Fabrication of V_1−x Ti _x O₂ microbolometers on Si₃N₄/SiO₂ membranes

Abstract

V1-xTixO2 (VTO) thin films were fabricated on Si3N4/SiO2/Si substrate by fabricating VO2/TiO2 using carbon thermal reduction metal-organic decomposition (MOD). The V0.65Ti0.35O2 thin films exhibited the suppressed resistance-temperature (R-T) characteristic, showed no metal-insulator transition (MIT) during temperature (10~90 ºC), but the temperature coefficient of resistance was high (TCR = -4.24 %/K). The DC sensitivity of the VTO bolometer was 434 W-1. Then, VTO thin films on Si3N4/SiO2 membranes were realized by CF4+O2 (95%+5%) plasma etching at 200 W for 5 min, followed by wet etching of the backside of the substrates, using KOH solution (20% by weight) at 60 ºC for 8 hrs. VTO thin films on Si3N4/SiO2 membranes had a high DC sensitivity of 9876 W-1, which was 20 times higher than the film on Si3N4/SiO2/Si substrate.