Investigation of the thermal-chemical polishing and laser ablation of CVD diamond film

摘要

Owing to the rapid development in the mobile telecommunication and optoelectronic area, SAW(Surface Acoustic Wave) devices such as SAW-Resonator、 SAW-Duplexer and SAW-Sensors are in great demand. Crystals such as LiNbO{sub}3, LiTaO{sub}3, and Quartz are frequently used as the substrate material for SAW devices. However, the surface acoustic wave velocity obtainable on these materials is relatively low. ZnO/Diamond structure has attracted a lot of attentions and heavy investment recently just because diamond has the capability of producing very high surface acoustic wave (around 10000m/s). In the present study, the microwave CVD method was employed to produce epitaxial diamond films on silicon single crystal. Hot polishing together with laser ablation experiments were then conducted on the obtained diamond films. The underlying material removal mechanisms, microstructure of the machined surface and related machining conditions were also investigated. It was found that hot polishing was achievable on a rather simple setup and could remove the diamond film very effectively (～6μm/hr). Laser ablation, on the other hand, could improve the surface roughness from above 1μm to around 0.1μm in few minutes time. However, a scanning technique would be required if a large area was to be polished by laser and, as a consequence, it could be very time consuming.