Batch production of large-area double-sidedYBa2Cu3O7−δ thin films by DC magnetron sputtering

Abstract

Using a novel DC magnetron sputtering system, high qualityYBa2Cu3O7−δ (YBCO) thin films were deposited on both sides of twelve pieces of 3-inchLaAlO3(00l) single crystal substrates in one batch. This sputtering system has a rotatable disc sample holder withthe LaAlO3 substrates being positioned in the middle of upper and lower YBCO targets. These twosputter guns are arranged to simultaneously deposit YBCO thin films on both sides of thesubstrate. The rotatable sample holder is an important approach to large scale depositionof high quality YBCO thin films. In this manner, the sputtered species can diffuse wellaround the substrates during one rotation cycle. Furthermore, the anode is installed in theinner of rotatable disc sample holder to avoid negative ion bombardment. Thus, a gooduniformity over the whole area for all the films has been realized. The full-width athalf-maximum (FWHM) values of the (005) rocking curves typically range from0.49° to0.56°. The superconducting critical temperatures fall in the range of89–90 K and the critical current densities are between 3.75 and4.0 MA cm−2 at 77 K. The microwavesurface resistance, RS (77 K, 10 GHz), of the YBCO thin films range typically from 0.56 to0.71 mΩ, which make these films suitable for microwave applications.