Dislocations in 4H silicon carbide

Abstract

Owning 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 the applications of 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 high density of dislocations is one of the most important bottlenecks for advancing the device 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 wafers and epitaxial layers are introduced. The generation, evolution and annihilation of dislocations during the single-crystals 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 device performance and reliability 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 manipulation of dislocations in 4H-SiC.

Probing charge traps at the 2D semiconductor/dielectric interface

“…The density of interface trap states for various technologies 55–58 is shown in Fig. 1b, highlighting around two orders of magnitude higher D it at the interfaces of emerging technologies like 2D semiconductors when compared to the Si/SiO 2 interface.…”

“…(b) Interface trap densities of various semiconductor-dielectric interfaces. [55][56][57][58] (c) Surface defect density of various materials. [58][59][60][61][62][63][64][65] The defect densities of bulk semiconductors were extracted by the etch pit method, and white STM was used for WS 2 .…”

“…far away from the Fermi level are either occupied or empty and do not affect the charge dynamics and device characteristics. 44,54 The density of interface trap states for various technologies [55][56][57][58] is shown in Fig. 1b, highlighting around two orders of magnitude higher D it at the interfaces of emerging technologies like 2D semiconductors when compared to the Si/SiO 2 interface.…”

Nucleation of Threading Dislocations in 4H-SiC at Early Physical-Vapor-Transport Growth Stage

“…During the physical-vapor-transport (PVT) growth of 4H-SiC single crystals, TDs are formed under the thermal stress induced by the temperature gradient, as well as the misfit stress introduced by secondary precipitates, two-dimensional islands, polymorphs, and inclusions. ,, Synchrotron X-ray topography (XRT) observations demonstrate that most TDs are generated at the initial stage of crystal growth as a result of growth condition discontinuities, such as temperature profile, C/Si ratio, and doping concentrations. , TDs are also found to replicate from TDs in the seed crystal . Furthermore, the conversion from other kinds of defects to TDs is another important generation source of TDs during the single-crystal growth of 4H-SiC.…”

Role of the Growth Facet on the Generation and Expansion of Stacking Faults in PVT-Grown n-Type 4H-SiC Single-Crystal Boules

“…4H silicon carbide (4H-SiC) is a promising wide-bandgap semiconductor that has shown great potential in high-power and high-frequency electronics as well as quantum information technologies. , Physical-vapor-transport (PVT) technology has successfully realized commercialization in the growth of 4H-SiC single-crystal boules. , During the PVT growth of 4H-SiC single-crystal boules, the generation and expansion of stacking faults (SFs) pose a risk for severe degradation of the quality of 4H-SiC single crystals because the SF energy of 4H-SiC is as low as 14.7 ± 2.5 mJ/m 2 . SFs in 4H-SiC serve as the nucleation center of threading dislocations, micropipes, and secondary polymorphs .…”