EFFECT OF AN A-SI LAYER ON THE SUPERCONDUCTING PROPERTIES OF HIGH-T(C) YBCO-FILMS

Results of the deposition of a-Si onto YBa2Cu3O7-x thin films are repo rted. The silicon was grown by plasma enhanced chemical vapour deposit ion at low substrate temperature (300-degrees-C). With this deposition process the critical temperature of the super conductor remained almo st constant but the critical current was reduced by nearly one order i n magnitude. X-ray 2theta-scans exhibited highly oriented films and SE M studies showed that the a-Si film smoothed the YBa2Cu3O7-x surface w ith no observable crack formation. An interface layer with a maximum w idth of 30 nm was deduced from ESCA depth profiles.