Peculiarities in magnetron sputtering of YBCO epitaxial films for applications in superconductor electronics devices

We consider the main factors determining the growth of YBa$_2$Cu$_3$O$_{7-\delta}$ high-T c superconductor films during magnetron sputtering in the planar axial geometry. Special attention is paid to the increase of the growth rate of the films suitable for superconductor electronics devices. Magnetron sputtering is used for obtaining YBa$_2$Cu$_3$O$_{7-\delta}$ films with high structural and electrophysical characteristics for a growth rate up to 200 nm/h, which were used in constructing microwave disk resonators and long Josephson junctions on bicrystal substrates. The unloaded Q factor of cavities exceeds 80000 at a frequency of 7.1 GHz at a temperature of 77 K, which corresponds to the best results in this field. Josephson junction of length 50–350 $\mu$m are characterized by critical current density $j_c$ = 12–33 kA/cm$^2$ at $T$ = 77 K and $j_c$ = 93–230 kA/cm$^2$ at $T$ = 6 K in zero magnetic field. The characteristic voltage $I_cR_n$ is 0.8–1.96 mV.