Sub-micrometer scale patterning on single-crystal diamond surface using focused ion beam and deep ultraviolet laser irradiations

In this study, a novel method is proposed for patterning the surface of a single-crystal diamond in the sub-micrometer scale using a combination of focused ion beam (FIB) and deep ultraviolet (DUV) laser irradiations. The surface area of the diamond irradiated by the FIB was selectively machined using a low-power DUV laser, whereas the non-FIB-irradiated area was hardly machined. Hence, diamonds can be patterned at the sub-micrometer scale by selectively machining the FIB-irradiated area using lasers. To investigate the machining characteristics in this process, the effects of the FIB and DUV laser-irradiation parameters were investigated. Consequently, the shape of the DUV-irradiated area was improved by applying the gallium removal step; debris was not formed. In addition, a structure with a maximum depth of approximately 80 nm was fabricated. The damage density induced by the FIB irradiation was employed to determine the depth induced by the FIB; the depth obtained using this method is more than twice that of the heating technique in air. A concave structure was fabricated based on these results. The results indicate that the proposed method is effective for fabricating sub-micrometer-scale structures on diamond surfaces.