Identification and Passivation of D-Center in 4H-SiC: A First-Principles Study

Abstract

As a deep acceptor defect in 4H-SiC, the D-center related to boron impurities has attracted much attention. However, there are still some disagreements regarding the origin of the D-center, as well as a lack of sufficient understanding of the related optical transitions and carrier capture processes. In this work, based on first-principles calculations, the optoelectronic properties of boron-related point defects in 4H-SiC is systematically investigated, and the passivation of hydrogen on B_C defects is also evaluated. The calculated 0/−1 transition levels of substitutional defect B_C are very close to the activation energies of the D-center observed in experiments. Furthermore, the photoluminescence (PL) peak positions and non-radiative hole capture cross-section of B_C defects calculated are all in good agreement with the experimental values of the D-center. This confirms that the substitutional defects B_C are responsible for the D-center in 4H-SiC. These calculation results reveal that the hydrogen atom in 4H-SiC prefers to combine with the B_C defects and to passivate the deep acceptor level within the bandgap in 4H-SiC by forming the B_C-H complex. This work effectively identifies and passivates the D-center in 4H-SiC, providing valuable insights for improving the performance of various semiconductor materials affected by deep defects.