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

Multilayer VO_x films are reported to improve the infrared (IR) detecting characteristics for application as an IR active layer in a microbolometer. Multilayer VO_x 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 VO_x film fabrication with conventional reactive sputtering. Multilayer VO_x 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 VO_x 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 VO_x 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 VO_x film, showed total microbolometer resistance of below 20 kΩ to achieve low noise characteristics. © 2003 American Vacuum Society.