Interdiffusion between Sputtered MgO Films and Sapphire Substrates
Single crystalline αAl2O3 (sapphire) is a useful substrate material for a variety of thin film applications because of its inertness to processing chemicals and most film materials and the availability of high purity single crystalline substrates at reasonable size and cost. However, for films of the high temperature superconducting (HTS) oxides such as YBa2Cu3 O7−x (YBCO) grown directly on sapphire, there is a degradation in HTS properties occurring when deposition or subsequent annealing is carried out at high temperatures. In the early studies1 of YBCO on sapphire, the films were annealed at temperatures in the range of 850°–1000°C where interaction with sapphire was appreciable. More recent work2 has emphasized processing at temperatures as low as 400°C which significantly reduces but does not eliminate substrate-film interactions.
KeywordsHigh Temperature Superconducting Spinel Formation Spinel Layer Profilometer Measurement High Temperature Superconducting Film
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