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Bridge Resistance Compensation for Noise Reduction in a Self-Balanced PHMR Sensor
Jaehoon Lee1, Changyeop Jeon1, Taehyeong Jeon1
1Department of Emerging Materials Science, DGIST, Daegu 42988, Korea.
Sensors (Basel, Switzerland)
|June 2, 2021
Summary
Researchers developed a novel self-balanced bridge magnetic sensor using planar Hall magnetoresistance technology. This microelectromechanical system (MEMS) sensor significantly reduces low-frequency noise, achieving ultra-high detectivity for advanced applications.
Area of Science:
- Physics
- Electrical Engineering
- Materials Science
Background:
- Advanced microelectromechanical system (MEMS) magnetic field sensors require ultra-high detectivity for low magnetic field applications.
- Existing MEMS magnetic sensors face limitations in detection limits and noise reduction.
Purpose of the Study:
- To develop a novel resistance compensator integrated self-balanced bridge type magnetic sensor.
- To reduce low-frequency noise in the 0.5 Hz to 200 Hz range for enhanced magnetic field detection.
Main Methods:
- Utilized a NiFe/IrMn bilayer structure within a planar Hall magnetoresistance (PHMR) framework.
- Integrated a resistance compensator with a self-balanced bridge sensor architecture.
- Analyzed sensor noise spectral density as a function of temperature and operating power.
Main Results:
- Achieved substantial improvement in the sensor noise level through offset voltage compensation at the wafer level.
- Identified electronic and magnetic noise components.
- Demonstrated a compact and cost-effective alternative to marketable MEMS MR sensors.
Conclusions:
- The proposed sensor architecture offers a significant advancement in MEMS magnetic sensor technology.
- The device achieves a lowest noise level of approximately 3.34 nV/Hz at 100 Hz.
- This technology enables ultra-high detectivity for low magnetic field sensing applications.
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