Single crystal film bulk acoustic wave resonator, and preparation method and application thereof

A single crystal film bulk acoustic wave resonator, comprising a substrate layer, a Bragg reflection layer, a first bonding layer, a second bonding layer, a piezoelectric layer and an electrode layer sequentially from bottom to top, wherein a width of the electrode layer is smaller than a width of the piezoelectric layer;

• the resonator further comprises a first silicon oxide layer and a second silicon oxide layer, the first silicon oxide layer and the second silicon oxide layer are arranged to surround the first bonding layer and the second bonding layer respectively, and a plurality of first air holes horizontally arranged and a plurality of second air holes horizontally arranged are respectively formed in the first silicon oxide layer and the second silicon oxide layer;
• each of the plurality of first air holes corresponds to and is communicated with a respective one of the plurality of second air holes;
• and the piezoelectric layer is made of AlN or lithium niobate.