A 4 mm² Double Differential Torsional MEMS Accelerometer Based on a Double-Beam Configuration

Area of Science:

• Microelectromechanical Systems (MEMS)
• Sensor Technology
• Mechanical Engineering

Background:

• Conventional torsional MEMS accelerometers typically use a single proof mass and torsional beam.
• Existing designs can be large, limiting miniaturization in various applications.
• High-g acceleration can induce significant stress, potentially leading to device failure.

Purpose of the Study:

• To design and simulate a significantly smaller double differential torsional MEMS accelerometer.
• To investigate a novel double-beam configuration for enhanced structural integrity and performance.
• To evaluate the performance metrics including sensitivity, nonlinearity, and temperature stability.

Main Methods:

• Design of a double differential torsional MEMS accelerometer utilizing a double-beam structure.
• Finite Element Method (FEM) simulations to analyze mechanical properties and performance.
• Evaluation of key specifications: mechanical sensitivity, nonlinearity, stress distribution, noise, and temperature coefficient.

Main Results:

• Achieved a device area over 50 times smaller than traditional designs.
• Demonstrated high mechanical sensitivity (59.4 fF/g) and low nonlinearity (0.88%) for a ±15 g range.
• Showcased improved stress distribution, reduced noise (0.13 mg/√Hz), and excellent temperature stability (0.25 mg/°C).

Conclusions:

• The novel double-beam configuration enables significant miniaturization of MEMS accelerometers.
• The design maintains or improves critical performance specifications compared to conventional structures.
• The enhanced structural robustness reduces failure risk under high-g acceleration across all axes.