X-ray diffraction studies of silicon implanted with high-energy erbium ions

Silicon crystals after implantation of erbium ions with energies in the range 0.8–2.0 MeV and doses in the range 1×1012–1×1014 cm−2 have been studied by two-and three-crystal x-ray diffraction. Three types of two-crystal reflection curves are observed. They correspond to different structural states of the implanted layers. At moderate doses (1×1012–1×1013 cm−2) a positive strain is observed, due to the formation of secondary radiation defects of interstitial type. An increase of the implantation dose is accompanied by the formation of an amorphous layer separating the bulk layer and a thin monocrystalline surface layer. At an implantation dose of 1×1014 cm−2 the monocrystalline surface layer is completely amorphized. Parameters of the implantation layers are determined. A model of the transformation of structural damage is discussed.