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Semiconducting silicon carbide (4H-SiC) exhibits characteristics of high hardness, notable brittleness, and excellent chemical stability. The commonly employed technique for achieving an ultra-smooth and flat surface is chemical mechanical polishing (CMP), which is utilized to process the 4H-SiC surface. Wet oxidation, as an important process of chemical-mechanical polishing of single-crystal 4H-SiC, directly affects the rate and surface quality of CMP. This paper provides a comprehensive overview of the current research status of wet oxidation of single-crystal 4H-SiC. It discusses the oxidants used in the wet oxidation of 4H-SiC, such as KMnO4, H2O2, K2S2O8. Based on this, it further summarizes commonly employed oxidation-enhancement methods, including photocatalytic-assisted oxidation, electrochemical oxidation, and Fenton reaction. The mechanism of wet oxidation of single-crystal 4H-SiC is analyzed from the aspect of theoretical calculation, and the future research direction of wet oxidation of 4H-SiC is proposed. [ABSTRACT FROM AUTHOR]

4H silicon carbide (4H-SiC) substrate wafers without surface / subsurface damages and low surface roughness are ideal substrates for the development of power electronics and radio frequency (RF) microwave devices, which hold great promise in applications of new energy, rail transportation, smart grid and 5G communication. The processing of 4H-SiC substrate wafers includes slicing, grinding, lapping, polishing and cleaning. However, the surface damages ( SDs) and subsurface damages (SSDs) introduced during the processing of 4H-SiC substrates affects the properties of 4H-SiC substrates and epitaxial layers, and thus the performance and reliability of devices based on 4H-SiC. This paper focuses on the formation and removal mechanisms of SDs / SSDs during the processing of 4H-SiC substrate wafers. Based on the detection method of SDs / SSDs, the morphologies and characterization approaches of SDs / SSDs are reviewed. Finally, three commonly used technologies for the removal SDs / SSDs, along with their technical advantages, development challenges and trends, are briefly discussed. [ABSTRACT FROM AUTHOR]

As one of the most important steps in machine processing of 4H-silicon carbide (4H-SiC) wafers, lapping exerts an important impact on the quality of 4H-SiC substrate wafers. In this paper, the effects of diamond abrasive morphology and dispersion medium on the material removal rate and surface parameters of 4H-SiC wafers were investigated. Based on the contact between diamond abrasive and 4H-SiC wafer surface during lapping process, a simple wafer material removal rate model was derived. It is found that the abrasive morphology significantly affects the material removal rate of 4H-SiC substrate wafers, the higher the material removal rate, the smaller the total thickness variation (TTV) is obtained for 4H-SiC substrate wafers. Due to the anisotropy of C-face and Si-face of 4H-SiC, the material removal rate of C-face is higher than that of Siface. In terms of effect of the dispersion medium, the Zeta potential absolute value of the water-based slurry is high, and the abrasive is evenly dispersed. It is beneficial to control the disc temperature during the lapping process due to the large thermal conductivity of water. The Zeta potential absolute value of the glycol-based slurry is small, and the abrasive is prone to agglomeration. As the abrasive cutting depth deepens in lapping process, the material removal rate of 4H-SiC wafer increases, and the maximum value of scratch depth also aggravates accordingly. [ABSTRACT FROM AUTHOR]

Wide bandgap semiconductors are ideal materials for the application of high power density, high frequency and low- loss power electronic devices, owning to the advantages of wide bandgap, high electron saturation velocity, and high breakdown field. Attributed to the high thermal conductivity, high chemical stability and high heat resistance of silicon carbide (SiC), epitaxy of wide bandgap semiconductors on SiC is promising to exploit the advantages of wide bandgap semiconductors and improve the performance of wide bandgap semiconductor devices. Benefiting from the continuous quality-improvement and cost-reduction of SiC substrates, wide bandgap semiconductors grown on SiC substrates are ushering in an explosive growth. Epitaxy of high quality wide bandgap semiconductors on SiC substrates is critical to the performance and reliability of wide bandgap semiconductor devices. This paper summarizes the recent progress obtained on epitaxial growth of SiC, gallium nitride (GaN) and gallium oxide (Ga2O3) on SiC substrates. In addition, the prospective of wide bandgap semiconductors grown on SiC substrates for high-performance electronics are prospected. [ABSTRACT FROM AUTHOR]

SiC is considered as one of the more promising semiconductor materials because of its advantages such as wide band gap, high critical breakdown field strength, high thermal conductivity and high carrier saturation mobility. In recent years, physical vapor transport (PVT) method has made great breakthroughs in the preparation of large size and high quality SiC single crystal substrates, further promoting the application of SiC in the field of high voltage, high frequency and high temperature electronic devices. SiC powder is the raw material of PVT method to grow SiC single crystal. The purity of powder will directly affect the impurity content of SiC single crystal, so as to affect the electrical properties of SiC single crystal. The growth of high quality semi-insulating SiC single crystal is directly limited by the content of N element in the SiC powder. Therefore, the synthesis of high-purity SiC powder is the key to the growth of high-quality SiC single crystal by PVT method. This paper mainly introduces the synthesis methods and research status of high purity SiC powder, the advantages and disadvantages of gas-phase and solid-phase synthesis of high purity SiC powders are reviewed, and the development direction of high purity SiC powders synthesis in the future is put forward. [ABSTRACT FROM AUTHOR]