Ion beam channeling study of cobalt implanted sapphire

Rutherford backscattering spectrometry combined with channeling and Transmission Electron Microscopy (TEM) were used for investigation of cobalt implanted single crystalline α-Al ₂O ₃. The energy of the cobalt ions was 150 keV with various doses. To get good crystalline quality after implantation, a thermal annealing at 1500°C for 1 hour was carried out. Angular scans were performed along different axes. We found that crystalline precipitates grew epitaxially into the hexagonal host crystal. The presence of precipitates was also proven by cross sectional TEM measurements that showed their typical diameter between 10-50 nm. Other than these precipitates no cobalt was found by energy dispersive spectroscopy.