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The implantations were performed in 4H silicon carbide homoepitaxial layers deposited on (00.1) substrates with 8° offcut, and reference 4H-SiC substrates. The 2 MeV Se+ ions and 1 MeV Al+ ions were implanted with four fluences subsequently increased by the factor of 4-5×. The samples were studied by means of X-ray diffraction topography, high-resolution diffractometry, specular X-ray reflectometry, and Rutherford backscattering spectrometry\channeling method. The dislocation density in the samples evaluated from the diffraction topographs did not exceed 5 × 103 cm−2. The representative roughness values evaluated from the reflectometric measurements was 2.3 ± 0.1 nm for the substrates and less than 1.4 ± 0.1 nm for the epitaxial layers. A significantly higher damage level in the case of 2 MeV Se+ ions in comparison with 1 MeV Al+ ion and a linear increase of the strain with the fluence was indicated, but the highest doses of selenium ions caused the amorphization of the implanted layer. It was also possible to obtain a good fitting of the theoretical and experimental diffraction curves approximating the strain profiles by the distribution of the point defects calculated with the SRIM 2008 code. It was confirmed that the maximum coming from surface damages observed in channeling spectra of the virgin substrate wafers was significantly higher than in the case of epitaxial layers. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Undoped 4H silicon carbide epitaxial layers were deposited by means of CVD method with growth rates of 2 μm/h, 5 μm/h and 11 μm/h at 1540 °C on n-doped 8°, 4° and 0° off-cut 4H-SiC (00 · 1) substrates. The structural defects were studied before and after growth of the epitaxial layers by means of conventional Lang topography, synchrotron white beam and monochromatic beam topography and by means of X-ray specular reflectometry. The topographic investigations confirmed the continuation of the dislocations in the epitaxial deposit on the 8° and 4° off-cut substrates without new extended defects. The important difference occurred in the surface roughness of the epitaxial layers, which increased for higher growth rates. The epitaxial layers grown on 0° off-cut substrates at analogous condition contained usually other SiC polytypes, but the influence of the growth rate on the distribution of the polytypes was observed. [ABSTRACT FROM AUTHOR]

The numerical simulation has been applied for studying of Bragg-case section topographic images of dislocation and rod-like inclusions. The validity of simple approximation of extinction contrast was confirmed in the case of screw dislocations in silicon carbide crystals. A procedure for approximate calculation of the strain field of rod-like inclusion was constructed, consisting of adding the contributions from a very large number of point-like inclusions uniformly distributed inside the assumed volume of the inclusion. The procedure ensured a reasonable similarity between the simulated topographs and experimental Bragg-case section topographic images of some pipe-formed cavities in silicon carbide crystals. The method is useful for some other materials, e.g. it enabled to compute realistic simulation of plane-wave topographs of the rod-like inclusions in YAG. [ABSTRACT FROM AUTHOR]

X-ray reflectometric and diffraction topographic methods were applied for examination of 4H and 6H silicon carbide substrates finished with various regimes, as well as, silicon carbide epitaxial layers. The investigations indicated a very good quality of the substrate surfaces finished with the process established at the Institute of Electronic Materials Technology, which provided the surface roughness σ = 0:55 ± 0:07 nm for 4H-SiC wafers. These values were better than those of substrate wafers offered by many commercial producers. The surface roughness was decreased during the initial high temperature etching to σ = 0:22 ± 0:07 nm. A relatively good structural quality was confirmed in the case of 4H epitaxial wafers deposited on the substrates prepared from the crystals manufactured at the IEMT, with the 8° off-cut from the main (001) plane. [ABSTRACT FROM AUTHOR]