| 摘要 |
<p>An acoustical resonatorÄ20, 40, 110Ü and a method for making the same. A resonator according to the present invention includes a layer of piezoelectric materialÄ22, 42, 112Ü sandwiched between first and second electrodes. The first electrodeÄ23, 45, 111Ü includes a conducting sheet having a RMS variation in height of less than 2 mu m. The resonator bridges a cavityÄ102Ü in a substrateÄ101Ü on which the resonator is constructed. The resonator is constructed by creating a cavityÄ102Ü in the substrateÄ101Ü and filling the same with a sacrificial material Ä105Ü that can be rapidly removed from the cavityÄ102Ü after the deposition of the various layers making up the resonator. The surface of the filled cavityÄ102Ü is polished to provide a RMS variation in height of less than 0.5 mu m. The first electrodeÄ23, 45, 111Ü is deposited on the polished surface to a thickness that assures that the RMS variation in height of the metallic layer is less than 2 mu m. The piezoelectric layer is deposited on the first electrodeÄ23, 45, 111Ü and the second electrodeÄ21, 44, 113Ü is then deposited on the piezoelectric layer. The sacrificial material Ä105Ü is then removed from the cavityÄ102Ü by opening vias into the cavityÄ102Ü and removing the material through the vias. The preferred sacrificial material Ä105Ü is phophor-silica-glass. <IMAGE></p> |
