Study of thermal recrystallisation in Si implanted by 0.4-MeV heavy ions

A Si crystal layer on SiO₂/Si was implanted using 0.4-MeV Kr⁺, Ag⁺, and Au⁺ at ion fluences of 0.5 × 10¹⁵ to 5.0 × 10¹⁵ cm⁻². Subsequent annealing was performed at temperatures of 450° and 800° for 1 hour. The structural modification in a Si crystal influences ion beam channelling phenomena; therefore, implanted and annealed samples were investigated by Rutherford backscattering spectrometry under channelling (RBS-C) conditions using an incident beam of 2-MeV He⁺ from a 3-MV Tandetron in random or in aligned directions. The depth profiles of the implanted atoms and the dislocated Si atom depth profiles in the Si layer were extracted directly from the RBS measurement. The damage accumulation and changes in the crystallographic structure before and after annealing were studied by X-ray diffraction (XRD) analysis. Lattice parameters in modified silicon layers determined by XRD were discussed in connection to RBS-C findings showing the crystalline structure modification depending on ion implantation and annealing parameters.