Solid solubility and site preference of Ti in 3C- and 6H-SiC

Abstract

Ti is a background impurity in SiC due to its presence in the graphite parts of the SiC production furnace, and it has large impacts on the electrical and magnetic performance of SiC. Herein, the solid solubilities of Ti in 3C- and 6H-SiC were measured at the SiC–TiSi2 thermodynamic equilibrium, and the values of the enthalpy and entropy of dissolution for Ti in 3C- and 6H-SiC were estimated through thermodynamic analysis, which were also confirmed using the formation energy calculation of defects. The soft X-ray emission (SXE) lines of Ti-Lℓ for Ti-doped 3C- and 6H-SiC were explained by the calculated hole transition energies (HTEs) between the L1 and M3 levels in different possible defects, experimentally indicating that Ti prefers the substitution of the Si-site in both 3C- and 6H-SiC. Additionally, the zero-phonon line (ZPL) calculation provided a possible explanation for the origin of the ZPLs in the photoluminescence (PL) spectra of the Ti in 6H-SiC.