Microwave Methods of Studying Semiconducting Materials

摘要

The normalized impedance transformation approach, which is a general procedure for the analysis of microwave reflection and cavity methods of measuring the properties of materials, is presented. The material, whose resistivity and permittivity are unknown, is regarded as one layer in an assembly of layers shaped to fit the cross-section of, and placed with its parallel interfaces normal to the axis of the cylindrical waveguide used in the measuring apparatus. Several of the methods suitable for determining semiconductor resistivity are analysed, and results are presented for specimen resistivities in the range 0.0001 to 10,000 ohm-cm and specimen thickness in the range 10 to 100,000,000 A. Bimodal waveguide methods of studying the properties of semiconducting materials are reviewed and the bimodal cavity method is selected for detailed consideration. Expressions for the propagation constants of circularly-polarized waves in semiconductor-filled bimodal waveguide subject to a longitudinal magnetic field are obtained. They are used in the application of the normalized impedance transformation approach to the analytical problem of relating the measurable properties of the bimodal cavity to the physical properties of the specimen under study. (Author)