Nondestructive high spatial resolution imaging with a 60 GHz near-field scanning millimeter-wave microscope

We demonstrate a nondestructive millimeter-wave surface imaging technique using a near-field scanning millimeter-wave microscope (NSMM) with a resonant standard waveguide probe at an operation frequency f=60 GHz. A chemically etched metallic probe tip was coupled to the resonant rectangular waveguide. By properly tuning the tunable resonator and the probe tip we could improve sensitivity and spatial resolution of the NSMM. By measuring the change of the quality factor in the near-field zone, near-field scanning millimeter-wave images of patterned metal films and YBa₂Cu₃O_y thin films were obtained with a spatial resolution better than 1 μm. We observed the dependence of the current density NSMM images of patterned indium tin oxide films on the bias currents. © 2004 American Institute of Physics.