Design and Measurement of Microelectromechanical Three-Axis Magnetic Field Sensors Based on the CMOS Technique.

Area of Science:

• Microelectromechanical Systems (MEMS)
• Semiconductor Device Physics
• Magnetic Field Sensing

Background:

• Accurate magnetic field sensing is crucial for various applications.
• Existing magnetic field sensors often face challenges with cross-sensitivity and integration.
• Microelectromechanical systems (MEMS) offer miniaturization and potential for enhanced performance.

Purpose of the Study:

• To design, fabricate, and characterize a novel MEMS three-axis magnetic field sensor (MFS).
• To investigate the performance of the MFS using semiconductor simulation and experimental measurements.
• To minimize cross-sensitivity in a multi-axis magnetic field sensing configuration.

Main Methods:

• Utilized Sentaurus TCAD for semiconductor device simulation.
• Designed a unique MFS structure with independent z-MFS and y/x-MFS components.
• Fabricated the MFS using the TSMC 1P6M 0.18 μm CMOS process.
• Incorporated four additional collectors in the z-MFS to boost sensitivity.

Main Results:

• The MFS achieved a low cross-sensitivity of less than 3%.
• Demonstrated high sensitivities for each axis: z-MFS (237 mV/T), y-MFS (485 mV/T), and x-MFS (484 mV/T).
• The simulation and experimental results validated the sensor's performance.

Conclusions:

• The developed MEMS MFS effectively measures magnetic fields in three axes with high precision.
• The novel design successfully reduces cross-sensitivity, enhancing measurement accuracy.
• The integration of MEMS technology with CMOS processes enables efficient fabrication of advanced magnetic sensors.