Quantitative Study of Near-Field Microwave Microscopy: Application to Metrology of Dielectrics at Nanoscale

The scanning near-field microwave microscope was developed to quantitatively measure the local permittivity of materials at nanoscale. The microwave probe was designed based on a quartz tuning fork (TF) glued with the electrochemically etched metal wire. The sensitivity and signal-to-noise-ratio of the measurement were improved by a two-port interferometric matching circuit. By using a calibrating protocol and a near-field electrical tip-sample model, the local permittivity of the nano-film was determined from the calibrated capacitance images.