Development of low loss and high Q value diamond surface acoustic wave (SAW) devices consisting of fine-grained diamond

摘要

Diamond is one of the most interesting materials for surface acoustic wave devices due to its highest sound velocity among all the materials, which yields high frequency SAW devices. Sumitomo Electric has already studied devices using diamond and succeeded in fabricating the diamond SAW devices for high frequency from 2 to 5 GHz. We recently succeeded in developing a fine-grained diamond film which led to lower insertion loss and higher Q value due to its lower propagation loss in SAW devices. Using the fine-grained diamond, we fabricated several kinds of GHz-range narrow band SAW devices with SiO{sub}2/ZnO/diamond/Si structure. The total propagation loss was investigated from the characteristics of these devices. The propagation loss in this diamond film was about two-third of that in our standard diamond film. The insertion loss was from 1 to 3 dB lower and the Q value was about 200 higher.