DRY-ETCHING OF UNDOPED AND BORON-DOPED POLYCRYSTALLINE DIAMOND FILMS

This paper describes etching of polycrystalline diamond films by reactive ion etching (RIE) in an O-2 plasma. The RIE patterned films showed anisotropic etching profiles. During RIE, columnar structures were created on the etched surface., Changes in r.f. power and total pressure had no influence on the formation of columns, nor had changes in film resistivities due to different diborane concentrations during him deposition. However, if SF6 was added to the O-2 plasma the formation of columns could be suppressed. In this case the silicon substrate was also attacked. X-ray photoelectron spectroscopy analysis of a film etched in O-2 showed that aluminum and fluorine from the reactor walls deposited onto the film during etching could play a role in the formation of the columns.