Development of LPE-grown HgCdTe 64 x 64 FPA with a cutoff wavelength of 10.6 μm

Autor: Hiroyuki Ishizaki, Yuichiro Ito, Kenji Awamoto, Toshio Kanno, Nobuyuki Kajihara, Minoru Saga, Gen Sudo
Rok vydání: 1993
Předmět:
Zdroj: SPIE Proceedings.
ISSN: 0277-786X
Popis: We have developed a hybrid HgCdTe focal plane array (FPA) for wavelengths from 8 to 11 micrometers . We describe how we fabricated our back illuminated 64 X 64-element photodiode array on a liquid phase epitaxial (LPE) HgCdTe wafer, and a Si CCD multiplexer with line address readout. We optimized carrier concentration in the p-type HgCdTe layer to maximize charge injection efficiency to the Si CCD readout circuit to more than 99.3%. We achieved excellent uniformity of characteristics of the photodiode array, which is very important for an IRFPA, by using LPE HgCdTe grown with a tipping method, and passivating the photodiode array with an anodic sulfide of HgCdTe. We obtained an average product of zero-bias resistance and area (RoA) of 9.1 (Omega) cm 2 with a cutoff wavelength of 10.6 micrometers at 77 K. We used line address readout to give a large charge storage capacity of 4 X 10 7 electrons. We estimated a noise equivalent temperature difference (NETD) of 0.08 K with F/2.5 optics, including fixed pattern noise. We tried some preliminary experiments to reduce the crosstalk from photogenerated carriers which spread laterally into the epitaxial layer. We improved the modulation transfer function (MTF) at Nyquist spatial frequency from the conventional 35% to 60% by using a crosswise drain structure around each photosensitive n + on p diode.
Databáze: OpenAIRE