Effect of various buffer layers for the large-scale atomic layer deposition integration of archetypical SrTiO3 thin film on silicon substrate

The integration of perovskite oxides on silicon remains a technological bottleneck, particularly for the growth of thin SrTiO3 (STO) films used as buffer or template layers for epitaxy. While Atomic Layer Deposition (ALD) offers scalability and conformality, achieving crystalline STO on silicon is hindered by low-temperature constraints and silicon diffusion during post-deposition annealing. This study explores STO growth via Direct Liquid Injection-ALD using Titanium Tetra-IsoPropoxide [Ti(O-iPr)4] and Strontium bis(2,2,6,6-tetramethyl-3,5-heptanedionate) (Sr(thd)2), with engineered buffer layers to enhance crystallization and suppress interdiffusion. We first investigate cationic stoichiometry control by adjusting the number of TiO2 and Sr-O sub-cycles. Scanning Transmission Electron Microscopy analysis confirms STO layer formation but reveals silicon diffusion that impedes crystallization. To address this, we introduce 10 nm-thick binary oxide layers (TiO2 and Sr-O) and [Ca2Nb3O10]− nanosheets (NNS) as diffusion barriers. A crystallized TiO2 layer further improves STO structural quality, while NNS promote [001]-oriented STO growth on silicon. These results demonstrate a viable route for large-area crystalline STO deposition on silicon, with implications for the integration of functional oxides requiring controlled orientation and crystallinity. The STO/NNS platform offers a scalable template for subsequent oxide growth, paving the way for multifunctional oxide electronics on silicon and other technologically relevant substrates.