PiezoMEMS Fabrication on Flexible Stainless-Steel Substrates

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Flexible piezoelectric micromachined ultrasound transducers (PMUTs) are crucial for advanced sensing and imaging applications.
• Developing robust fabrication methods for PMUT arrays on versatile substrates remains a key challenge.

Purpose of the Study:

• To establish a bottom-up fabrication approach for flexible PMUT arrays on stainless-steel substrates.
• To characterize the electrical properties of the fabricated PMUT devices.

Main Methods:

• Utilized chemical solution deposition for a lead zirconate titanate (PZT) based piezoelectric layer on stainless-steel foils.
• Employed lithography for patterning electrodes and piezoelectric layers.
• Applied nickel electroplating to create locally stiffened areas for defining deflection zones.

Main Results:

• Successfully fabricated flexible PMUT devices on stainless-steel substrates.
• Achieved a permittivity of 283 ± 9 and a loss tangent <1.5% at 1 kHz.
• Measured a remanent polarization of 38 ± 0.3 μC/cm².

Conclusions:

• The developed bottom-up fabrication method is effective for producing flexible PMUT arrays.
• The fabricated devices exhibit promising piezoelectric properties for ultrasound applications.
• This approach offers a pathway for integrating PMUTs onto flexible and robust stainless-steel platforms.