First-Principles Calculations and PMUT Applications of Piezoelectric Thin-Film Materials

Area of Science:

• Materials Science
• Physics
• Engineering

Background:

• High-performance piezoelectric micromachined ultrasonic transducers (PMUTs) are vital for portable medical imaging and sensing.
• Variability in piezoelectric thin films like ScAlN and PZT can lead to inaccurate material parameters, affecting device simulation accuracy.

Purpose of the Study:

• To introduce an optimization framework combining first-principles calculations and multiphysics simulations for enhanced PMUT design.
• To improve simulation accuracy for PMUTs by addressing inconsistencies in piezoelectric material parameters.

Main Methods:

• Atomistic calculations were performed to analyze the intrinsic properties of PZT and ScAlN.
• Finite-element models were calibrated using first-principles data to address missing or inaccurate material parameters.
• An efficient analytical acoustic-field model was developed to reduce computational cost compared to full-wave simulations.

Main Results:

• PZT was confirmed to be better suited for actuation due to its higher electromechanical coupling coefficient.
• The developed analytical model significantly reduced computational cost while maintaining accuracy for large-array topology optimization.
• Hexagonal PMUT elements demonstrated superior performance over circular elements, achieving higher Sound Pressure Level (SPL) and operating frequency.

Conclusions:

• The proposed modeling approach, based on intrinsic material properties, provides a robust theoretical foundation for designing high-precision, low-power ultrasonic devices.
• Optimized PMUT designs using this framework can lead to improved spatial resolution and sensitivity in medical imaging and sensing.