隧穿磁阻传感器研究进展

传感器作为物联网技术的基石,在人们的生产生活中发挥着重大作用.其中,基于隧穿磁阻效应(tunneling magnetoresistance, TMR)的磁传感器具有灵敏度高、尺寸小、功耗低等优点,在导航定位、生物医学、电流检测和无损检测等领域具有极大的应用前景.本综述以TMR传感器技术路线的发展为核心,囊括了从基本传感单元到三维空间磁场检测,再到实际应用的多个研究重点.首先,介绍了TMR传感器发展历程并阐明其基本工作原理,讨论了提高单个传感单元磁隧道结输出线性度的方法.接下来,详细介绍了传感器的重要电路结构—惠斯通电桥,以及制备TMR全桥结构的多种工艺方法.进一步,从三维空间磁场检测这一市场需求入手,深入讨论了基于TMR传感器的三维传感结构的设计和制备方法.同时,以传感器灵敏度和噪声水平这两大基本性能为切入点,列举了TMR传感器性能的优化方案.最后,本文对TMR传感器的应用展开了详细介绍,以自旋麦克风,生物传感器两个新兴应用为例,对TMR传感器未来在物联网中的发展和应用进行了展望.

Research progress of tunneling magnetoresistance sensor

Sensors play an important role in Internet of Things(IoT)industry and account for a rapidly growing market share.Among them,the magnetic sensor based on tunneling magnetoresistance(TMR)effect possesses great potential applications in the fields of biomedical,navigation,positioning,current detection,and nondestructive testing due to its extremely high sensitivity,small device size and low power consumption.In this paper,we focus on the development of TMR sensor technology routes,covering a series of research advances from a sensor transducer to three-dimensional magnetic field detection,and then to the applications.Firstly,we recall the development history of TMR sensors,explain its working principle,and discuss the method to improve the output linearity of single magnetic tunnel junction.Next,we state the Wheatstone-bridge structure,which can inhibit temperature drift in detail and review several methods of fabricating the full bridge of TMR sensors.Furthermore,for the market demand of three-dimensional magnetic field detection,we summarize the methods of designing and fabricating three-dimensional sensing structure of the TMR sensor.At the same time,we list several optimization schemes of TMR sensor performance in terms of sensitivity and noise level.Finally,we discuss two types of emerging applications of TMR sensors in recent years.The TMR sensors can also be used in intelligence healthcare due to their ultra-high sensitivity.In addition,devices from the combination of spin materials and MEMS structure have attracted wide attention,especially,because of the large commercial market of microphones,spin-MEMS microphones utilized TMR techniques will be the next research hotspot in this interdisciplinary field.