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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 2MeV Se+ ions and 1MeV 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 5×103cm-2. The representative roughness values evaluated from the reflectometric measurements was 2.3±0.1nm for the substrates and less than 1.4±0.1nm for the epitaxial layers. A significantly higher damage level in the case of 2MeV Se+ ions in comparison with 1MeV 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.

The presently studied substrates for manufacturing freestanding silicon epitaxial layers contained two porous layers with different porosities. The upper layers of significantly lower porosity after annealing provided smooth surfaces for deposition of epitaxial layers and the deeper layers of greater porosity enabling easier exfoliation epitaxial foil. The layered structures have been studied by means of synchrotron diffraction topography and by recording of rocking curves from small local area. The most effective method of revealing defects in freestanding exfoliated layers were Bragg-case projection topographs and ‘zebra’ pattern monochromatic beam topographs providing a map of sample curvature. The samples have been additionally examined by means of high-resolution diffractometry and reflectometry.The porous layers without epitaxial deposition provided strong narrow maximum at low angle side of the substrate maximum common for both of the porous layers. The most probable effect of the deposition of epitaxial layer is the decrease of lattice parameter in the upper layer with lower porosity, which provided the maxima in the diffraction curves located on low angle side of the substrate maximum. The topographic investigations revealed some defects in deposited epitaxial layers, connected with some irregularities of the annealed porous layer. Very characteristic common defects were large caverns, overgrown in the epitaxial process with the diameters of several tenths of micrometers and defects (possibly the overgrown submicron caverns), associated with some bundles of dislocations resolved in the topographs. In layers of large thickness, the characteristic long black and white stripes along have also been observed, which most probably were stacking faults with dislocation loops.

Creation and transformation of defects in single crystalline (001) oriented Si-Ge with about 5.6 at. % Ge content, containing oxygen interstitials, O i's, at 9x1017cm-3 level, were investigated, after processing for 5 h at up to 1400 K (HT) under Ar pressure to 1.1 GPa (HP), by X-ray, synchrotron, infrared and photoluminescence methods. To create nucleation centres for Oi's precipitation, some samples were pre-annealed for 10 h at 1000 K under 105 Pa. HT-HP treatment at 1230/1400 K results in improved sample homogeneity and crystallographic perfection. HT-HP induced changes in Si-Ge are related mainly to HP-stimulated diffusivity of Ge. © (2011) Trans Tech Publications, Switzerland.

Defect structure of Czochralski grown silicon (Cz-Si) with nitrogen admixture, cN ≤ 5 × 1014 cm-3 (Cz-Si:N), annealed for up to 10 h at 1270-1400 K under hydrostatic Ar pressure ≤ 1.1 GPa, was investigated by synchrotron diffraction topography (HASYLAB, Germany), X-ray reciprocal space mapping, and infrared spectroscopy. Extended defects were not detected in Cz-Si:N processed at up to 1270 K. Such defects were created, however, in Cz-Si:N pre-annealed at 923 K and next processed at 1270 K or in as-grown Cz-Si:N processed at 1400 K. Investigation of temperature-pressure effects in nitrogen-doped silicon contributes to the understanding of defect formation in Cz-Si:N.

Defect structure of Czochralski grown (1 1 1) oriented silicon single crystals (Cz-Si), irradiated with fast neutrons (energy 5 MeV, dose 5×1016 cm-2) and annealed at up to 1400 K, also under hydrostatic Ar pressure equal to 1.1 GPa, has been investigated by high-resolution X-ray diffraction and synchrotron topography at HASY Laboratory. The annealing, especially at 1270 and 1400 K, results in precipitation of interstitial oxygen and creation of extended defects. A thermally induced oxygen precipitation at high temperatures-pressures in neutron-irradiated Cz-Si reveals the irradiation-related history of investigated samples. © 2009 Elsevier Ltd. All rights reserved.