Analysis and Guideline for Determining Piezoelectric Coefficient for Films With Substrate Constraint

Area of Science:

• Materials Science
• Electrical Engineering
• Physics

Background:

• Piezoelectric films are vital for electromechanical devices, requiring precise property measurements.
• Substrate constraints can compromise the accuracy and reliability of piezoelectric coefficient measurements.

Purpose of the Study:

• To identify and analyze factors affecting piezoelectric film property measurements.
• To provide guidelines for accurate and reliable piezoelectric coefficient measurements.

Main Methods:

• Theoretical finite element analysis (FEA).
• Experimental validation.
• Comparison of established piezoelectric measurement methods.

Main Results:

• Key factors influencing measurement accuracy include substrate-to-film Young's modulus ratio, electrode size-to-substrate thickness ratio, and test frequency.
• Lower substrate modulus and larger electrode-to-substrate thickness ratios increase bending effects and potential errors.
• High test frequencies can induce unreliable transversal displacement fluctuations.

Conclusions:

• Understanding substrate effects is critical for accurate piezoelectric film characterization.
• Established guidelines will enhance the reliability of piezoelectric coefficient measurements for electromechanical materials and devices.