Noncontact characterization of sheet resistance of indium–tin-oxide thin films by using a near-field microwave microprobe

The sheet resistance of indium–tin-oxide (ITO) thin films with different microstructures and morphologies was measured by using a near-field scanning microwave microprobe (NSMM). The NSMM system was coupled to a dielectric resonator with a distance regulation system at an operating frequency f = 5.2–5.5 GHz. ITO thin films with different microstructures and morphology were characterized by X-ray diffraction and atomic force microscopy. As the sheet resistance increased, the intensity ratio of the (222) to the (400) diffraction peak increased and the surface roughness increased.