Effect of Annealing on Electrical and Optical Properties of Tin-Doped Vanadium Oxide Films for Microbolometer Applications

We investigate the effects of post-annealing in oxygen (O2) and nitrogen (N2) on tin-doped vanadium oxide (VxSnyOz) films for microbolometer applications. The films were deposited using magnetron sputtering in an Ar:O2 environment. We demonstrate that low Sn doping combined with N2 post-annealing provides an effective approach to optimize the temperature coefficient of resistance (TCR), resistivity, and 1/f-noise. Compared to undoped VOx, VxSnyOz films exhibit an enhanced TCR, moderate resistivity, and reduced 1/f-noise. The 135 nm thick V0.46Sn0.03O0.51 film after post-annealing in N2 shows a TCR of −4.08%/K and a resistivity of 7.3 × 10−2 Ω⋅cm at 300 K, an absorptance of 63–68% in the 900–2500 nm wavelength range, and low noise voltage power spectral density (1.77 × 10−16 V2/Hz at 100 Hz under 0.3μA bias current). These results indicate that Sn-doped VOx films are promising sensing materials for microbolometer applications.