Film bulk acoustic resonator and filter
A thin-film bulk acoustic wave and resonator technology, which can be used in device parts, device material selection, piezoelectric devices/electrostrictive devices, etc., and can solve problems such as characteristic degradation
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no. 1 approach
[0055] Figure 9A A plan view of the resonator according to the first embodiment is illustrated. Figure 9B exemplifies along Figure 9A Cutaway view of the A-A line extraction. Figure 9C exemplifies along Figure 9A Cutaway view of the B-B line extraction. A cavity 46 (via hole) is formed in the Si (silicon) substrate 41 . On the substrate 41 , above the cavity 46 , a lower electrode 43 is provided. A piezoelectric thin film 44 made of AlN is provided on the lower electrode 43 . An upper electrode 45 is provided on the piezoelectric film 44 . The resonance region 50 is a region where the lower electrode 43 and the upper electrode 45 face each other across the piezoelectric film 44 . The supporting area 52 is composed of the lower electrode 43 and the piezoelectric film 44 on the cavity 46, and is arranged around the resonant area 50, except for the wiring portion 56 leading out the upper electrode 45 and its surroundings. The adjacent area 54 is composed of the subst...
no. 2 approach
[0111] Figure 21 A schematic sectional view of a resonator according to the second embodiment is illustrated. Such as Figure 21 As shown, the support area 52 is composed of the piezoelectric film 44 and the upper electrode 45 located above the cavity 46 . The adjacent area 54 is composed of the substrate 41 , the piezoelectric film 44 and the upper electrode 45 . A cavity 46 is formed in the resonance region 50 as well as the support region 52 . The lower electrode 43 is formed in the resonance region 50 . The piezoelectric film 44 and the upper electrode 45 are formed in the resonance region 50 , the support region 52 and the adjacent region 54 . other structures with Figure 13 The structure of the first embodiment shown is the same.
[0112] Figures 22A to 22C A schematic diagram illustrating the calculated scattering characteristics of the resonance region 50 , the support region 52 and the adjacent region 54 in the resonator according to the second embodiment is...
no. 3 approach
[0115] Figure 23 A schematic sectional view of a resonator according to the third embodiment is illustrated. Such as Figure 23 As shown, the support region 52 is composed of the lower electrode 43 and the piezoelectric film 44 located above the cavity 46 . Adjacent region 54 consists of piezoelectric film 44 over cavity 46 . The cavity 46 and the piezoelectric film 44 are formed in the resonant region 50 , the support region 52 and the adjacent region 54 . The lower electrode 43 is formed in the resonance region 50 and the support region 52 . The upper electrode 45 is formed in the resonance region 50 . other structures with Figure 13 The structure of the first embodiment shown is the same.
[0116] Figures 24A to 24C A schematic diagram showing the calculated scattering properties of the resonance region 50 , the support region 52 and the adjacent region 54 in the resonator according to the third embodiment. Figure 24A corresponds to Figure 15A . Such as Fig...
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