Crystallization Atmosphere and Substrate Effects on the Phase and Texture of Chemical Solution Deposited Strontium Niobate Thin Films

Strontium niobate (Sr:Nb  =  1:1) thin films were prepared via chemical solution deposition on (001)‐oriented SrTiO₃, (001)_p‐oriented LaAlO₃, (0001)‐oriented sapphire, and polycrystalline alumina substrates. Crystallization in oxygen at 1000°C yielded Sr₂Nb₂O₇ films on all substrates with strong (010) orientation. Films on LaAlO₃ and SrTiO₃ single‐crystal substrates possessed a small amount of preferred in‐plane orientation, whereas films prepared on sapphire and polycrystalline alumina substrates were fiber textured. Films crystallized at 900°C in a low oxygen atmosphere (~10 ^{? 21} atm pO₂) formed a randomly oriented polycrystalline perovskite, SrNbO_3?δ on all substrates. A similar set of films crystallized at 900°C at a slightly higher oxygen partial pressure (~10^?15 atm pO₂) was comprised of Sr₂Nb₂O₇ and SrNbO_3?δ phases, exposing the dependence of phase formation on oxygen partial pressure. When subjected to a high‐temperature anneal in oxygen, the SrNbO_3?δ phase is shown to transform into Sr₂Nb₂O₇, however, Sr₂Nb₂O₇ did not significantly reverse transform into SrNbO_3?δ after annealing in low oxygen partial pressure atmospheres.