2results about How to "High electromechanical coupling efficiency" patented technology

The invention provides a piezoelectric micromechanical ultrasonic transducer, a control method and an array. The piezoelectric micromechanical ultrasonic transducer (100) comprises: a substrate (101) provided with a back cavity (102); the composite diaphragm structure is arranged above the back cavity and comprises a piezoelectric film layer (105) used for transmitting and receiving ultrasonic waves based on the piezoelectric effect; the phase change tuning layer (110) is mechanically coupled with the piezoelectric thin film layer and is prepared from a nonvolatile material with reversible mechanical properties, the nonvolatile material has at least two stable phase forms under external excitation, and different phase forms correspond to different mechanical properties; the change of the mechanical property causes the change of the overall effective rigidity of the composite diaphragm structure; and the excitation structure (108) is coupled with the phase change tuning layer and is used for applying external excitation to the phase change tuning layer so as to drive the nonvolatile material to carry out nonvolatile switching among different phase forms, so that frequency tuning of the piezoelectric micromechanical ultrasonic transducer is realized.

The application discloses a preparation process of a lead zirconate titanate (PZT) film layer, a film layer structure and application thereof, and relates to the technical field of piezoelectric material film layer preparation. The preparation process comprises the following steps: S1, forming a low tensile stress silicon nitride layer on the surface of a substrate, which is used for homogenizing the in-plane stress gradient of a wafer; and S2, forming a piezoelectric functional layer on the surface of the silicon nitride layer in a sputtering mode, wherein the piezoelectric thin film material of the piezoelectric functional layer is lead zirconate titanate (PZT). The film layer structure and the preparation process thereof adopt the silicon nitride layer to relieve the thermal mismatch stress of the piezoelectric functional layer system, can improve the piezoelectric constant e31 of the central region of the wafer, and improve the uniformity of the whole wafer.