Origin of a fourfold symmetric (0 0 0 6) Bragg diffraction intensity in φ-scan mode on a 6H-SiC crystal

Abstract

The quality of silicon carbide (SiC), when used as a substrate, has profound effects on the growth of the homo/hetero-epitaxial film on it. Here, a fourfold symmetric (0006) x-ray diffraction intensity in a φ-scan mode is found to have nothing to do with the deformation of wafers or the existence of mosaic domains, regardless of whether it is a double-sided polished 6H-SiC wafer or a thick 6H-SiC slice. The experimental results show that both the diffraction intensity and its full width at half maximum as a function of the azimuth angle φ exhibit the features of four peaks and four valleys regularly. By measuring the bending of the diffraction planes along the azimuth angles at the peaks and valleys, saddle-shaped deformed (0 0 0 1) atomic planes of the 6H-SiC in macroscopic scale are hypothesized. Based on the hypothesis, a model analysis of the diffraction intensity matched well with the observed anisotropic symmetric x-ray diffraction in a 6H-SiC single crystal.