Dual Ion Assist Beam Processing of Magnesium Oxide Template Layers for 2nd Generation Coated Conductors

Abstract

Ion beam assisted deposition (IBAD) of magnesium oxide (MgO) has been shown to be a viable route for producing biaxially textured template films on flexible polycrystalline metal substrates for high-performance coated conductor development. We have refined the technique of IBAD by using a dual ion assist approach. Dual ion assist beam deposition (DIBAD) of MgO reduces the requirements for substrate surface finishing while maintaining comparable film quality (phi scan full-width at half-maximum values between 7 and 8deg). Furthermore, this adaptation of the IBAD process eliminates the degradation of MgO texture observed in IBAD MgO films deposited on silicon nitride. We have deposited films up to 50 nanometers thick without degradation of the in-plane texture. Increasing the MgO thickness increases the chemical stability of template layer and can eliminate the necessity for subsequent buffer layers or the application of the homoepitaxial MgO layer needed to stabilize the thin, conventional IBAD MgO layer. The initial performance of coated conductors made with DIBAD templates is quite promising.