T/CASAS 014-2021 Determination of the bending of the SiC substrate planar base using high-resolution X-ray diffraction

Scope

Scope: This document specifies a method for characterizing the base plane curvature of 6H and 4H silicon carbide single-crystal substrates using high-resolution X-ray diffraction. This document is applicable to the characterization of base plane curvature in 6H and 4H silicon carbide single-crystal substrates with a (0001) plane or a (0001) plane-oriented crystal orientation; Main technical content: Silicon carbide (SiC) has high critical breakdown field strength, high thermal conductivity, high electron saturation drift velocity, excellent mechanical properties, and physical and chemical stability, making it suitable for the fabrication of high-temperature and high-power devices. When using silicon carbide as a substrate for growing device structures, the quality of the substrate plays a decisive role in the quality of the epitaxial layer. Large-sized silicon carbide single crystals often exhibit a phenomenon where the diffraction peak position of the base plane wobbles and shifts with the change of the diffraction position of the single crystal diameter. This movement of the diffraction peak position is caused by base plane curvature. Due to the existence of base plane curvature, the c-axis of the edge position of the homogeneous epitaxial or heterogeneous epitaxial layer deviates from the center c-axis, affecting the uniformity and reliability of subsequent device fabrication processes. Only by understanding the characteristics of base plane curvature in silicon carbide single-crystal substrates can we gain a deeper understanding of the causes of base plane curvature, provide directions for optimizing single-crystal growth conditions, and ultimately improve single-crystal quality. Therefore, it is necessary to develop a method that can accurately and comprehensively characterize the base plane curvature of silicon carbide single crystals. At present, standards in China for characterizing the crystal plane curvature of silicon carbide single-crystal wafers by X-ra

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