Multiaxial channeling study of disorder accumulation and recovery in gold-irradiated6H−SiC

Single crystal $6H-\mathrm{SiC}$ has been irradiated 60° off normal with 2 MeV ${\mathrm{Au}}^{2+}$ ions at 300 K to fluences of 0.029, 0.058, and 0.12 ${\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{s}/\mathrm{n}\mathrm{m}}^2$, which produced relatively low damage levels. The disorder profiles as a function of ion fluence on both the Si and C sublattices have been determined simultaneously in situ using Rutherford backscattering and nuclear reaction analysis with 0.94 MeV $D^{+}$ ions in channeling geometry along the 〈0001〉, $〈11¯02〉,$ and $〈101¯1〉$ axes. Along the 〈0001〉 axis at these low doses, similar levels of Si and C disorder are observed, and the damage accumulation is linear with dose. However, along $〈11¯02〉$ and $〈101¯1〉,$ the disorder accumulation is larger and increases sublinearly with dose. Furthermore, a higher level of C disorder than Si disorder is observed along the $〈11¯02〉$ and $〈101¯1〉$ axes, which is consistent with a smaller threshold displacement energy on the C sublattice in SiC. The mean lattice displacement, perpendicular to each corresponding axis, ranges from 0.014 to 0.037 nm for this range of ion fluences. A steady accumulation of small displacements due to lattice stress is observed along the $〈101¯1〉$ axis, and a detectable reduction of the lattice stress perpendicular to the 〈0001〉 axis occurs at 0.12 ${\mathrm{Au}}^{2+}{/\mathrm{n}\mathrm{m}}^2.$ There is only a moderate recovery of disorder, produced at and below 0.058 ${\mathrm{Au}}^{2+}{/\mathrm{n}\mathrm{m}}^2,$ during thermal annealing at 570 K; more significant recovery is observed for 0.12 ${\mathrm{Au}}^{2+}{/\mathrm{n}\mathrm{m}}^2$ along both the 〈0001〉 and $〈11¯02〉$ axes.