RF sputtered thin films of Si1-xGex and Si1-xGexOy were investigated by measuring their composition, electrical, and optical properties. As Si concentration was increased to the Ge to form Si1-xGex films, the resistivity was increased while the activation energy and TCR both were decreased. For Si1-xGexOy films, the addition of O2 to the Si1-xGex, increased the resistivity, activation energy and TCR. The TCR was measured to vary from -2.27%/K to -8.69%/K, while the resistivity varied from 4.22×102 Ω-cm to 3.47×109 Ω-cm. A good atomic composition of Si1-xGexOy to be used in microbolometers as the sensitive layer was found to have a TCR of -5.10%/K with a moderate resistivity of ~104 Ω-cm. Microbolometers using doped Si0.15Ge0.85 and Si0.15Ge0.85Oy thermometers have been fabricated using a polyimide sacrificial layer. The 1/f-noise is observed to be relatively high in the Si1-xGex thin films and microbolometers.