Scanning Microwave Microscopy:A Novel Tool for Nanoscale Microwave Imaging/Characterization
ABSTRACT :
The evolution of the sub-micron/ nano technology field scales down the electronic devices and improves the quality and performance of novel devices. The development of emerging technologies in the sub-micron scale include not only the development of technology to prepare materials in such sub-micron scale but also there should be suitable analytical and experimental tool to help us improving our knowledge in understanding the fundamental science behind the materials used for these devices. As most of our understanding of materials comes from studying the interaction of electromagnetic fields with matter, it is necessary to have a tool that can enable the fields to interact with the matter at nanoscale. Scanning Microwave Microscopy (SMM) or Near-field Microwave Microscopy (NFMM) is a novel and a new addition to the scanning probe microscopy technique and is related to the measurement of the materials response to microwave radiation on much lower length scales compared to the free space wavelength of the irradiated microwave wavelength. SMM integrates two well-known measurement tools, the scanning probe microscope (eg. AFM) for surface characterization andthe vector network analyser (VNA) for high-frequency signalmeasurements. The microscope allows for nanometre lateralresolution imaging, and the VNA provides high precisionimpedance and admittance measurements at broadband frequenciesfrom MHz to GHz, thus it enables nanoscale spatially resolved measurements of impedance variations at microwave frequencies. In this talk, the basic principles of Near-Field Microwave Microscopy will be reviewed with focus on the microandnano-scale resolution configurations for materialscience measurements. Results on nanoscale dopant profile, dielectricand magnetic measurements will be presented, with details onthe calibration protocols needed for quantitative estimationof the material properties. The future plans of implementing and using this novel tool for advanced materials characterization will be discussed.