Radio Frequency sputtered Si1−xGex and Si1−xGexOy thin films for uncooled infrared detectors

Abstract Thin films of Si 1− x Ge x and Si 1− x Ge x O y were deposited by radio frequency (rf) magnetron sputtering at room temperature from a single target of Si 1− x Ge x in the Ar or Ar:O 2 environment. The silicon and oxygen concentrations were varied in a parametric investigation of the dependence of the electrical and optical characteristics of the thin films on composition. As Si concentration was increased in the Si 1− x Ge x films, the temperature coefficient of resistance (TCR) was decreased. For Si 1− x Ge x O y films, the addition of oxygen to the Si 1− x Ge x , increased the activation energy and TCR. The TCR was measured to vary from − 2.27% to − 8.69%/K. The optical bandgap was increased with the increasing concentration of oxygen in Si 1− x Ge x O y . A suitable atomic composition of Si 1− x Ge x O y for uncooled infrared detector applications was found to have a TCR of − 5.10%/K.

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