| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 94 === This work presents an innovative design and fabrication of phononic crystals integrated with two sets of interdigital (IDT) electrodes for frequency band selection of surface acoustic waves (SAW). Analogous to the band-gap generated by photonic crystals, the phononic crystals can prohibit the propagation of elastic waves with either specific incident angles or certain bandwidth. Both IDT electrodes are deposited and patterned on a thin piezoelectric layer. Both surface and bulk micromachining are employed and integrated to fabricate the crystals as well as SAW resonator and receiver altogether. Firstly, a 1.5-micron zinc oxide, which provides well-defined central frequency, is sputtered and patterned onto silicon substrate. Second, the IDT electrodes are evaporated and patterned by lift-off technique. Then the exposed silicon substrate is etched using DRIE to generate two dimensional phononic crystals. To tune the prohibited SAW bandwidth, the crystal pores are filled with copper by electro plating.
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