High-SPL and Low-Driving-Voltage pMUTs by Sputtered Potassium Sodium Niobate


This work presents an air-coupled piezoelectric micromachined ultrasonic transducer (pMUT) with
high transmitting acoustic pressure by using sputtered potassium sodium niobate (K,Na)NbO3
(KNN) thin film with a high piezoelectric coefficient (e31 ~ 8-10 C/m2) and low dielectric constant
(er ~ 260-300) for the first time. The fabricated KNN pMUT with a resonant frequency at 104.5 kHz
has been tested to exhibit unprecedented results: (1) high sound pressure level (SPL) of 109 dB/V
at a distance of 10 cm, which is 8 times higher than that of AlN-based pMUTs at a similar
frequency; (2) low-voltage operation of only 4 volts peak-to-peak amplitude (Vp-p); and (3) good
receiving sensitivity. As such, this work presents a new class of high-SPL and low-driving-voltage
pMUTs for potential applications in various fields, including consumer electronics, such as but not
limited to haptic feedback, loudspeaker, and AR/VR systems.

Publication date: 
January 19, 2023
Publication type: 
Conference Paper (Proceedings)
Fan Xia, Yande Peng, Sedat Pala, Ryuichi Arakawa, Wei Yue, Pei-Chi Tsao, Chun-Ming Chen, Hanxiao Liu, Megan Teng, Jongha Park, and Liwei Lin, "High-SPL and Low-Driving-Voltage pMUTs by Sputtered Potassium Sodium Niobate" Proceedings of the 36th IEEE Micro Electro Mechanical Systems Conference, Jan. 2023.

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