基于电化学研磨的SPM钨探针制备方法研究

钨探针是扫描隧道显微镜(STM)常用探针之一。为了将钨探针应用于扫描探针显微镜(SPM)，根据钨探针的受力，通过理论分析确定了钨探针的理想轮廓：钨探针的直径变化应具有指数曲线。为了获得指数曲线轮廓、尖锐测头等良好特性的钨探针，分别提出并研究了改进的钨探针液面直流电化学研磨法和薄膜直流电化学研磨法。通过这两种电化学研磨法获得的探针以及通过传统的交流电化学研磨法获得的钨探针，分别在探针的形状、探针尖端曲率半径、表面质量、研磨速度、可复现性等多个方面进行了观察和比较。通过实验发现，除了研磨速度外，改进的液面直流电化学研磨法和薄膜直流电化学研磨法在其他各方面都优于交流电化学研磨法。

Research on Preparation Methods of Tungsten Probe for SPM Based on Electrochemical Polishing

Tungsten probe is one of the common probes used in scanning tunnel microscopy (STM). In order to applied tungsten probe to scanning probe microcopy (SPM), the ideal profile of the tungsten tip was determined through theoretical analysis according to its inner stress distribution: the diameter near zero at the apex of the tip should increase to the maximum diameter according to an exponential curve. In order to obtain tungsten tips with advantages such as exponential profile and sharp tip, two tungsten probe preparation techniques, of which one is an improved drop-off DC electrochemical polishing technique, and the other is a lamellae drop-off DC electrochemical polishing technique, were put forwards and studied. The tips fabricated respectively by these two kinds of techniques and traditional AC electrochemical polishing technique were observed and compared in many aspects such as tip shape, apex radius, surface quality, polishing speed and reproducibility. By the experimental observations, the improved drop-off DC electrochemical polishing technique and the lamellae drop-off DC electrochemical polishing technique are better than AC technique in the above aspects except polishing speed.