Damage evolution and recovery on both Si and C sublattices in Al-implanted 4H–SiC studied by Rutherford backscattering spectroscopy and nuclear reaction analysis

Abstract

Damage evolution and subsequent recovery in 4H–SiC epitaxial layers irradiated with 1.1 MeV Al22+ molecular ions at 150 K to ion fluences from 1.5×1013 to 2.25×1014 Al cm−2 were studied by Rutherford backscattering spectroscopy (RBS) and C12(d,p)13C nuclear reaction analysis (NRA) using a 0.94 MeV deuterium (D+) beam in channeling geometry. Disorder on both the Si and C sublattices was measured simultaneously from the RBS scattering and NRA reaction yields. The relative disorder on both sublattices follows a nonlinear dependence on ion fluence that is consistent with a model based on simple defect accumulation and a direct-impact, defect-stimulated process for amorphization. At low ion fluences, the relative disorder on the C sublattice is higher than that on the Si sublattice. Isochronal annealing up to 870 K revealed the existence of three distinct recovery stages at ∼350, 520, and 650 K for low to intermediate damage levels. In highly damaged samples, where a buried amorphous layer is produced, the onset of a fourth recovery stage appears above 800 K. Similar recovery behaviors on both the Si and C sublattices suggests some coupling of recovery processes for Si and C defects.