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

Thin films of Si1−xGex and Si1−xGexOy were deposited by radio frequency (rf) magnetron sputtering at room temperature from a single target of Si1−xGex in the Ar or Ar:O2 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 Si1−xGex films, the temperature coefficient of resistance (TCR) was decreased. For Si1−xGexOy films, the addition of oxygen to the Si1−xGex, 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 Si1−xGexOy. A suitable atomic composition of Si1−xGexOy for uncooled infrared detector applications was found to have a TCR of − 5.10%/K.