Using a novel DC magnetron sputtering system, high quality
YBa2Cu3O7−δ
(YBCO) thin films were deposited on both sides of twelve pieces of 3-inch
LaAlO3(00l)
single crystal substrates in one batch. This sputtering system has a rotatable disc sample holder with
the LaAlO3
substrates being positioned in the middle of upper and lower YBCO targets. These two
sputter guns are arranged to simultaneously deposit YBCO thin films on both sides of the
substrate. The rotatable sample holder is an important approach to large scale deposition
of high quality YBCO thin films. In this manner, the sputtered species can diffuse well
around the substrates during one rotation cycle. Furthermore, the anode is installed in the
inner of rotatable disc sample holder to avoid negative ion bombardment. Thus, a good
uniformity over the whole area for all the films has been realized. The full-width at
half-maximum (FWHM) values of the (005) rocking curves typically range from
0.49° to
0.56°. The superconducting critical temperatures fall in the range of
89–90 K and the critical current densities are between 3.75 and
4.0 MA cm−2 at 77 K. The microwave
surface resistance, RS
(77 K, 10 GHz), of the YBCO thin films range typically from 0.56 to
0.71 mΩ, which make these films suitable for microwave applications.