Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Semiconductor Substrates II: Structure, Epitaxy, Growth
O 17.4: Vortrag
Montag, 18. März 2024, 15:45–16:00, MA 144
In-situ analysis of phase transitions in ultrathin nickel silicides by time-of-flight medium energy ion scattering — •Carolin Frank1, Kevin Vomschee1, Radek Holeňák2, Eleni Ntemou2, and Daniel Primetzhofer2 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Duisburg, Germany — 2Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
We present first results obtained during the commissioning phase of recent upgrades to the Time-of-Flight Medium Energy Ion Scattering (ToF-MEIS) set-up at Uppsala University: A new UHV sample preparation chamber enables growth of thin films with a high precision in thickness by deposition from electron beam evaporators. We focus on calibration of the growth rate, in-situ deposition of thin nickel films on silicon and subsequent ToF-MEIS analysis of these films regarding phase transitions. Prior to deposition of nickel, the silicon substrates were treated ex-situ with hydrofluoric acid and annealed. To study the phase transition from the nickel layer deposited on silicon to epitaxial nickel silicide step-by-step, the samples were subsequently annealed up to 1500 K by an electron impact heater. During the stepwise annealing process, the transition to a well-ordered cubic nickel disilicide phase was found at 648 K. 2D scattering maps enable the analysis of intensity distributions of backscattered ions for selected energies. Since each of these energies corresponds to different chemical elements and - for a specific element signal - to specific depths within the sample, the epitaxy of the nickel silicide films due to blocking effects is verified.
Keywords: Time-of-flight medium energy ion scattering; Thin film growth; Phase transitions; Nickel silicide