INSITU DC SPUTTERED HIGH-TC Y-BA-CU-O FILMS

Superconducting thin films of Y-Ba-Cu-O were fabricated in-situ by a dc-magnetron sputtering technique. The magnetron gun was designed to give a well defined plasma and a low operating voltage. Transition temperatures, Tc, of up to 85 K (R = 0) were measured for films deposited on Al203, SrTiO3 and MgO substrates using 1:15 oxygen to argon sputtering gas at 0.4 mbar pressure. A higher substrate temperature (670 °C) was needed to obtain an optimal Tc film on sapphire than on magnesium oxide or strontium titanate. Critical current densities of up to 105 A/cm2 at 4.2 K were registered for microbridges etched into films deposited on sapphire and up to 5.105 A/cm2 for those on magnesium oxide substrates. © 1990.