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 SrTiO 3 , (001) p ‐oriented LaAlO 3 , (0001)‐oriented sapphire, and polycrystalline alumina substrates. Crystallization in oxygen at 1000°C yielded Sr 2 Nb 2 O 7 films on all substrates with strong (010) orientation. Films on LaAlO 3 and SrTiO 3 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 p O 2 ) 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 p O 2 ) was comprised of Sr 2 Nb 2 O 7 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 Sr 2 Nb 2 O 7 , however, Sr 2 Nb 2 O 7 did not significantly reverse transform into SrNbO 3−δ after annealing in low oxygen partial pressure atmospheres.