Development of Microwave Atomic Force Microscope and Quantitative Evaluation of Electrical Properties in Nano-Area

为满足纳米技术发展的需要，研制了一种能够在纳米尺度上测量纳米材料和纳米器件电学性质的微波原子力显微镜。通过建立一种结合微波和原子力显微镜技术的新系统，实现了对材料表面形貌和电学性质的同时测量。1.微波原子力显微镜探头的设计通过分析微波在探头中的传播，以及原子力显微镜探头的形状和尺寸，设计了一种能够在探头中有效传输微波的光波导。2.砷化镓原子力显微镜探头的制作为了抑制微波在探头中传播的衰减，采用了砷化镓晶片作为探头的衬底。3.微波原子力显微镜探头的研制通过在探头的顶面和底面蒸镀Au膜，引入了一种波导。通过FIB制作得到了探头尖端的开放式结构。将研制的微波原子力显微镜、原子力显微镜和网络分析仪相结合，实现了一种能同时测量材料表面形貌和电学性能的新型微波原子力显微镜。5.材料电学性能的定量评价以不同电导率的硅片样品为例，从微波响应与样品电导率之间的关系出发，建立了定量评价模型。实现了一种定量评价材料小区域电学性能的方法。

To satisfy the requirement of the development of nano-technology, a microwave atomic force microscope which can measure the electrical properties of nano-materials and nano-devices in nano-meter scale was developed. By establishing a new system combined with the microwave and atomic force microscope techniques, the capability to measure the surface topography and the electrical properties of materials simultaneously was realized. The obtained results are as follows.1.Design of microwave AFM probeBy analyzing the propagation of microwave in the probe, and the shape and dimensions of AFM probe, a waveguide which can propagate microwave in the probe effectively was designed. The most suitable structure of the microwave AFM probe was determined.2.Fabrication of GaAs AFM probeTo restrain the attenuation of microwave propagating in the probe, GaAs wafer was used as the substrate of the probe. Using wet etching technique, GaAs AFM probe having a desired structure was fabricated successfully.3.Completion of microwave AFM probeA waveguide was introduced by evaporating Au film on the top and bottom surfaces of the GaAs AFM probe. The open structure of the waveguide at the tip of the probe was obtained by using FIB fabrication. A microwave AFM probe was formed successfully.4.Construction of microwave atomic force microscopeThe developed microwave AFM probe, atomic force microscope, and network analyzer were combined, and a new microwave atomic force microscope which can simultaneously measure the surface topography and the electrical properties of materials was realized.5.Quantitative evaluation of electrical properties of materialsBy using silicon wafer samples having different electrical conductivities, quantitative evaluation model was built up from the relationship between the response of microwave and the conductivity of the samples. A quantitative method to evaluate the electrical properties of materials in small area was realized.