Negative ion resputtering in Ta2Zn3O8 thin films

Thin films have been deposited by radio frequency magnetron sputtering from a stoichiometric Ta2Zn3O8 ceramic target (3ZnO+1Ta2O5). Negative ion resputtering effects have been observed in the stoichiometric Ta2Zn3O8 target and have been attributed to O− ion formation from primarily Ta–O bonds. Zinc deficient thin films were deposited as a result of the preferential resputtering of Zn versus Ta. The negative ion resputtering effects are exacerbated at higher powers and lower pressure. This observation is correlated to the oxygen ion transport through the dark space and the plasma, which ultimately controls the energy distribution of the oxygen particles that arrive at the substrate. Another ceramic target with excess ZnO (6ZnO+1Ta2O5) was also sputtered under similar conditions, however predominantly ZnO films were deposited. Finally, a mosaic ZnO–Ta target was sputtered, which resulted in stoichiometric and luminescent thin films.