Contactless conductivity measurement for ITO nanolayers on AsGa substrats over a wide frequency range

Abstract : We report on the application of a new contactless method based on eddy currents with a view to characterizing some transport properties of a large range of semiconductors. The innovative approach of this work consists in measuring the impedance of the coil by reflectometry using a broadband multicarrier test signal. The device works well with silicon wafers with a constant conductivity over a wide frequency range. Because of their electrical conductivity and high optical transmittance in the visible and near-IR regions of electromagnetic spectrum, indium tin oxide (ITO) films have motivated great interests in experimental studies and technological applications. The estimation of their electrical conductivity is a key point to develop these devices. On this paper we show that the setup can be used for the frequency characterization of ITO and AsGa nanolayers wich exhibit a frequency dependent behavior. The low frequency measurement are found in agreement with the classical four point probe setup.