Bulk acoustic wave resonator and method of forming same

The embodiment of the invention provides a bulk acoustic wave resonator and a forming method thereof. The forming method of the bulk acoustic wave resonator includes forming a sacrificial structure on a substrate, forming a seed layer on the sacrificial structure, forming a bottom electrode on the seed layer, forming a piezoelectric layer on the bottom electrode, forming a top electrode on the piezoelectric layer, removing the sacrificial structure to form a cavity, and etching the seed layer through the cavity. According to the embodiment of the invention, after the bottom electrode and the piezoelectric layer are formed, the seed layer in the active region of the bulk acoustic wave resonator is selectively removed. Therefore, the quality factor and/or the electromechanical coupling coefficient of the bulk acoustic wave resonator can be improved without deteriorating the quality of the bottom electrode and the piezoelectric layer. 本发明实施例提供一种体声波共振器及其形成方法。前述体声波共振器的形成方法包括：形成牺牲结构在基板上，形成晶种层在牺牲结构上，形成底电极在晶种层上，形成压电层