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THz Sheet Resistance Measurements on Semiconductor Layers in Reflection Geometry

Mr. Konstantin Wenzel1, Dr. Steffen Breuer1, Dr. Robert Kohlhaas1, Prof. Martin Schell1,2, Dr. Lars Liebermeister1
1Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Berlin, Germany. 2Technische Universität Berlin, Institut für Festkörperphysik, Berlin, Germany

Abstract

In this study, we determine the electrical properties of thin III/V semiconductor samples using terahertz reflection measurements. The samples under study were grown on indium phosphide (InP) substrates, and they exhibit a wide range of resistances from 5 Ω/sq to 3·104 Ω/sq. We find that the simple Tinkham Equation shows good agreement with the measurements and accurately describes the trend of the reflectivity for all the samples. This shows that THz TDS is a suitable tool for characterising III/V layers on InP substrates in this resistance range without physical contact.