Comparison of damage growth and recovery in α-Al 2O 3 implanted with vanadium ions

Damage growth and recovery behavior are compared in (0001) α-Al ₂O ₃ samples implanted with ⁵¹V ⁺ at low temperatures and room temperature (RT) by employing RBS/channeling and RBS/ ¹⁶O(d,α) ¹⁴N nuclear reactions/channeling techniques. The on-site analysis of the damage growth process was performed using a dual beam analysis system at TIARA in JAERI/Takasaki. The damage growth at RT is not the simple accumulation of the same defect-profile at the initial stage of implantation. The damage introduction at low temperatures (36 and 100 K) induces an amorphous layer after 7.4 × 10 ¹⁴⁵¹V/cm ² implantation. The depth amorphized is at about 60% of the projected range and rather close to the peak position of the defect-profile at the initial stage in RT implantation. Regrowth of the amorphous layer is caused more easily in heavily implanted sapphire. The redistribution of implanted ⁵¹V atoms into the surface results in the coherent precipitation of vanadium oxide. The samples implanted at RT, which are crystalline even after the heavier implantation, change into mixed oxide after annealing by the preferential distortion of the oxygen sublattice.