Solubility and diffusion of chromium in 4H-SiC

The solubility and diffusivity of Cr atoms in 4H-SiC epilayers are investigated. The formation energy of 4H-SiC containing Cr has been calculated by first-principles calculation. Si sites have been found to be more stable than C sites or interstitial sites for Cr atoms owing to the lower formation energy. The solubility estimated from the formation energy coincides with the saturated Cr concentration in SiC crystals grown by solution growth. The diffusivity of implanted Cr atoms (located at interstitial sites) was not affected by the charge states of Cr atoms and/or vacancies such as carbon vacancies and silicon vacancies, implying the interstitial diffusion of Cr atoms.