Reactive ion beam machining of diamond using an ECR-type oxygen source

Reactive ion beam machining of diamond chips with oxygen ions using a Kaufman-type apparatus has been investigated. This paper reports machining characteristics of single crystal diamond chips processed with an oxygen ion beam using an electron cyclotron resonance (ECR)-type apparatus. The specific machining rate increases with increase in ion energy, reaches a maximum rate at an ion energy of 300 eV, then decreases gradually with further increase in ion energy. The specific machining rate obtained with 1000 eV oxygen ions increases with increase in ion incident angle and reaches a maximum rate at an ion incident angle of 40 degrees, then decreases with increase in ion incident angle. The specific machining rate obtained with 500 eV oxygen ions decreases with increase in ion incident angle. The specific machining rate for 500 eV oxygen ions at an ion incident angle of 0 degrees is 12 times greater than that for argon ions. Furthermore, the surface roughness of diamond chips before and after oxygen ion beam machining was evaluated using an atomic force microscope (AFM) and a scanning electron microscope (SEM). It was found that the surface roughness increases with increase in ion incident angle, and decreases with increase in ion energy.