Combinatorial synthesis and evaluation of epitaxial ferroelectric device libraries

Combinatorial libraries of parallel-plate capacitors, consisting of Pt and ${\mathrm{La}}_{\mathrm{0.5}}{\mathrm{Sr}}_{\mathrm{0.5}}{\mathrm{CoO}}_{\mathrm{3}}$ electrodes and a doped ${\mathrm{Ba}}_x{\mathrm{Sr}}_{\text{1−x}}{\mathrm{TiO}}_{\mathrm{3}}$ dielectric layer, have been fabricated and analyzed to systematically study the effects of dopants on device performance. Epitaxial heterostructure libraries with sharp interfaces were generated from amorphous layers on ${\mathrm{LaAlO}}_{\mathrm{3}}$ substrates. Two hundred and forty different host/dopant combinations were synthesized on a 1/2 in. by 1/2 in. substrate, with 23 capacitors for each combination. Addition of 1.5 mol % W was found to increase the figure of merit ${\mathrm{(\epsilon /I}}_{\mathrm{leak}})$ 220-fold and reduce the high-frequency (MHz and GHz) loss tangent by fourfold.