MEMS加速度计微敏感结构的伽马辐照退化效应  

Gamma radiation induced degradation effect of MEMS capacitive accelerometer's micro-sensing part

作　　者：许蔚[1] 杨杰[1] 刘珉强 XU Wei;YANG Jie;LIU Minqiang(Institute of Electronic Engineering,China Academy of Engineering Physics,Mianyang Sichuan 621999,China)

机构地区：[1]中国工程物理研究院电子工程研究所,四川绵阳621999

出　　处：《太赫兹科学与电子信息学报》2022年第10期1101-1106,共6页Journal of Terahertz Science and Electronic Information Technology

基　　金：国家自然科学基金资助项目(61904165);电子元器件可靠性物理及其应用技术重点实验室基金资助项目(614280620190303)。

摘　　要：抗辐射的微机电系统(MEMS)加速度计在航天飞行器和核工业中有着广泛应用。当前的研究主要集中在MEMS测控电路的抗辐射加固技术上,对MEMS微敏感结构的辐照退化机理还缺乏深入的认识。由于MEMS微敏感结构和测试电路必须工作在一起,目前研究的难点在于如何准确地辨别出MEMS敏感结构在整表中所贡献的辐照退化量占比,并基于微纳测量的方法辨析出其辐照退化机理。针对该问题,本文首先开发出了一种针对MEMS器件分部件的辐照退化测量技术,成功提取出MEMS敏感结构所产生的辐照退化量;然后采用专门制备的对照MEMS芯片和电学测试的方法来对其退化机理进行研究。测量结果发现:MEMS敏感结构的辐照退化并不来自于寄生电容层的充电效应或各类电阻参数变化效应,而主要来自于界面薄氧化层的充电效应。这些界面层俘获的电荷会对MEMS可动质量块产生一个附加的静电力从而导致MEMS加速度计的输出漂移。综上,本文基于微纳测量的手段明确推断出了MEMS敏感结构在电离辐照条件下的退化机理,为后续的MEMS器件抗辐射加固改进提供了重要的技术方向指导。Radiation tolerant Micro Electro Mechanical System(MEMS)accelerometers are widely used in aerospace vehicles and nuclear industry.The reported researches are mostly concentrated on radiation hardness of MEMS devices'detecting circuits,while the radiation degradation mechanism of MEMS sensing part is still not well understood.Since MEMS device's micro-sensing part and detecting circuit must operate together,it is challenging to accurately distinguish the attributed degradation ratio of micro-sensing part when operating in the whole device,and acquire its radiation degradation mechanism by using micro and nano measuring techniques.To settle this issue,a radiation degradation measuring technique regarding to MEMS discrete parts is developed,and the radiation degradation attributed to MEMS sensing part is successfully extracted.Then,specifically fabricated MEMS contrast chips and electrical measuring techniques are utilized to study its radiation degradation mechanism.It is found that the radiation degradation attributed to MEMS sensing part is resulting from charging effect of the interface thin oxide layer,rather than charging effect of the parasite capacitor or changes of different resistor parameters.These trapped charges in the interface layer will produce an external electrostatic force on the movable proof mass,and then induce the output drift of MEMS accelerometer.In conclusion,this research experimentally infers a clear understanding of the degradation mechanism of MEMS sensing part under ionizing radiation environment,and it shows useful guidance on the future radiation hardness design of MEMS devices.

关 键 词：微机电系统(MEMS) 电容式加速度计 电离辐照退化 微敏感结构 

分 类 号：TN307[电子电信—物理电子学]