Effects of plasma on the growth conditions of Y1Ba2Cu3O7-δ thin films in dc sputtering

Y1Ba2Cu3O7-delta (YBCO) films have been grown using hollow cathode do sputtering with various conditions. The effects of plasma conditions on the film qualities and the deposition rates have been studied in detail. To prevent the ion flux from reducing the film quality, it should be less than similar to2 x 10(-2) mA cm(-2) with a deposition rate of 1-2 nm min(-1). When the distance from the substrate to the target is very large or the discharge power is very small, the ion flux is sufficiently small. However, in the latter case the films are quite degraded, while there are no degradations for the films of the former case. Our experiments have revealed that this is due to the large differences in the densities of oxygen radicals for the two cases. The insufficient oxidation causing the degradations corresponds with the small Cu2p(3/2) satellite peaks of x-ray photoemission spectroscopy and the losses of Cu content. The deposition rates are much enhanced by decreased gas pressures, increased flow rates of gas and discharge power.