Plasma interaction processes during the pulsed laser deposition of superconducting thin films

Superconducting YBa2Cu3O7−x thin film growth by electron cyclotron resonance plasma-assisted pulsed laser ablation is studied. Resistivity and X-ray diffraction measurements were employed in analyzing plasma induced reaction processes during both the deposition and cooling stages of film preparation. It is demonstrated that the crystal structure is determined by the oxygen kinetics during the deposition process while the superconducting phase is formed through enhanced plasma oxidation during the cooling stage. Direct and glancing incidence plasma irradiation of the thin films surface was carried out. Under direct oxygen plasma irradiation, varying the average ion energy between 18 and 8 eV leads to a direct correlation between the ion energy and the resulting thin film crystal structure. Oxygen ion induced lattice defects and damage are identified as the limiting factor in producing high quality superconducting thin films at low substrate temperatures.