32×32 very long wave infrared HgCdTe FPAs

Very long wave infrared (VLWIR) band is widely used for the remote atmosphere sounding applications, particularly for humidity, CO2 levels, cloud structure and temperature distribution. A 3232 VLWIR HgCdTe focal plane array (FPA) was designed. The photosensitive component was fabricated by B+ ion implanting As-doped p-type material of liquid phase epitaxial growth on ZnCdTe substrate. The readout integrated circuit (ROIC) used a buffered direct injection (BDI) structure with an improved background suppression. The VLWIR focal plane array (FPA) was achieved by combining the HgCdTe detector with ROIC in terms of indium bump bonds, the cutoff wavelength of which was over 14m. The pixel occupied an area of 60m60m. It could be operated at the temperatures of 50 K. The test results show that the peak detectivity and blackbody responsivity of PFAs are 2.571010 cmHz1/2/W and 1.35 107 V/W, respectively. The nonuniformity of responsivity is about 45%, and dead pixels ratio is less than 12%.