With the growing demand for efficient power electronics, SiC-based devices are progressively becoming more relevant. In contrast to established methods such as the mercury capacitance-voltage technique, terahertz spectroscopy promises a contactless characterization. In this work, we simultaneously determine the charge carrier density of SiC epilayers and their substrates in a single measurement over a wide range of about 8x10^(15)$ cm^(-3) to 4x10^(18) cm^(-3) using time-domain spectroscopy in a reflection geometry. Furthermore, inhomogeneities in the samples are detected by mapping the determined charge carrier densities over the whole wafer. Additional theoretical calculations confirm these results and provide thickness-dependent information on the doping range of 4H-SiC, in which terahertz time-domain spectroscopy is capable of determining the charge carrier density.
@article{arxiv.2506.14945,
title = {Simultaneous Charge Carrier Density Mapping of SiC Epilayers and Substrates with Terahertz Time-Domain Spectroscopy},
author = {Joshua Hennig and Jens Klier and Stefan Duran and Kuei-Shen Hsu and Jan Beyer and Christian Roeder and Franziska C. Beyer and Nadine Schueler and Nico Vieweg and Katja Dutzi and Georg von Freymann and Daniel Molter},
journal= {arXiv preprint arXiv:2506.14945},
year = {2025}
}