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

为适应纳米技术发展的需要，研制了一种能在纳米尺度上测量纳米材料和纳米器件电性能的微波原子力显微镜。通过建立微波与原子力显微镜技术相结合的新系统，实现了同时测量材料表面形貌和电性能的能力。得到的结果如下：1。微波AFM探针的设计通过分析微波在探针内的传播特性，结合AFM探针的形状和尺寸，设计了一种能在探针内有效传播微波的波导。确定了微波AFM探针最合适的结构。为了抑制微波在探针中传播的衰减，采用了GaAs晶片作为探针的衬底。采用湿法蚀刻技术，成功制备了具有理想结构的GaAs原子力显微镜探针。通过蒸发GaAs AFM探针上下表面的Au膜，完成了微波AFM探针波导的制备。采用FIB法制备了探针尖端波导的开放式结构。成功制备了微波原子力显微镜探针。将研制成功的微波原子力显微镜探针、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。材料电性能的定量评价利用不同电导率的硅片样品，从微波响应与样品电导率之间的关系建立了材料电导率的定量评价模型。实现了一种定量评价材料小面积电性能的方法。

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.