Wide-range Resistivity Characterization of Semiconductors with Terahertz Time-Domain Spectroscopy

Although the possibility of measuring the electrical properties of semiconductors with terahertz time-domain spectroscopy has been demonstrated early in the development of this measurement technique [1], it is not yet used on an industrial scale despite its advantage of being a non-destructive and non-contact method. Based on the Drude model, we present an analysis on the range of resistivities of doped silicon the method is applicable to, ranging roughly from 10^-3 Ωcm to 10² Ωcm [2]. For this purpose, commercially available samples covering the whole resistivity range were investigated. We compare the results to four-point probe reference measurements and show the possibility to image the spatial resistivity distribution by X-Y-scanning of whole wafers.