Ion implantation of the 4H SiC epitaxial layers and substrates with 2 MeV Se⁺ and 1 MeV Al⁺ ions

Abstract

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 × 10 3 cm À2 . 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.

Analysis of Strain in Ion Implanted 4H-SiC by Fringes Observed in Synchrotron X-Ray Topography

“…Fringe pattern and satellite peak analysis have been widely used for characterizing the strain gradient in the ion implanted materials [11,14]. If the separation of the fringes is approximated wider than 10", the conventional high-resolution X-ray diffractometry with monochromator can reveal such patterns.…”