Effects of ion irradiation on chemical and mechanical properties of magnetron sputtered amorphous SiOC

Amorphous silicon oxycarbide (SiOC) films, fabricated by magnetron sputtering, were irradiated at room temperature with 3.5 MeV Fe ions to damage levels of 10, 20, and 50 displacements per atom (dpa). Irradiation-induced changes in the nature of the atomic bonds were studied using Raman spectroscopy and X-ray photoelectron spectroscopy. The chemical composition of the surfaces of the films remained relatively unchanged after ion irradiation. Surface topography of the films was studied by atomic force microscopy and it was found that ordered topographic patterns were formed on the surface of the irradiated films. Deformation behavior of the films was studied by a combination of nanoscratch experiments and in-situ scanning probe microscopy. No signs of cracks or chipping were observed around the scratches on the as-deposited and irradiated films. Furthermore, microindentation experiments with a Vickers indenter were performed on selected films and the impressions were studied by scanning electron microscopy. The film irradiated to 20 dpa showed an increased resistance to indentation cracking compared to the as-deposited film. The study demonstrates that amorphous SiOC, with desirable structural stability and mechanical properties, can be a promising candidate for irradiation tolerant materials.