Ultrasonic transducer array design for medical imaging based on MEMS technologies

Piezoelectric micromachined ultrasonic transducer (pMUT) is a new approach to form high frequency arrays for real-time 3-D medical imaging. pMUT arrays based on SOI-Si bonding and PZT-coated membrane structures have been designed in this paper. After simulation, the 6×6 ultrasonic transducer array was fabricated and characterized. The total array area is approximately 2.0 mm by 2.0 mm. The micrograph of the device shows that the physical parameters are consistent with the designed value. The impedance-frequency spectrum of the pMUT was measured by HP 4194A impedance phase analyzer. Resonance frequency and effective electro-mechanical coupling coefficient can be deduced from it. The resonance frequency is 980 KHz, and the effective electro-mechanical coupling coefficient is about 4.64%. Due to its performance, it is promising for medical ultrasonic imaging applications.