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Owing to the superior properties of the wide bandgap, high carrier mobility, high thermal conductivity and high stability, 4H silicon carbide (4H-SiC) holds great promise for applications in electrical vehicles, 5G communications, and new-energy systems. Although the industrialization of 150 mm 4H-SiC substrates and epitaxial layers has been successfully achieved, the existence of a high density of dislocations is one of the most severe bottlenecks for advancing the performance and reliability of 4H-SiC based high-power and high-frequency electronics. In this topical review, the classification and basic properties of dislocations in 4H-SiC are introduced. The generation, evolution, and annihilation of dislocations during the single-crystal growth of 4H-SiC boules, the processing of 4H-SiC wafers, as well as the homoepitaxy of 4H-SiC layers are systematically reviewed. The characterization and discrimination of dislocations in 4H-SiC are presented. The effect of dislocations on the electronic and optical properties of 4H-SiC wafers and epitaxial layers, as well as the role of dislocations on the performance and reliability of 4H-SiC based power devices are finally presented. This topical review provides insight into the fundamentals and evolution of dislocations in 4H-SiC, and is expected to provide inspiration for further control of dislocations in 4H-SiC. [ABSTRACT FROM AUTHOR]

Basal plane dislocations (BPDs) are one of the most harmful dislocations in 4H silicon carbide (4H-SiC). Understanding the nucleation of BPDs is the basis of reducing the density of BPDs in 4H-SiC. In this work, we investigate the nucleation mechanism of BPDs, as well as the effect of doping on the nucleation of BPDs in 4H-SiC using nanoindentation. It is found that the shear stress plays a dominant role in the nucleation of BPDs in undoped 4H-SiC. This indicates that the shear component of the thermal stress during the growth of 4H-SiC single crystals and that of the mechanical stress during the processing of 4H-SiC wafers both give rise to the nucleation of BPDs. Nitrogen (N) doping is found to facilitate the nucleation of BPDs and decrease the shear stress required for the nucleation of BPDs. In contrast, vanadium (V) doping hinders the nucleation of BPDs, which promotes the polymorph transition from 4H-SiC to 3C-SiC. [ABSTRACT FROM AUTHOR]