基于单晶TMR+MEMS原理的高灵敏低噪声新型复合磁传感器研究

Magnetic sensors based on Tunnel magnetoresistance (TMR) effect, play a significant role in medical, industrial and military application due to their advantage of high sensitivity at room temperature, high space resolution, low power consumption and small size. They have attracted great research interest in the field of magnetic sensing and spintronic. Although present TMR magnetic sensors have very high sensitivity, their intrinsic 1/f noise in the low frequency range are too large, which limit their application for detecting weak magnetic field in DC or low frequency range. To solve this problem, we propose to develop a novel high-sensitivity low-noise hybrid magnetic sensor based on single crystalline TMR+MEMS strategy. This TMR+MEMS structure can modulate the detected magnetic field from high noise low frequency range to low noise high frequency range, which can thoroughly overcome the 1/f noise problem in TMR device. Research in this project is aiming at establishing foundation to develop high performance magnetic sensors for low frequency weak magnetic field detecting. Details are as follow: (1) Study the underlying mechanism and method of fabricating high quality single crystalline TMR device on Si(001) substrate; (2) Build up theoretical model and optimize structure designing and fabrication process for MEMS package; (3) Study the optimal integrating process for combining TMR device and MEMS package, fabricate the sensor prototype and testing its performance.

TMR磁传感器具有室温下的高灵敏、高分辨、低功耗、小体积等优点, 在医疗、工业、军事等领域具有重要的应用价值，已成为磁传感和自旋电子领域的研究热点之一。现有的TMR磁传感器灵敏度虽高，但低频区的本征1/f噪声较大，无法应用到直流和低频微弱磁场检测上。针对上述问题，我们提出一种基于单晶TMR+MEMS原理的高灵敏低噪声新型复合磁传感器设计方案。这种TMR+MEMS结构理论上可将待测磁场信号从高噪声的低频范围调制到低噪声的高频范围，从而彻底克服TMR器件低频区本底噪声大的缺点。本项目旨在为研制高性能低频弱磁传感器奠定基础，主要研究内容如下：1. 研究高性能单晶TMR器件在Si(001)基片上外延生长的机理与方法；2. 建立理论模型，优化MEMS组件的设计与制备；3. 开展TMR+MEMS的集成工艺研究，确定最佳工艺路线，制作出传感器原型器件并建立测试平台，进行器件综合性能的测试。

TMR磁传感器具有室温下的高灵敏、高分辨、低功耗、小体积等诸多优点，已成为磁传感和自旋电子领域的研究热点之一。现有的TMR磁传感器灵敏度虽高，但低频区的本征1/f噪声较大，无法应用到直流和低频微弱磁场检测上。针对上述问题，本项目提出了一种基于单晶TMR+MEMS原理的高灵敏低噪声新型复合磁传感器设计方案。这种TMR+MEMS结构可将待测磁场信号从高噪声的低频范围调制到低噪声的高频范围，从而抑制低频1/f噪声，克服TMR器件低频区本底噪声大的缺点。本项目基于以上思路，实现了高性能TMR器件在单晶Si(001)基片上外延生长，阐明了其生长机理，掌握了其制备流程及关键技术，探索出可提升TMR器件性能的高自旋极化率薄膜新材料，开发了TMR器件和MEMS组件集成一体化的设计和制备流程，研制了基于TMR+MEMS原理的低噪声高灵敏度复合磁传感器样机，初步实现了该传感器在触觉传感、人机交互等方面的应用验证。. 本项目实施过程中，在Microsystems & Nanoengineering，Biosensors，Advanced Sensor Research等传感器领域高水平期刊发表论文15篇，其中SCI/EI检索论文12篇；申请中国发明专利11项，授权3项；1人次入选中国科学院“百人计划”，1人次入选第七届中国科协青年托举人才；培养博士生6人，硕士生1人，其中2人获得全国磁性材料与器件大会研究生学术新锐奖。