Optical Characterization of Lorentz Force Based CMOS-MEMS Magnetic Field Sensor

Area of Science:

• Microelectromechanical Systems (MEMS)
• Solid-state Physics
• Sensor Technology

Background:

• Magnetic field sensors are increasingly vital due to enhanced sensitivity, resolution, and miniaturization.
• Lorentz force-based sensors offer a promising avenue for advanced magnetic field detection.

Purpose of the Study:

• To design, fabricate, and optically characterize a Lorentz force-based CMOS-MEMS magnetic field sensor.
• To evaluate the sensor's performance metrics including resonance frequency, quality factor, damping ratio, sensitivity, and resolution.

Main Methods:

• Fabrication using CMOS thin layers and dry post micromachining.
• Device structure release and packaging in DIP.
• Optical characterization of the resonating shuttle's amplitude change in response to magnetic fields.

Main Results:

• Experimental determination of resonance frequency (8164 Hz), quality factor (51.34), and damping ratio (0.00973).
• Static mode sensitivity of 0.034 µm/mT at 10 mA current.
• Resonant mode sensitivity of 1.35 µm/mT at 8 mA current.
• Achieved sensor resolution of 370.37 µT.

Conclusions:

• The developed CMOS-MEMS sensor demonstrates effective magnetic field sensing capabilities.
• The sensor's performance, particularly its sensitivity at resonance, highlights its potential for practical applications.
• Optical characterization provides a robust method for evaluating MEMS sensor performance.