This application relates to the field of
semiconductor technology, specifically to a MEMS piezoelectric
loudspeaker and acoustic device, including a substrate and a piezoelectric stack disposed on the substrate; the piezoelectric stack has multiple tangents extending from the geometric center of the piezoelectric stack to the edge of the piezoelectric stack, forming multiple
cantilever beams arranged rotationally symmetrically about the geometric center; each
cantilever beam has a fixed edge away from the geometric center; at least two of the
cantilever beams have trench structures on the substrate, the trench structures being located close to the fixed edge of the cantilever beam. This application can reduce peaks at resonant frequencies and effectively expand the frequency bandwidth, improving overall audio performance; in addition, this application can also reduce diaphragm stiffness, thereby significantly enhancing its low-frequency deformation capability and optimizing the low-
frequency sound pressure level curve.