Conformal deposition of amorphous TiO <i>x</i> in high-aspect-ratio trenches by atmospheric-pressure mist chemical vapor deposition

We demonstrate conformal deposition of amorphous TiOx films into high-aspect-ratio Si trenches by tubular furnace type atmospheric-pressure mist chemical vapor deposition (mist-CVD) using titanium diisopropoxide bis(acetylacetonate) [Ti(acac)2(OiPr)2] precursor dissolved in methanol solvent. Intermittent mist feeding, substrate positioning, and mesh electrode biasing yielded >90% step coverage in aspect ratio = 10–25 trenches at 200–300 °C. The resulting films were smooth (refractive index n ≈ 2.2 at 550 nm, RMS <0.61 nm). Thus, mist-CVD combines high uniformity and low cost with excellent conformality governed by droplet infiltration and electrostatic guidance, establishing it as a scalable technique for conformal metal oxide thin film deposition in high-aspect-ratio structures relevant to microelectronics and energy storage devices.