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

This paper describes etching of polycrystalline diamond films by react ive ion etching (RIE) in an O-2 plasma. The RIE patterned films showed anisotropic etching profiles. During RIE, columnar structures were cr eated 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 dep osition. However, if SF6 was added to the O-2 plasma the formation of columns could be suppressed. In this case the silicon substrate was al so attacked. X-ray photoelectron spectroscopy analysis of a film etche d in O-2 showed that aluminum and fluorine from the reactor walls depo sited onto the film during etching could play a role in the formation of the columns.