Near-zero stiffness accelerometer with buckling of tunable electrothermal microbeams

Area of Science:

• Micro-Electro-Mechanical Systems (MEMS)
• Mechanical Engineering
• Materials Science

Background:

• Pre-shaped microbeams (curved or inclined) are integral to MEMS, offering tunable stiffness properties.
• These microbeams enable a broad spectrum of positive and negative stiffness tuning along their motion axis.
• Tuning stiffness is crucial for optimizing MEMS device performance, particularly in sensing applications.

Purpose of the Study:

• To develop and demonstrate a tunable spring mechanism for micro-machined accelerometers.
• To investigate the electrothermal tuning of pre-shaped microbeams for negative stiffness behavior.
• To enhance accelerometer sensitivity and resolution through stiffness modulation.

Main Methods:

• Utilizing pre-shaped microbeams with opposite curvature in a parallel configuration.
• Employing electrothermal tuning to adjust the stiffness of the microbeam mechanism.
• Implementing the tunable spring in a capacitive micromachined accelerometer prototype.

Main Results:

• Achieved near-zero or negative stiffness behavior through electrothermal tuning.
• Demonstrated a significant gain of over 55 times in accelerometer sensitivity.
• Observed promising enhancements in acceleration sensing resolution.

Conclusions:

• The developed tunable spring mechanism offers a simple yet effective method for enhancing accelerometer performance.
• Electrothermal tuning of pre-shaped microbeams provides a viable pathway to significantly boost sensitivity and resolution in MEMS accelerometers.
• This technology holds potential for achieving unprecedented performance in micro-machined accelerometers for various applications.