A Miniaturized Piezoelectric MEMS Accelerometer with Polygon Topological Cantilever Structure

Area of Science:

• Microelectromechanical Systems (MEMS)
• Solid-State Physics
• Materials Science

Background:

• Miniaturized accelerometers are crucial for various sensing applications.
• Optimizing MEMS accelerometer design is key to improving performance metrics like sensitivity and frequency response.
• Polygonal topologies offer potential for novel MEMS device structures.

Purpose of the Study:

• To propose and analyze a miniaturized piezoelectric MEMS accelerometer with a polygonal topology.
• To investigate the impact of beam stiffness on accelerometer performance.
• To compare the performance of a novel design with shorter fixed sides against one with larger fixed sides.

Main Methods:

• Theoretical and finite element modeling to analyze beam stiffness effects.
• Fabrication of piezoelectric MEMS accelerometers using Cavity-SOI substrates and aluminum nitride (AlN) piezoelectric film.
• Experimental characterization of accelerometer performance, including natural frequency, sensitivity, linearity, resolution, and minimum detectable signal.

Main Results:

• The proposed polygonal topology with shorter fixed sides exhibits higher voltage sensitivity.
• Decreasing device stiffness leads to a lower natural frequency and increased output signal.
• The fabricated accelerometer demonstrates good linearity (<2 g) with a measured natural frequency of 98 kHz and sensitivity of 1.553 mV/g at 400 Hz.

Conclusions:

• The miniaturized piezoelectric MEMS accelerometer based on polygonal topology offers enhanced voltage sensitivity.
• The design provides a significant improvement (22.48%) in output voltage sensitivity compared to traditional trapezoidal cantilevers.
• This work contributes a high-performance MEMS accelerometer suitable for demanding sensing applications.