Comparative study of annealed neon-, argon-, and krypton-ion implantation damage in silicon

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Abstract
Comparative annealing studies were carried out upon Si layers implanted with Ne+, Ar+, and Kr+ ions. Ion doses were in the range 6×1014/cm2–6×1015/cm2, and ion energies were chosen so that the matrix damage had approximately the same depth for each ion type. Annealing was carried out in a N2/dilute O2 ambient or in vacuum at 600, 900, or 1100 °C. Implanted layer structures were studied using electron‐microscope and ion‐backscattering techniques. The orientation of the Si substrate and ion‐beam heating effects were found to be important in determining layer‐annealing behavior. The latter depended weakly, if at all, upon the nature of the annealing ambient. Layer recrystallization was studied as a function of implanted ion type and dose, and the effects of inert gases trapped in the Si lattice were examined. The suitability of implantations for device gettering applications were considered. Crystallographic defects produced by annealing ranged from polycrystals and microtwins to simple dislocation networks. Faceted gas bubbles invariably occurred in annealed layers, and their geometry gave information regarding low‐energy planes in Si. Electron diffraction and He+‐ion channeling effects produced by twins in recrystallized layers have also been examined.