Enhanced infrared detection characteristics of VOx films prepared using alternating V2O5 and V layers

Abstract

Multilayer VOx films are reported to improve the infrared (IR) detecting characteristics for application as an IR active layer in a microbolometer. Multilayer VOx films formed from the V2O5/V/V2O5 thin film structure showed some advantages in electrical property control and more effective formation of typically unstable vanadium oxide phases. These phases are difficult to achieve by single-layer VOx film fabrication with conventional reactive sputtering. Multilayer VOx films were fabricated by low temperature oxygen annealing at 300 °C after the alternating deposition of stable V and V2O5 layer using rf sputtering. The electrical measurement and microstructural analysis of annealed films were performed to evaluate the advantage of multilayer VOx film fabrication. Owing to the well-controlled mixed phase formation, including V2O3, VO2, and V2O5 in the annealed V2O5/V/V2O5 multilayer film, the temperature coefficient of resistance value and resistivity of the new multilayer VOx film could be increased up to −2.49%/K and reduced less than 0.1 Ω cm, respectively. A single microbolometer pixel of 50×50 μm2, applying this multilayer VOx film, showed total microbolometer resistance of below 20 kΩ to achieve low noise characteristics.