J. Phys. IV France 03 (1993) C3-321-C3-328
Preparation of YBa2Cu3O7 films by low pressure MOCVD using liquid solution sourcesF. WEISS1, K. FRÖHLICH2, R. HAASE1, M. LABEAU1, D. SELBMANN3, J.P. SENATEUR1 and O. THOMAS1
1 LMGP-ENSPG, CNRS URA 1109, BP. 46, 38402 Saint-Martin d'Hères, France
2 I.E.E., Slovak Academy of Sciences, Dubravska cesta 9, 842 39 Bratislava, Czechoslovakia
3 I.F.W., Dresden, Helmolzstr. 20, 8027 Dresden, Germany
A hybrid low pressure MOCVD process is described for reproducible preparation of superconducting thin films of YBa2Cu3O7. The process uses a single solution source of Y, Ba, and Cu [MATH]-diketonates dissolved in suitable organic solvents. This liquid precursor is atomized using an ultrasonic aerosol generator and transported as small droplets ( ≈ l μm) into a CVD reactor where solvent and precursor are first evaporated before deposition takes place at low pressure on heated substrates in a cold wall geometry. This process allows, with stable evaporation rates for all three precursors, to grow in-situ superconducting films with constant composition from film to film. Thin and thick films with high critical temperatures and critical currents have been obtained (Tc>80K, Jc>l04 A/cm2 at 77K in self field) which are highly c-axis oriented. Experimental details of this new process are described and the effects of different process parameters are studied in order to improve the quality of the deposited layers.
© EDP Sciences 1993