Comparison between the different implantation orders in H⁺ and He⁺ coimplantation

H⁺ and He⁺ were implanted into single crystals in different orders (H⁺ first or He⁺ first). Subsequently, the samples were annealed at different temperatures from 200°C to 450°C for 1 h. Cross sectional transmission electron microscopy, Rutherford backscattering spectrometry and channelling, elastic recoil detection were employed to characterize the defects and the distribution of H and He in the samples. Furthermore, the positron traps introduced by ion implantation and annealing were characterized by slow positron annihilation spectroscopy. Both orders in the coimplantation of H and He have the ability to decreases the total implantation dose after annealing. No bubbles or voids but cracks and platelets, were observed by cross sectional transmission electron microscopy. The different implantation orders affect the density of interstitial atoms and positron traps.