  Recent advances in focused ion beam technology have enabled high-resolution,
direct-write nanofabrication using light ions. Studies with light ions to date
have, however, focused on milling of materials where sub-surface ion beam
damage does not inhibit device performance. Here we report on direct-write
milling of single crystal diamond using a focused beam of oxygen ions. Material
quality is assessed by Raman and luminescence analysis, and reveals that the
damage layer generated by oxygen ions can be removed by nonintrusive
post-processing methods such as localised electron beam induced chemical
etching.
