Damage and thermal annealing of In + implanted a-axis sapphire

Abstract

Single crystal samples of 〈1 2 10〉α-Al 2O 3 were implanted with 100 keV and 360 keV indium ions to doses of 6 × 10 16ions/cm 2, 1 × 10 16ions/cm 2, and 3 × 10 16ions/cm 2, respectively, at room temperature (RT). The implanted samples were annealed isothermally in high purity argon ambient at 900°C, from 2 to 24 h. Rutherford Backscattering Spectrometry and Channelling (RBS-C) and Reflection High Energy Electron Diffraction (RHEED) have been used to study the depth distributions of lattice damage and impurity, as well as the annealing behavior. All three as-implanted samples do not show an amorphous layer, which indicated that the self-annealing is severe during In ion implantation of α-Al 2O 3 at RT. For the 100 keV ion implanted samples, In loss and formation of In 2O 3 were observed after 12 h annealing. The In ions are completely located in the interstitial sites for all samples annealed at 900°C for 12 h. For the higher energy (360 keV) implantation, single crystal is retained at the outermost surface in the as-implanted sample.