Impact of excess low-frequency noise (ELFN) in Si:As impurity band conduction (IBC) focal plane arrays for astronomical applications

Abstract

Long wavelength, infrared focal plane arrays (IRFPAs) fabricated with arsenic doped silicon (Si:As), impurity band conduction (IBC) detectors are being utilized in astronomical applications. In these systems, long integration times and/or the co-addition of consecutive frames are typically used to increase the signal-to-noise ratio. Some of the IBC detectors used in these IRFPAs have exhibited Excess Low Frequency Noise (ELFN) which limits their performance under some operational conditions. Data are presented on two Si:As IRFPAs which exhibit ELFN. These data illustrate the parametric dependence of ELFN on detector bias, photon irradiance, and integration time. Additionally, noise spectra from a single detector with ELFN illustrate the frequency dependence of ELFN at several photon irradiances. Finally, the effectiveness of the co- addition of frames on improving the signal-to-noise ratio when using an IRFPA with ELFN is quantified.