Uncooled Infrared (IR) focal plane arrays are an enabling technology for both military and commercial high sensitivity night vision cameras. The IR imaging is accomplished using MEMS microbolometers fabricated on read-out integrated circuits (ROIC’s) and depends critically on the material used to absorb the incoming IR radiation. A typical detector works by monitoring changes in the electrical resistance of the detector material as it absorbs the radiation. Thus, suitable detector materials must exhibit a large temperature coefficient of resistance (TCR) and low noise characteristics to efficiently detect IR photons while also maintaining compatibility with standard IC processing. The most commonly used material in uncooled infrared imaging detectors is vanadium oxide deposited by reactive ion beam sputtering. Here we present a comparison of vanadium oxide thin films grown via reactive ion beam sputtering to films grown using reactive pulsed DC magnetron sputtering. Films deposited using both methods were optically and structurally characterized using Raman spectroscopy, transmission electron microscopy, atomic force microscopy, grazing incidence X-ray diffraction and Rutherford backscattering spectroscopy. Electrical properties of the films were also measured and were found to be very sensitive to the deposition conditions used. The ion beam sputtered films were determined to contain twinned FCC VOx nanocrystals with sub-nanometer scale twin spacing, in the form of large 10-20 nm wide columnar/conical grains. In contrast, the magnetron sputtered films consisted of equiax grains of FCC VOx (5-10 nm) encapsulated in an amorphous matrix. Subtle differences in composition and structure could also be determined from the Raman spectra of the films. These differences in microstructure and composition were then correlated to the measured resistivities and TCRs of the films.