Reel-to-reel Deposition of Y2O3 Buffer Layer on Ni-W Metal Substrates by the RF-sputtering

Reel-to-reel deposition of Y2O3 has been performed on Ni-5%W metal substrates using the RF-sputtering method. The epitaxial orientation of Y2O3 buffer layers to the base bi-axially textured substrate was well identified using θ-2θ, out-of-plane (ω), and in-plane (φ) scans in X-ray diffraction analysis. The optimization of Y2O3 seed layers in reel-to-reel fashion were investigated varying the deposition temperature, sputtering power, and pressure for its significant roles for the following buffer stacks and superconducting layers. Y2O3 were all grown epitaxially on bi-axially textured metal substrates at 380 watts and 5 mTorr in the temperature range of 600-740 degree C with higher Y2O3 (400) intensities at ∼710 degree C. It was found that the ω values were 1-2 degree lower but the φ values were above 1 degree higher than that of Ni-W substrates. As the sputtering power increased from 340 to 380 watts, ω and φ values showed decreased tendency. Even in the small window of deposition pressure of 3-7 mTorr, the Y2O3 (400) intensities increased and ω and φ values were reduced as sputtering pressure increased.