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The refractory nature of BaTiO3 leads to limited densification and grain growth for films processed at low temperatures and a modest nonlinear dielectric response due to a marked sensitivity to physical scale and material quality. Adding liquid-forming sintering aids, common in bulk ceramics, to thin films enhances mass transport, leading to enhanced grain growth at lower temperatures. This work explores the effectiveness of a sputtered CuO buffer layer with BaO-B2O3 (BBO) fluxes to engineer the microstructure of BaTiO3 films. Grain size and homogeneity increase in the presence of even a ~1 nm CuO layer. In general, grain size increases from 75 to 370 nm with an addition of 2.2% BBO and 8 nm CuO. Room temperature capacitance in fluxed films increases by a factor of 5 over pure films, and ferroelectric phase transitions are clearly observable in dielectric measurements. CuO-BBO proves effective on (0001) Al2O3 and (100) MgO substrates, although all microstructures are notably finer for the latter. [ABSTRACT FROM AUTHOR]

A process suitable for preparing metal-insulator-metal thin film capacitors with submicron insulating layers and top electrodes with cm-scale dimensions is presented. Most importantly, this process does not require sophisticated deposition equipment or a clean room environment. The key to large area yield is co-firing the insulator film with a non-dewetting electrode during the dielectric crystallization/densification anneal. We propose a mechanism of electrode dewetting during the high temperature anneal where the metal laterally retreats from geometric asperities that compromise the integrity of the insulating layer. This behavior is driven by surface energy minimization, which promotes metal migration away from the regions of high curvature. This methodology is not material specific, and only requires a top electrode with a large contact angle to the dielectric in question. Using this technique, functional thin film capacitors with 2.5 cm lateral dimensions and 1 µm dielectric thicknesses can be routinely prepared. [ABSTRACT FROM AUTHOR]