Effects of co-implanted oxygen or aluminum atoms on hydrogen migration and damage structure in multiple-beam irradiated Al2O3

Depth profiles of implanted H atoms were measured for single crystalline Al2O3 samples irradiated at 923 K with dual or triple beams of 0.25 MeV H-, 0.6 MeV He-, 2.4 MeV O-ions or 2.6 MeV Al-ions. The peaks occur at 1.55 and 1.45 μm in the depth profiles measured for the H + Al dual beam irradiation and H + O dual beam case, respectively. The ratio of the peak areas is over 4, which is much larger than the implanted H atom ratio of 1.1, indicating that implanted Al atoms suppress the mobility of H atoms. However, the ratio becomes almost 1 between the triple beam samples with H + He + O-ions and with H + He + Al-ions at comparable doses. The fact demonstrates that implanted He atoms overwhelm the effects of the implanted self-cation/anion excess atoms on the migration behaviors of implanted hydrogen and radiation produced point defects, with the resulting sluggish cavity growth observed.