Piezoelectric thin films for a high frequency ultrasound transducer with integrated electronics

Lead zirconate titanate piezoelectric films were integrated into prototype one-dimensional array transducers. The geometry used for transducer arrays is a xylophone-bar type with a length:width aspect ratio greater than 5:1 in order to isolate the desired resonance modes. The PZT and remaining films in the stack were patterned using ion-beam etching and partially released from the underlying silicon substrate by XeF₂ etching. Impedance measurements on the fabricated structures showed resonance frequencies between 3 and 70 MHz for fully and partially released structures depending on the transducer dimensions and vibration modes. In-water transmit and receive functionalities have been demonstrated. A bandwidth on receive of 66 % has been determined for partially released structures.