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

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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.