Evaluation of electrical characterization methods for determining charge carrier and dopant concentration in silicon carbide

Knowledge of free charge carrier and dopant concentration is a prerequisite for the application of any semiconductor material. Silicon carbide is a wide bandgap semiconductor that has significantly different characteristics than the widely used materials silicon or gallium arsenide. A measurement setup was constructed to perform capacitance voltage and for comparison Hall measurements over a wide temperature range. A superconducting magnet system was modified to measure the Hall scattering factor. The capacitance voltage method is the most simple and therefore most common method, but can yield meaningless results if the tested material and test structure are not well understood. Capacitance voltage measurements on a variety of different samples are presented. Activation energies determined from Hall measurements of the most important n-type dopant, nitrogen, are larger than those determined by infrared absorption measurements in high quality 4H SiC epitaxial layers. The Hall scattering coefficient was measured in 4W and 6H epitaxial layers. The Hall scattering factor can explain some of the observed deviation. Common error sources in C-V measurements, series resistance and frequency dispersion effects by deep impurities are discussed.