Vanadium Oxide Thin Films Obtained by Thermal Annealing of Layers Deposited by RF Magnetron Sputtering at Room Temperature

Abstract

This chapter describes a new deposition method proposed to achieve Vanadium Oxide VO x /V 2 O 5 thin films with high temperature coefficient of resistance (TCR), intended to be used as functional material in IR microsensors (bolometers). The main aim of the work is to attain a deposition method compatible with the lift-off microstructuring technique in order to avoid the use of a reactive-ion etching (RIE) process step to selectively remove the VO x /V 2 O 5 deposited layer in the course of the definition of the bolometer geometry, preventing the harmful effects linked to the spatial variability and the lack of selectivity of the RIE process. The proposed technique makes use of a two-stage process to produce the well-controlled VO x or V 2 O 5 thin films by applying a suitable thermal annealing to a previously deposited layer, which was obtained before at room temperature by RF magnetron sputtering and patterned by lift-off. A set of measurements has been carried out with thin films attained in order to check the quality and properties of the materials achieved with this method. The results reached with V 2 O 5 pure phase films are consistent with a charge transport model based on the small polarons hopping derived from Mott's model under the Schnakenberg form.

Small Polaron Hopping to Efros–Shklovskii-Like Variable Range Hopping Transition in Graphene-Wrapped V2O5 Nanoparticles: The Roleplay of the Mott Gap

“…σ dc is best fitted to the Arrhenius equation given by eq , showing 1000/ T temperature dependence. σ dc · T = σ 0 normale prefix− E σ / ( k B T ) This is shown in Figure c. From the fit, the activation energy E σ is calculated as 0.264 eV …”

“…From the fit, the activation energy E σ is calculated as 0.264 eV. 43 The dielectric relaxation time scales τ d as a function of temperature follow Arrhenius behavior, and the fit according to eq 9b is shown in Figure 4d. From the fit, the activation energy E d is calculated as 0.244 eV.…”