First-Principles Study of Charged Point Defects in 4H-SiC: Accurate Formation Energies, Trap Levels, and Beyond

To accurately investigate the properties of charged defects in 4H-SiC, large-scale ab initio simulations are carried out with the QuantumATK atomic-scale modeling platform by Synopsys. For a variety of charged defects, calculations of formation energies and trap levels are performed using density functional theory with the hybrid HSE06 XC-functional and linear combination of atomic orbitals basis sets. Agreement of the computed trap levels of carbon vacancies with experimentally observed levels validates the accuracy and reliability of the simulation. With the nudged elastic band method, diffusion properties are also computed and analyzed. Finally, by calculating the phonon density of states in each system using a moment tensor potential trained for 4H-SiC, the vibrational correction is made to obtain the equilibrium concentration of each charged defect at finite temperatures.