Study of Rectangular Membrane PMUT-Based Acoustic Streaming Micropump

A novel, CMOS compatible ScAlN-based micropump driven by a discrete rectangular membrane piezoelectric micromachined ultrasonic transducer (PMUT) array is developed. PDMS containing a microfluidic channel is bonded to the top of the actuator. When subjected to a phase-delayed AC electrical excitation, the PMUT array generates a directional acoustic wave within the microfluidic channel, producing a directional streaming flow pattern. The compact device, with an active area of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.2 \times 1.6\ \text{mm}^{2}$</tex>, achieved a mean flow velocity of 0.16 mm/min, which is consistent with predictions from numerical multiphysics simulations. Further optimization via numerical simulations indicates augmentation of mean flow velocity up to 2.1 mm/min is possible. The micropump has the potential for integration into μTAS applications, where liquid control and delivery in a small form factor are critical.