Morphological evolution of polished single crystal (100) diamond surface exposed to microwave hydrogen plasma

It is shown that exposure of polished single crystal diamond surfaces to microwave hydrogen plasma at optimized conditions may be applied as a very efficient method for the smoothing out of single crystal diamond surfaces. The effect of microwave (MW) hydrogen plasma exposure on the morphology of mechanically polished natural single crystal (100) oriented diamond type 2a surfaces is reported. It is shown that the surface morphology is very sensitive to plasma power and exposure time. Under appropriate plasma exposure conditions the diamond surfaces smooth out as reflected in the decrease in the number and depth of the polishing scratches or lines. However adverse effects on the surface morphology through the formation of pits were found to occur upon long exposure times and high plasma power. A systematic study of the influence of hydrogen microwave plasma power and exposure time on the diamond surface morphology is presented. The morphology of the diamond surfaces at the different stages was monitored with sub-nano-metric resolution by atomic force microscopy and scanning electron spectroscopy.