Thin Film PZT-Based PMUT Arrays for Deterministic Particle Manipulation

Area of Science:

• Materials Science
• Acoustics
• Microfluidics

Background:

• Piezoelectric micromachined ultrasonic transducers (PMUTs) are increasingly utilized for microscale applications.
• Particle manipulation using acoustic waves offers a contactless method for controlling microparticles.

Purpose of the Study:

• To design, fabricate, and characterize PZT-based PMUTs for particle manipulation.
• To demonstrate the capability of PMUTs for trapping and controlling microparticles using acoustophoresis.

Main Methods:

• Fabrication of PMUTs with a 60 µm diaphragm diameter and ~8 MHz resonant frequency.
• Testing PMUT performance in water, measuring acoustic pressure output (9.5 kPa at 7.5 mm).
• Demonstration of particle trapping and manipulation of 4 µm silica beads using 5 Vpp unipolar excitation.

Main Results:

• Successful trapping and deterministic control of multiple silica beads via acoustophoresis without microfluidic flow.
• Particle movement towards high-pressure areas on the diaphragm, consistent with simulations.
• Generation of unique bead patterns and particle levitation planes at frequencies up to 60 MHz, significantly beyond the operational bandwidth.

Conclusions:

• PZT-based PMUTs are effective for contactless microparticle manipulation.
• Acoustic manipulation using PMUTs allows for precise pattern generation and levitation.
• The demonstrated capabilities open avenues for advanced microparticle handling in various scientific and technological fields.