Combining single source chemical vapour deposition precursors to explore the phase space of titanium oxynitride thin films

Abstract

In this paper we report on a novel chemical vapour deposition approach to the formation and control of composition of mixed anion materials, as applied to titanium oxynitride thin films. The method used is the aerosol assisted chemical vapour deposition (AACVD) of a mixture of single source precursors. To explore the titanium-oxygen-nitrogen system the single source precursors selected were tetrakis(dimethylamido) titanium and titanium tetraisopropoxide which individually are precursors to thin films of titanium nitride and titanium dioxide respectively. However, by combining these precursors in specific ratios in a series of AACVD reactions at 400 °C, we are able to deposit thin films of titanium oxynitride with three different structure types and a wide range of compositions. Using this precursor system we can observe films of nitrogen doped anatase, with 25% anion doping of nitrogen; a new composition of pseudobrookite titanium oxynitride with a composition of Ti3O3.5N1.5, identified as being a UV photocatalyst; and rock-salt titanium oxynitride in the range TiO0.41N0.59 to TiO0.05N0.95. The films were characterised using GIXRD, WDX and UV-vis spectroscopy, and in the case of the pseudobrookite films, assessed for photocatalytic activity. This work shows that a so-called dual single-source CVD approach is an effective method for the deposition of ternary mixed anion ceramic films through simple control of the ratio of the precursors, while keeping all other experimental parameters constant.

Reliable Resistive Switching and Synaptic Behaviors Based on a TiOx‐Doped N Memristor for Information Storage and Neuromorphic Computing

“…For the TiN/TiO x N y /Pt devices, the uniform CFs (i.e., oxygen vacancy) were easily formed in the vicinity of TiN under positive voltage because this is similar to metal nanoparticles promoting the enhancement of the electric field, thereby resulting in the improvement of RS performance (Figure 5a,b). [ 46–48 ] This is consistent with the observation from the C‐AFM. Following the SCLC conduction mechanism, the electrons were trapped in TiN y , as shown in Figure 5b.…”

“…We believe that the conductive TiN y may be formed in the film, which can act as the capture center. [46][47][48] To further identify the SCLC, a linear relation was observed in the graph of ln(I) and V 1/2 (Figure 3b) at a low voltage (<0.3 V) according to…”

“…We believe that the conductive TiN y may be formed in the film, which can act as the capture center. [ 46–48 ] To further identify the SCLC, a linear relation was observed in the graph of ln( I ) and V 1/2 (Figure 3b) at a low voltage (<0.3 V) according to where A , T , k , Φ, q , d , and ϵ are the Richardson constant, temperature, Boltzmann constant, Schottky barrier, charge quantity, film thickness, and dielectric constant, respectively. [ 43,49 ] As the electric field lowers the Coulomb barrier of the electron, it increases the possibility of being thermally excited from the trap.…”

Observation of visible light activated photocatalytic degradation of stearic acid on thin films of tantalum oxynitride synthesized by aerosol assisted chemical vapour deposition

“…The tantalum oxide thin films were deposited by AACVD using a cold walled reactor; details of the reactor have been published previously. 48 Depositions were carried out from a solution of the tantalum (V) ethoxide in toluene using argon as a carrier gas. All precursor chemicals were handled under an atmosphere of argon (BOC, Pureshield) using standard Schlenk and glovebox techniques.…”

Demonstration of Visible Light-Activated Photocatalytic Self-Cleaning by Thin Films of Perovskite Tantalum and Niobium Oxynitrides

“…A piezoelectric device was used to generate an aerosol mist of the aluminum precursor solution, which was subsequently transported into the AACVD reactor under a flow of argon gas (BOC, Pureshield). 40 The reactor temperature was set at 500 °C and the gas flow to 1 L min −1 . After deposition, the alumina-coated silica was annealed in air at 1100 °C for 10 h with a 3 °C min −1 heating rate.…”