Carbon-related point defects on the 4H-SiC surface are essential for understanding the origin of defects at the SiO₂/SiC interface and improving the quality of epitaxial materials. In this work, a first principle calculation was carried out to study the structural and electronic properties of carbon antisite (C_Si), vacancy (V_C) and interstitial defects (C_i1, C_i2, C_i3 and C_i4) on the 4H-SiC (0001) surface. The optimized structures showed that interstitial defects except C_i2 caused the surface reconstruction of 4H-SiC. The variation in formation energies with chemical potentials of the carbon for all defects indicated that the C-rich condition was beneficial to the formation of C_Si, C_i1, C_i3 and C_i4, whereas the Si-rich condition was more favorable to V_C. We also observed that these defects except C_i4 generated the corresponding defect energy levels in the bandgap of 4H-SiC by calculating the density of states and local charge densities. Furthermore, the effects of defect coverage and lateral lattice strain on structural and electronic properties of these defects were provided.

4H-SiC表面上的碳相关点缺陷对于了解SiO ₂ /SiC界面缺陷的起源和提高外延材料的质量至关重要。在这项工作中，进行了第一性原理计算，以研究4H 上碳反位点 (C _Si )、空位 (V _C ) 和间隙缺陷 (C _i1、C _i2、C _i3和 C _i4 ) 的结构和电子特性。 -SiC (0001) 表面。优化后的结构表明除 C _{i2外的间隙缺陷}引起4H-SiC的表面重建。所有缺陷的形成能随碳的化学势的变化表明，富C条件有利于C _Si、C _i1、C _i3和C _i4的形成，而富Si条件更有利于V _C. _ 我们还观察到除了C _i4之外的这些缺陷通过计算态密度和局部电荷密度在4H-SiC的带隙中产生了相应的缺陷能级。此外，还提供了缺陷覆盖率和横向晶格应变对这些缺陷的结构和电子特性的影响。