Piezoelectric micromachined ultrasonic transducer and piezoelectric micromachined ultrasonic transducer array

A piezoelectric micromachined ultrasonic transducer array, comprising

• a silicon substrate;
• and
• a plurality of piezoelectric micromachined ultrasonic transduction elements arranged on the silicon substrate and arranged in an array, and each piezoelectric micromachined ultrasonic transduction element comprising:
• a first protective layer arranged on the silicon substrate and provided with a cavity, and the cavities of the piezoelectric micromachined ultrasonic transduction elements communicating with one another;
• a piezoelectric composite film arranged on the first protective layer, wherein a vertical projection of the piezoelectric composite film partially overlaps with the cavity, the piezoelectric composite film is provided with at least two communicating holes, and the two communicating holes penetrate the piezoelectric composite film and communicate with the cavity;
• and
• a second protective layer on the surface of the piezoelectric composite film, and filling the two communicating holes to close the cavity,
• wherein at least one of the piezoelectric micromachined ultrasonic transduction elements comprises a supporting pillar, the supporting pillar is in the cavity, and a part of the bottom of each piezoelectric composite film is in contact with the supporting pillar;
• the non-supporting pillar regions in the cavity communicate with each other;
• the shortest distance between the wall of the first protective layer and the supporting pillar is a first distance;
• the distance between the two communicating holes being greater than twice of the first distance;
• and a ratio of a height of the supporting pillar to the first distance being 1/70 to 1/200, and a width of the supporting pillar being 3-10 um.