Multiaxial channeling study of disorder accumulation and recovery in gold-irradiated 6H-SiC -: art. no. 125206

Single crystal 6H-SiC has been irradiated 60 degrees off normal with 2 MeV Au2+ ions at 300 K to fluences of 0.029, 0.058, and 0.12 ions/nm(2), which produced relatively tow 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], [1 (1) over bar 02], and [10 (1) over bar1] 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 (1 (1) over bar 02) and [10 (1) over bar1], the disorder accumulation is larger and increases sublinearly with dose. Furthermore, a higher level of C disorder than Si disorder is observed along the [1 (1) over bar 02] and [10 (1) over bar1] 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 nn for this range of ion fluences. A steady accumulation of small displacements due to lattice stress is observed along the [10 (1) over bar1] axis, and a detectable reduction of the lattice stress perpendicular to the [0001] axis occurs at 0.12 Au2+/nm(2). There is only a moderate recovery of disorder, produced at and below 0.058 Au2+/nm(2), during thermal annealing at 570 K; more significant recovery is observed for 0.12 Au2+/nm(2) along both the [0001] and [1 (1) over bar 02] axes.