfaces by reactive ion etching using a graphite electrode

Reactive ion etching (RIE) of cubic beta-SiC in an SF6/O-2 plasma has been investigated using powered electrodes made from graphite and aluminum. With the graphite electrode the etched surfaces were smooth and shiny and had no column-like structures for any etching conditions while with the Al electrode the surfaces were dull and showed residues under the scanning electron microscope. This effect was observed with and without Al as the etch mask material. The etch rates of beta-SiC were investigated as functions of the SF6/O-2 ratio, the power, the pressure in the reactor chamber and the etching time. Up to a factor of two higher etch rates were obtained when the graphite electrode instead of the Al electrode was used. Since beta-SiC is deposited on Si the etch rates of Si and the SiC/Si etch rate ratio were investigated for different O-2 concentrations in the: plasma. (C) 1997 Published by Elsevier Science S.A.