Study On The Formation Of Micro-Particle By Ion Implantation Method In α-Al₂O₃ Crystal

The studies on color centers defects in α-Al₂O₃ crystal is one of hot issues nowadays. The studies on the formation of micro-particles in crystal by using ion implantation with selecting implanting parameter, crystal orientation and thermal annealing process are very novel. Systematic studies on the formation of micro-particles of Copper in α-Al₂O₃ crystal with ion implantation followed by annealing in reducing atmosphere has not been reported. In this paper, the foundation of α-Al₂O₃ material and concept of color center are introduced first, and the basic theory of ion implantation is also discussed. And report on the experiment results of Cu⁺ ion implanted α-Al₂O₃ is presented. The main works and some conclusions are given as follows:1. Specimens of single crystal α-Al₂O₃ with different orientations were implanted by Cu⁺ with a dose of 5 ×10¹⁶ ions /cm² and energies from 350 to 380keV at different temperatures, followed annealed in reducing atmosphere at different temperatures. 2.Ion range and irradiation damage in α-Al₂O₃ material due to Cu⁺ ion implantationare given according to the TRIM procedure.3.There is a strong absorption at ultraviolet-visible light area for different samples.With Gaussian fitting and luminescence analyses, it is found that there are anionpoint defects, such as F, F⁺-type centers formed in the samples.4.Optical absorption measurements for samples prepared under different conditionsshow that the intensity is higher when implantation temperature is lower. Thisindicates that higher number of color defects existed at lower implantation temperature by using ion implantation.5.Color centers defects can be effectively eliminated by annealing based on an absorption measurement. It is found that the tendency in reduction of absorption intensity seems the same, this means that similar types point defects formed in a -AI2O3 crystal by Cu+ ion implantation and followed annealing under different conditions. The color centers defects seem basically eliminated by annealing at temperature of above 1000 °C.6.Many well-distributed sub-micrometer particles in the surface of the annealed a -AI2O3 specimens can be observed by SEM morphology. The size of these particles is greatly dependent on annealing conditions, especially annealing temperature. It is expected that the particles what we need, such as nanometer particles, can be formed in a -AI2O3 crystal at proper annealing temperature.