Development of Rutile Titanium Oxide Thin Films as Battery Material Component Using Atomic Layer Deposition

Abstract

Herein, growth kinetics, crystal structure, and the uniformity of titanium oxide (TiO2) thin films prepared using atomic layer deposition (ALD) and plasma‐enhanced ALD (PE‐ALD) are studied. TiO2 thin films are grown using titanium tetrachloride (TiCl4), water, and oxygen precursors. Using ALD, TiO2 is grown in the temperature range of 270–310 °C thermally and in the range of 300–400 °C with PE‐ALD. In spite of the plasma process yielding better uniformity on planar structures, the optimized thermal process provides a remarkable conformal step coverage within deep trenches. In addition, the change in the crystal structure and phase transitions of TiO2 is presented herein. This is attempted at using TiO2 as a component material to grow lithium titanate (LTO) as an electrode material in solid‐state lithium‐ion batteries (LIBs). Thereby, different substrates are used. In comparison to the silicon (Si) substrate, silicon oxide (SiO2) and titanium nitride (TiN) lead to crystal phase transformation while annealing. Measurements are performed using in situ high‐temperature X‐ray diffraction (HT‐XRD). It is also shown that when TiN is sandwiched between TiO2 and the silicon substrate, the TiO2 thin film (25 nm) gradually changes from an anatase to a rutile structure.

Atomic Layer Deposition of Textured Li4Ti5O12: A High‐Power and Long‐Cycle Life Anode for Lithium‐Ion Thin‐Film Batteries

“…In general, the interface properties strongly influence the nucleation behavior, such as heterogeneous and homogeneous nucleation, and crystallization kinetics in thin films. [38][39][40][41] The surfaces of the amorphous SiO 2 and polycrystalline TiN substrates have different characteristics such as surface energy, termination chemistry, roughness, and local structure. [36,38,41] However, the nucleation behavior of Li 4 Ti 5 O 12 thin films was not yet explained in literature.…”

“…[38][39][40][41] The surfaces of the amorphous SiO 2 and polycrystalline TiN substrates have different characteristics such as surface energy, termination chemistry, roughness, and local structure. [36,38,41] However, the nucleation behavior of Li 4 Ti 5 O 12 thin films was not yet explained in literature. Kia et al found that the crystalline phase of closely related TiO 2 ALD thin films is influenced by SiO 2 or TiN substrates upon annealing by favoring different nucleation mechanisms.…”

“…Kia et al found that the crystalline phase of closely related TiO 2 ALD thin films is influenced by SiO 2 or TiN substrates upon annealing by favoring different nucleation mechanisms. [38] The significant influence of the interface energy on crystallization temperature is typical for ALD thin films, but not fully understood. [41] The 50% larger thermal expansion coefficient of Li 4 Ti 5 O 12 with 15.6 × 10 −6 K −1 compared to TiN with 10.3 × 10 −6 K −1 could also hamper crystallization.…”

Atomic Layer Deposition of Ni-Co-O Thin-Film Electrodes for Solid-State LIBs and the Influence of Chemical Composition on Overcapacity

“…Numerous studies have addressed the preparation of individual components of thin-film SSLIBs by ALD, such as cathodes [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ], anodes [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ] and solid-state electrolytes [ 50 , 51 , 52 , 53 ]. Using several precursors in the ALD chamber allows the fabrication of all the SSLIB components using ALD equipment [ 12 ].…”

2D Slab Models of Nanotubes Based on Tetragonal TiO2 Structures: Validation over a Diameter Range

“…Among many functional nanomaterials, nanostructured TiO 2 are of great interest due to their unique properties and numerous practical applications [ 14 , 15 , 16 , 17 ]. The main interest in titania-based nanomaterials is basically associated with such high-efficient applications as lithium-ion batteries, solar cells, gas sensors, supercapacitors, etc., [ 18 , 19 , 20 , 21 , 22 , 23 ]. Moreover, active investigations are related to the photocatalytic activity of titania-based materials, including nanopowders and thin films [ 24 , 25 , 26 , 27 , 28 , 29 ].…”