| A spatial composition spread approach was developed to explore the Bi 2Sr2Y(1--x )CaxOy (0≤x≤1)(Bi-2212) and the La(2--x)Sr xCuO4 (0≤x≤0.18)(La-214) cuprate systems. Using targets produced on-site, a series of depositions (approximately 75) were made by DC and RF magnetron sputtering to produce films with a linearly varying composition. Various conditions were tested to produce the best quality Bi-2212 and La-214 films.;From the Throughput calculations, the La-214 system was determined to be a more favorable system to study. Initial results from the La-214 system demonstrated the ability to produce a uniform phase across the entire deposition range, and this has been confirmed in recent measurements by another member (Mehran Saadat) of the group.;Overall many of the problems associated with depositing cuprate thin-films were overcome, and a simple, yet effective model, was developed to determine which multi-element targets would be suitable for our method.;High pressure depositions with a -20 V substrate bias effectively reduced an oxygen resputtering problem, but the resultant film was still rich in Bi and deficient in both Sr and Ca. 'These deficiencies led to phase impurity in the crystallized films. A comprehensive study on the deposition conditions highlighted a problem with using multi-element targets containing both Bi and Ca. Using a modified thermalized gas model, we defined a parameter called the Throughput, to help quantify the experimental trends. Both the Throughput calculations and the experimental data suggested that low pressure depositions would increase both the Sr and Ca concentrations. Low pressure depositions increased the Sr and Ca concentrations in the film. However, even with a substrate bias the film composition was not uniform due to resputtering. The variation of the film composition, caused by the resputtering, again results in a multi-phase film. |
