Investigation Of Amorphous Oxide Thin Film Preparation Using Solution Deposition Planarization

The second generation YBCO high temperature superconductor(HTS) wires have broad application prospects in high voltage field for the advantage of its lower cost.Ion-beam assisted deposition(IBAD) biaxial texture magnesium oxide route severs as a main steam approach to obtain high-performance YBCO coated conductor. However,high quality IBAD-MgO film required substrates surface root square roughness less than 2 nm on 5 μm×5 μm areas. In this paper, chemical solution deposition planarization(SDP) serves as the main method for coating amorphous oxide thin films on Hastelloy substrates to decrease the surface root square roughness; besides a new stable precursor solution formula is discovered and research about ‘edge effort’ is did.Improve the roll-to roll coating machine whose efficiency of operations is 12 times of original machine. 20 hours is needed to deposit films on 100 m-long substrates.Factors which including the solvent, solute and additive affected the stability of precursor solution was studied. The finial stability of precursor solution is 3 days under the experimental condition; 2 weeks in simple static storage.Amorphous oxide thin film was deposited by SDP method on Hastelloy substrates surface. Factors including the temperature of rapid heat treatment process, precursor solution concentration, proportion of diethanolamine(DEA) and diethylenetriamine(DETA) which affected the roughness of amorphous oxide film surface and the homogeneity of amorphous oxide film was studied. Having a higher proportion of DEA was helpful for fabricating high homogeneity HTS wires. The final RMS roughness of amorphous oxide film surface was 1.192 nm on 20 μm×20 μm areas by SDP process.Fabricate 100m-length SDP amorphous oxide buffer film on Hastelloy substrates with RMS roughness below 2 nm; Fabricate 50m-length IBAD-MgO film on these substrates with in-plane texture of 4°-7°, out-plane texture of 2°-5°; Fabricate10m-length YBCO film by MOCVD with the critical current densities of 2.8 MA/cm2 at77 K.Because of the surface tension of precursor solution, the cracking on amorphous film edge appeared in SDP process. Three methods were tried to solve this question.‘Ensconcing the edge’ and decreasing surface tension work well. Besides, through studying the temperature of rapid heat treatment process and precursor solution concentration, appropriate process condition was found within 10 mm/s dipping speed.The final RMS roughness of amorphous oxide film surface was 1.738 nm on 5 μm×5μm areas.