Ta-ion implantation induced by a high-intensity laser for plasma diagnostics and target preparation

The present work is focused on the implantation of Ta ions into silicon substrates covered by a silicon dioxide layer 50–300nm thick. The implantation is achieved using sub-nanosecond pulsed laser ablation (1015W/cm2) with the objective of accelerating non-equilibrium plasma ions. The accelerated Ta ions are implanted into the exposed silicon substrates at energies of approximately 20keV per charge state. By changing a few variables in the laser pulse, it is possible to control the kinetic energy, the yield and the angular distribution of the emitted ions. Rutherford Back-Scattering analysis was performed using 2.0MeV He+ as the probe ions to determine the elemental depth profiles and the chemical composition of the laser-implanted substrates. The depth distributions of the implanted Ta ions were compared to SRIM 2012 simulations. The evaluated results of energy distribution were compared with online techniques, such as Ion Collectors (IC) and an Ion Energy Analyser (IEA), for a detailed identification of the produced ion species and their energy-to-charge ratios (M/z). Moreover, XPS (X-ray Photon Spectroscopy) and AFM (Atomic Force Microscopy) analyses were carried out to obtain information on the surface morphology and the chemical composition of the modified implanted layers, as these features are important for further application of such structures.