Oxygen tracer diffusion through BaF2 and MgO overcoats on YBa2Cu3O7−Δ

Abstract

The movement of oxygen through MgO and BaF2 overcoats on YBa2Cu3O7−Δ has been studied using 18O tracer diffusion techniques. By analyzing the 18O and 16O signals from secondary-ion mass spectrometry depth profiles, the motion of small concentrations of oxygen in both insulating and oxygenated hosts has been tracked. BaF2 was found to be <m1;37p>transparent to oxygen diffusion while MgO blocked its motion during 10 min 500–600 °C anneals. Uncovered YBa2Cu3O7−Δ films were also found to exchange up to 90% of their oxygen during similar anneals. These results have important ramifications for reoxygenation steps during device fabrications.