The structure of sapphire implanted with nitrogen at room temperature and 1000 deg. C

The structure of N-implanted sapphire (single crystal α-Al2O3) has been studied using Rutherford backscattering-ion channeling spectroscopy (RBS-C), transmission electron microscopy (TEM) and optical absorption. Specimens having the c-axis normal to the optically polished surface were implanted with 3x1016 N/cm2 (150 keV) at room temperature and 1000 deg. C. Little residual disorder was observed in the RBS-C spectra for the RT samples. A band of bubbles or voids (diameters 1-10 nm) extending from about 75 to 300 nm below the surface was observed in cross-sectioned TEM specimens. The disorder was greater in the 1000 deg. C sample and the TEM examination indicated the presence of extended defects lying parallel to the c-planes