Birch, Stewart, Kolasch & Birch, LLP.
Film bulk acoustic wave device
There is provided a film bulk acoustic wave device comprising: a silicon substrate 1, a dielectric film 21 including a silicon nitride 16 formed on the substrate 1 and a silicon oxide 2 on the silicon nitride 16, a bottom electrode 3 formed on the dielectric film 21, a piezoelectric film 17 formed on the bottom electrode 3, and a top electrode 5 formed on the piezoelectric film 17, wherein a via hole is formed in such a manner that the thickness direction of a part of the silicon substrate 1 which is opposite to a region including a part where the top electrode 5 exists is removed from the bottom surface of the silicon substrate 1 to a boundary surface with the silicon nitride 16. 
Mitsubishi Denki Kabushiki Kaisha
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inventional inventional inventional inventional additional inventional
Fusaoki Chisako Shusou Akira Kenji Tsutomu Koji Koichiro
Uchikawa Maeda Wadaka Yamada Yoshida Nagatsuka Ibata Misu