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The quantum efficiency and reflectivity of thick, back-illuminated CCD’s being fabricated at the Lawrence Berkeley National Laboratory for astronomical applications are modeled and compared with experiments. The treatment differs from standard thin-film optics in that (a) absorption is permitted in any film, (b) the 200–500 lm thick silicon substrate is considered as a thin film in order to observe the fringing behavior at long wavelengths, and (c) by using approximate boundary conditions, absorption in the surface films is separated from absorption in the substrate. For quantum efficiency measurements, the CCD’s are normally operated as CCD’s, usually at T = -140 °C, and at higher temperatures, as photodiodes. They are mounted on mechanical substrates. Reflectivity is measured on air-backed wafer samples at room temperature. The agreement between model expectation and quantum efficiency measurement is in general satisfactory. [ABSTRACT FROM AUTHOR]

Silicon detectors with very thin entrance contacts have been fabricated for use in the IMPACT SupraThermal Electron (STE) instrument on the STEREO mission and for the Solid State Telescopes on the THEMIS mission. The silicon diode detecters were fabricated using a 200 Å thick phosphorous doped polysili con layer that formed the thin entrance window. A 200 Å thick aluminum layer was deposited on top of the polysilicon in order to reduce their response to stray light. Energy loss in the entrance contact was about 350 eV for electrons and about 2.3 keV for protons. The highest detector yield was obtained using a process in which the thick polysilicon gettering layer was removed by chemical etching rather than chemical mechanical polishing. [ABSTRACT FROM AUTHOR]