Contactless methods of conductivity and sheet resistance measurement for semiconductors, conductors and superconductors

Contactless methods of conductivity measurement are becoming increasingly important due to the progress being made in materials technology and the development of new materials intended for use in the electronics industry, including graphene, GaN and SiC. Despite the fact that they are conducting materials, some of them, like GaN and SiC, cannot be measured with the conventional four-point probe technique. Contactless measurement techniques offer fast and non-destructive methods to measure such materials. Selection of the appropriate method from the available techniques makes it possible to measure materials over a resistivity range of more than 20 decades, from 10(-9) to 10(12) Omega cm. This review gives an overview of the history of conductivity measurement, describes contactless measurement methods and discusses the most recent achievements in the field. Direct current, radio frequency, microwave and time domain measurement techniques are discussed in this review paper.