Extended wavelength InGaAs infrared (1.0-2.4 μm) detector arrays on SCIAMACHY for space-based spectrometry of the Earth atmosphere

Space qualified InGaAs solid-state array detectors, covering the near-infrared 1-2.4 mum wavelength range, have been developed for application in space-based spectroscopy of the Earth atmosphere. The SCIAMACHY atmospheric chemistry instrument on the ESA ENVISAT satellite (2002-2005) will be equipped with a series of these novel detectors. Detectors are arranged in linear arrays of 1024 pixels of 25 x 500 mum(2) dimension and meet requirements on modestly low operating temperature (150 K) and low levels of dark current and noise. In this paper the underlying physics of dark current and noise of the detector system is studied on the basis of a theoretical model in combination with measurements. At 2.4 mum wavelength the dark-current performance achieved is 20-100 fA at an operating temperature of 150 K and a bias voltage of -2 mV. This corresponds to a figure of merit for detector resistance Ro times detector pixel area A of R(0)A = 2.5-12.5 M Ohm cm(2). This result has required the development of a customised multiplexer for parallel detector read-out at near-zero bias voltage. Further reduction of the operating temperature will not result in lowering the dark current and noise of the InGaAs detectors which are shown to be limited by tunnelling current. A route to future improvement is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.