ABSENCE OF NEGATIVE-ION EFFECTS DURING ON-AXIS SINGLE TARGET SPUTTER DEPOSITIONS OF Y-BA-CU-O THIN-FILMS ON SI (100)

Stoichiometric thin films of YBa2Cu3O 7-δ have been deposited on (100) silicon substrates by on-axis single target magnetron sputtering. The effect of oxygen resputtering was minimized through the use of much stronger than usual magnetic assemblies in the source. A magnet assembly incorporating NdB and NdFeB magnets produced a magnetic field above the target twice as large as the one produced by a standard SmCo magnet assembly. This allows for the use of lower operating voltages and a better electron racetrack confinement, resulting in little or no oxygen resputtering. We have obtained stoichiometric or near-stoichiometric films on silicon both by dc and rf magnetron techniques at a variety of sputtering pressures and target to substrate distances.