Electronic devices based on the high-temperature superconductor (YBCO) may deteriorate in the operating environment under the influence of moisture, atmospheric carbon dioxide and frequent thermal cycling. To avoid these impairments a passivation layer was developed which is deposited by polymerization of the silicon organic compound hexamethyldisilasane (HMDS-N) in a plasma enhanced chemical vapour deposition (PECVD) process. The 100 nm thin films exhibit excellent passivation properties which is confirmed by electrical transport measurements of passivated wide and 100 nm high YBCO lines and step edge Josephson junctions exposed to humidity and . No degradation in the critical parameters such as the critical current , the normal resistance and the flux-voltage modulation depth is observed on step edge dc-SQUIDs owing to the deposition of the passivation layer. Atomic force microscope (AFM) measurements show a smooth morphology of these layers without pinholes and an excellent coverage of the YBCO even at the edges of lines. Furthermore, the passivation layer can be used as an isolation and scratch protection between SQUIDs and thin-film flux transformers in flip-chip magnetometers.

We have fabricated thin-film flux transformers prepared from heteroepita~a~y grown, highly c-axis oriented azCu&/~fli03/YBazCu& -trilayers. Crossovers and vias well as complete test coiIs exhibit critical temperatures around 8% with critical current densities of j, = 1.5x106 Mcm2 investigations showed that only convex edges enable highly c-axis oriented films on the beveled edges with the CuO-planes aligning themsekes parallel to the substrate surface. The fabricated ffux transformers yield a gain of more than 43. To protect devices against their environment and prevent o~y~e n losses we have developed a passivation layer deposited ation of the silicon-organic compound in a plasma enhanced , The about 150nm thick tion properties without properties. The films can be used as the isolatim and scratch protection between thin-film flux transformers in flip-chip

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