Modeling and Measurement of Noise in Aluminium Nitride Piezoelectric MEMS

ABSTRACT This study presents a comprehensive investigation into the noise behavior of piezoelectric MEMS devices using a combined experimental and modeling‐based approach. A detailed analysis is performed to decompose the total noise into its constituent sources, including thermal noise in the piezoelectric layer, input voltage noise of the amplifier, input current noise of the amplifier, and the thermal noise of the bias resistor within the amplifier. Noise spectral density measurements are carried out from a few Hz to 1 MHz. They exhibit a pronounced 1/f characteristic at lower frequencies, where amplifier‐related noise sources are significant. The proposed electrical noise modeling framework accurately reproduces the experimental data, validating its effectiveness in capturing noise contributions across the operating bandwidth. Additionally, temperature‐dependent measurements reveal reductions in both capacitance (3%) and loss tangent (75%) of the aluminum nitride piezoelectric layer when cooled from 300 to 80 K, correlating with a corresponding decrease in the device's thermal noise. These results provide valuable insights into the optimization of piezoelectric MEMS devices for low‐noise applications, particularly in cryogenic environments, and contribute to advancing the design of next‐generation high‐sensitivity MEMS/NEMS sensors and actuators.