| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 107 === In this study, the 3.5 GHz SMR filter is fabricated on sapphire substrate. The Bragg reflector is fabricated using molybdenum (Mo) and silicon dioxide (SiO2) as the high impedance and low impedance layers. The surface roughness is analyzed by atomic force microscope (AFM) and the thickness is observed by scanning electron microscope. The Bragg reflector of low surface roughness is obtained by adjusting the sputtering pressure and sputtering power. The AlN piezoelectric layer with highly c-axis orientation is obtained by adjusting the sputtering pressure and the sputtering power.
The resonators are fabricated and analyzed first in this study to construct the filters. The resonator at 2.75 GHz is fabricated using the optimized sputtering parameters, which shows the insertion loss of -7.34 dB, the electromechanical coupling coefficient of 1.02%，and the quality factor of 181. Then the resonator at 3.5 GHz is fabricated with the insertion loss of -9.39 dB, the electromechanical coupling coefficient of 1.88%, and the quality factor of 157.
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