Lee Jaehoon, Jeon Changyeop, Jeon Taehyeong, Das Proloy Taran, Lee Yongho, Lim Byeonghwa, Kim CheolGi
Department of Emerging Materials Science, DGIST, Daegu 42988, Korea.
Magnetics Initiative Life Care Research Center, DGIST, Daegu 42988, Korea.
Sensors (Basel). 2021 May 21;21(11):3585. doi: 10.3390/s21113585.
Advanced microelectromechanical system (MEMS) magnetic field sensor applications demand ultra-high detectivity down to the low magnetic fields. To enhance the detection limit of the magnetic sensor, a resistance compensator integrated self-balanced bridge type sensor was devised for low-frequency noise reduction in the frequency range of 0.5 Hz to 200 Hz. The self-balanced bridge sensor was a NiFe (10 nm)/IrMn (10 nm) bilayer structure in the framework of planar Hall magnetoresistance (PHMR) technology. The proposed resistance compensator integrated with a self-bridge sensor architecture presented a compact and cheaper alternative to marketable MEMS MR sensors, adjusting the offset voltage compensation at the wafer level, and led to substantial improvement in the sensor noise level. Moreover, the sensor noise components of electronic and magnetic origin were identified by measuring the sensor noise spectral density as a function of temperature and operating power. The lowest achievable noise in this device architecture was estimated at ~3.34 nV/Hz at 100 Hz.
先进的微机电系统（MEMS）磁场传感器应用要求在低磁场下具有超高的探测灵敏度。为了提高磁传感器的检测极限，设计了一种集成电阻补偿器的自平衡桥式传感器，用于降低0.5 Hz至200 Hz频率范围内的低频噪声。自平衡桥式传感器采用平面霍尔磁阻（PHMR）技术框架下的NiFe（10 nm）/IrMn（10 nm）双层结构。所提出的集成电阻补偿器的自桥式传感器架构为市售MEMS MR传感器提供了一种紧凑且成本更低的替代方案，可在晶圆级调整失调电压补偿，并显著提高传感器的噪声水平。此外，通过测量传感器噪声谱密度随温度和工作功率的变化，识别了电子和磁起源的传感器噪声成分。在该器件架构中，100 Hz时可实现的最低噪声估计约为3.34 nV/Hz。
