Ultra‐smooth single crystal diamond surfaces resulting from implantation and lift‐off processes

A method for obtaining a smooth, single crystal diamond surface is presented, whereby a sacrificial defective layer is created by implantation of a regular (4 nm roughness) Ib diamond plate. This was then graphitized by annealing before being selectively etched. We have used O+ at 240 keV, the main process variables being the ion fluence (ranging from 3 × 1015 to 3 × 1017 cm−2) and the final etching process (wet etch, H2 plasma, and annealing in air). The substrates were characterized by atomic force microscopy, optical profilometry and white beam X‐ray topography. The influence of the various process parameters on the resulting lift‐off efficiency and final surface roughness is discussed. An O+ fluence of 2 × 1017 cm−2 was found to result in sub‐nanometer roughness over tens of µm2.