To provide a thin film bulk acoustic resonator including a cavity structure capable of suppressing generation of spurious vibration caused by reflecting, within a substrate, vibration being leaked from a layered resonator to the substrate.
A thin film bulk acoustic resonator 11 includes a substrate 30 comprising a first principal surface 30A and a second principal surface 30B opposite thereto and a layered resonator 20 layered on the first principal surface 30A. The layered resonator 20 includes a first electrode 23 layered on the first principal surface 30A, a piezoelectric film 22 layered on the first electrode 23, and a second electrode 21 layered on the piezoelectric film 22. On the substrate 30, a cavity 31 is formed, which is opened perpendicularly to the second principal surface 30B, at a position corresponding to the layered resonator 20. In the cavity 31, a concave portion 32A is formed which is recessed inside the substrate.
KUROKI KOJI
INUBUSHI KAZUMI
TSUBOUCHI KAZUO
TAKAGI SUNAO
NAKASE HIROYUKI
KAMEDA TAKU
AOTA TAKETSUGU
SAKU TAISHIN
TANIFUJI SHOICHI
Shinji Oga
Toshifumi Onuki
Takuji Fukasawa
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