Structure of diamond surface defective layer damaged by hydrogen ion beam exposure

The influence of hydrogen ion beam exposure on diamond structure was investigated. Defects were created even when the extraction voltage was as low as 10 V, which was estimated by electron spin resonance (ESR) measurements. Fourier transform infrared spectroscopy (FTIR) revealed that a defective structure was similar to that of hydrogenated amorphous carbon (a-C:H). Low energy (extraction voltage ≤ 50 V) hydrogen ion beam exposure was found to remove a graphitic structure resulting from high temperature annealing of the defective layer. Based on the experimental results, elementary processes of hydrogen plasma etching by plasma-assisted chemical vapor deposition (CVD) at 800 °C are discussed.