基于石墨烯的变刚度微结构研究

RESEARCH ON VARIABLE STIFFNESS MICROSTRUCTURE BASED ON GRAPHENE

刘师宇

11930456

硕士

材料工程

宋学锋

2021-05-19

2021-06-07

南方科技大学

深圳

人类对世界的探索离不开传感技术的发展，最典型的代表就是加速度传感器。目前的加速度传感器，主要有两大类，一类是大型科研检测设备，大型检测设备可以充分发挥结构精巧和灵敏度高的优势，探测出µg甚至ng重力加速度变化，可用于测量地表不同位置的重力加速度差异；另一类是以微纳加工为主的MEMS加速度传感器，这类传感器具有精密小巧，易于与其他电子设备集成的特点，目前主流的MEMS加速度传感器设计方案包括压电设计、容感设计、热感设计，但此类产品的灵敏度还无法与大型设备相比较。 隧穿式加速度传感器从原理上可以达到ng级别的测量精度，目前国际上仍无法做出该类器件的原因，是因为该类加速度传感器对于隧穿针尖的要求极高，电流从针尖通过会导致针尖的金属原子发生电迁移而使得针尖变形，器件失效，因此需要采用更为可靠的材料制造隧穿针尖及电容极板。石墨烯作为一种二维碳材料，是世界上最为坚硬稳定的物质之一，是用于制造隧穿加速度传感器针尖及电容极板的理想材料。石墨烯有三大明显优势，1.厚度薄容易获得较低的吸合电压；2.表面平整，可以避免电极板表面毛刺在极小间距下与另一极发生击穿；3.强度高、表面疏水可避免断裂和黏附等失效。 制作石墨烯隧穿传感器之前，需要有完整可靠的石墨烯微机电开关制造技术，并以此为基础，进一步探究，石墨烯悬臂梁在静电驱动的情况下的位移与变形情况，基于课题组之前的研究成果，本人对石墨烯的变刚度微结构进行进一步的研究。主要工作如下： (1) 石墨烯变刚度结构的建模与仿真分析 (2) 石墨烯变刚度悬臂结构制备 (3) 石墨烯变刚度MEMS结构表征测试 本课题研究提出一种变刚度石墨烯创新性结构，可以满足非工作时间防止悬臂撞击电极的同时，在工作期间可以精准控制悬臂位置的需求，为之后制作完整的隧穿型加速度传感器做进一步准备。

Human exploration of the world is inseparable from the development of sensing technology. The most typical representative is acceleration sensor. At present, there are mainly two types of accelerometers. One is large-scale scientific research equipment, which can detect µg or even ng gravity acceleration changes, and can be used to measure the difference of gravity acceleration at different positions on the surface by giving full play to its advantages of exquisite structure and high sensitivity. The other is MEMS accelerometers mainly based on micro-nano processing. This kind of sensor has the characteristics of precision, compact size, and portability. At present, MEMS accelerometers with mature technology mainly adopt piezoelectric, capacitive and thermal design methods, but the sensitivity of such products is not high and cannot be compared with large-scale equipment. The tunneling accelerometer can achieve ng-level measurement accuracy in principle. The reason why this kind of device cannot be made at present is that this kind of accelerometer requires extremely high tunneling tip. The passage of current from the tip would cause electromigration of the metal atoms of the tip and the tip deformation device to fail. Therefore, it is necessary to use more reliable materials to manufacture the tunneling tip and the capacitor plate. Graphene, as a two-dimensional carbon material, is one of the hardest and most stable substances in the world, and is an ideal material for manufacturing tunneling accelerometer tips and capacitor plates. Graphene has three obvious advantages: 1. Thin thickness is easy to obtain lower pull-in voltage; 2. The graphene surface is flat, which can prevent burrs on the electrode plate surface from breaking down with the other pole at a very small distance; 3. Graphene has high strength and hydrophobic surface, which can avoid failure such as fracture and adhesion. Before manufacturing graphene tunneling sensors, it is necessary to have a complete and reliable manufacturing technology of graphene MEMS switches. Therefore, it explores the displacement and deformation of graphene cantilever beam under electrostatic drive. In this paper, the variable stiffness microstructure of graphene is further studied. The main work is as follows. (1) Modeling and simulation analysis of graphene variable stiffness structure (2) Preparation of a graphene variable stiffness cantilever structure (3) Test of graphene variable stiffness MEMS structure characterization The research innovatively proposes a variable stiffness graphene structure, which can meet the requirements of preventing tip damage during non-working hours and accurately controlling tip position during working hours. What’s more, it paves the way for making a complete tunneling accelerometer later.

石墨烯 变刚度 静电驱动 建模仿真 制备表征

graphene variable stiffness electrostatic drive modeling and simulation preparation and characterization

中文

独立培养

南方科技大学

刘师宇. 基于石墨烯的变刚度微结构研究[D]. 深圳. 南方科技大学,2021.