An economical route for production of high-quality YSZ buffer layers using the ECONO™ process (invited)

A new scalable and economical process has been developed to produce high-quality YSZ buffer layers on metal and alloy RABiTS. Current densities of 1 MA/cm(2) were achieved reproducibly on 0.3 mum-thick YBa2Cu3O7-delta, layers deposited on the YSZ buffer using PLD with an intermediate similar to20 mm ceria layer. The buffer process essentially involves depositing a similar to200 nm-thick epitaxial yttrium zirconium nitride directly on RABiTS, with subsequent conversion to a similar to300 nm-thick epitaxial yttria stabilized zirconia film via a simple oxidation step. The new process is termed ECONOTM, for Epitaxial Conversion to Oxide via Nitride Oxidation, and is also potentially useful for developing oxide epitaxial templates on non-oxide substrates (e.g., silicon or GaAs) for a broad range of device applications. The key advantage of this approach is that it avoids interference from substrate oxidation during epitaxial growth. For coated conductors, it eliminates both the need for an oxide seed layer and the need for a sulfur superstructure. In addition, the deposition of nitrides by reactive sputtering can be performed at much higher rates relative to oxides and the resulting YSZ films are dense and relatively defect-free. A description of the process and the associated conversion mechanism will be discussed.