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