Uncooled Infrared Microbolometers and Silicon Germanium Oxide (SixGe1-xOy) Infrared Sensitive Material for Long Wavelength Detection

This report presents a detailed characterization of infrared sensitive silicon germanium oxide SixGeyO1-x-y thin films. The results demonstrated that a high TCR and a low corresponding resistivity can be achieved using various compositions, for example, Si0.054Ge0. 877O0.069 film has achieved a TCR and a resistivity of 3.516K, and 629 ohm-cm, respectively. The lowest measured resistivity and the corresponding TCR were 90.73 ohm-cm and 1.653 K respectively, using Si0.206Ge0.650O0.144 for film deposited at room temperature, whereas the highest achieved TCR and the corresponding resistivity at room temperature were -5.017 K, and 39.1 103 ohm-cm, respectively, using Si0.167Ge0.762O0.071 for films deposited at room temperature. The X-ray diffraction study demonstrated that the films are amorphous. The peak broadening and peak shift was used to explain the dependence of TCR and resistivity on varying silicon at fixed oxygen concentration, and varying oxygen at fixed Si concentration. Raman spectroscopy results are used relate the TCR and resistivity of Si-Ge-O films with the Ge-Si, and Ge-Ge chemical bonding. The spectra showed dependence on varying silicon at fixed oxygen or at fixed Si. Uncooled microbolometers were fabricated with various Si-Ge-O compositions. Voltage noise PSD was measured and optimized, using annealing in vacuum at 200 oC, 250 oC, and 300 oC.