Effects of substrate temperature and annealing temperature on the formation and properties of erbium silicide layers synthesized by high current Er ion implantation

Abstract

Ion beam synthesis of ErSi2−x by erbium implantation into Si wafers with a metal vapor vacuum arc (MEVVA) ion source has been performed and the effects of substrate temperature and annealing temperature on its properties have been investigated. The implantation was performed at an extraction voltage of 60 kV to ion doses ranging from 5×1016 to 2×1017 cm−2 with beam current densities from 3 to 26 μA/cm2 corresponding to substrate temperatures ranging from 85 to 245 °C. The characterization of the as-implanted and annealed samples was performed using Rutherford backscattering spectrometry, x-ray diffraction, atomic force microscopy, and electrical resistivity measurements. The results showed that ErSi2−x phase was directly formed by MEVVA implantation when the substrate temperature Ts⩾200 °C. For the samples synthesized at lower implantation temperatures, postimplantation annealing is necessary to achieve the formation of ErSi2−x. Direct measurements of the sputtering depth on masked implanted samples at various substrate temperatures showed that the sputtering yield increases with increasing temperature. The intensive sputtering and aggregation due to high substrate temperatures result in surface fractal patterns, in some cases, discontinuous layers, thus the high resistivity of the layers.