Simultaneous Charge Carrier Density Mapping of SiC Epilayers and Substrates with Terahertz TDS

Silicon carbide is a highly interesting semiconductor with applications in power electronics and high-temperature environments making it both an already established and yet a still promising material. Electronic devices are typically composed of multiple layers of doped semiconductor materials. Therefore, a fast and non-destructive measurement method for the doping density is desirable. We present theoretical calculations and performed measurements using an ECOPS system to determine the charge carrier density of both doped epilayers and the substrate of 4H-SiC samples with charge carrier densities of the respective epilayer in the range of 7∙10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">15</sup> cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> and 1.5∙10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</sup> cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup>.