J. Phys. IV France 05 (1995) C5-365-C5-371
High Quality YBa2Cu3O7-x Superconducting Thin Films Grown by MOCVDC. Dubourdieu1, J.P. Sénateur2, O. Thomas1 and F. Weiss1
1 Laboratoire des Matériaux et du Génie Physique, Ecole Nationale Supérieure de Physique de Grenoble, URA 1109 du CNRS, BP. 46, 38402 St Martin d'Hères, France
2 Laboratoire MATOP. Faculté des Sciences et Techniques de St Jérôme. Av <ATTillisible> Normandie Niemen, 13397 Marseille, France
YBCO thin films have been grown by Metal Organic Chemical Vapour Deposition in a cold wall type reactor. The [MATH]-diketonates of yttrium, barium and copper are used as precursors. Films have been deposited on (001) MgO and (012) La AlO3 single crystalline substrates. The morphology is very dependant on the gas phase composition. Different partial pressures have been investigated. an increasing oxygen partial pressure - at a fixed deposition temperature - is found to increase the growth rate and to promote the grouwth of a-axis grains (grains with the c axis parallel to the substrate's surface). In our standard deposition conditions, Tsubstrate holder = 875°C, PTotal = 5 Torr, and PO2 = 2 Torr, high quality films are obtained, exhibiting [MATH] of the resistive transition) and [MATH] . A trilayer structure YBCO/Y2O3/YBCO (900 Å/100Å/900Å) has been grown on La AlO3 substrate, with the epitaxial relationship : <110> (001)YBCO // <100> or <010> (001)Y2O3. No misorientations have been found in the (a,b) plane. The trilayer exhibits a sharp superconducting transition ([MATH]), with Tc = 82.5 K, and Jc(77 K) - 106 A/cm2.
© EDP Sciences 1995