Ion beam assisted chemical etching of single crystal diamond chips

Ion beam assisted chemical etching (IBACE) of diamond chips with an argon ion beam and a reactive oxygen gas flux was investigated. The specific etching rate of single crystal diamond chips with a (100) oriented face increases with increasing ion energy ranging from 300 to 1000 eV. The specific etching rates of the chip processed with 500 eV and 1000 eV Ar⁺ ions increase with increasing oxygen partial pressure, and reach a maximum rate at an oxygen partial pressure of approximately 0.02 and 0.05 Pa, respectively, and then decrease gradually with increasing oxygen partial pressure. The specific etching rate of the chip for IBACE which includes both physical and chemical reactions is approximately two times greater than that for ion beam etching (IBE) which causes only a physical sputtering reaction. Futhermore, the surface roughness of diamond chips before and after IBACE was evaluated using an atomic force microscope (AFM). Consequently, the surface roughness of the chip for IBACE increases with increasing substrate temperature, whereas that for IBE (only Ar⁺ ions) is almost constant as a function of the substrate temperature ranging from room temperature to 400°C.