The effect of zirconium implantation on the structure of sapphire

The effect of zirconium implantation on the structure of sapphire was investigated by 175keV Zr implantation at room temperature to a fluence of 4×1016ions/cm2 into sapphire single crystals. Samples were examined by several experimental techniques: Rutherford backscattering spectroscopy along a channeling direction (RBS-C), electron-energy loss spectroscopy (EELS), and Z-contrast images obtained in an aberration-corrected scanning transmission electron microscope. Range and deposited energy were simulated with SRIM-2008.04. The Z-contrast images from transmission electron microscope indicated: a near surface damaged layer ∼30nm thick, a subsurface region exhibiting “random” de-channeling ∼52nm thick, and a deeper damaged, crystalline zone ∼64nm thick. The RBS-C spectra confirmed the presence of these three regions. The two damaged regions contained high concentrations of as yet unresolved defect clusters. The intermediate region contained Zr-clusters embedded in an “amorphous” matrix that exhibited short-range order corresponding to γ-Al2O3, i.e., a defective spinel structure. The EELS measurements show that the amorphous region is deficient in oxygen.