The characteristics of a multifunctional two-colour-avalanche gain Focal Plane Array, FPA, in which one of the bands can be used in avalanche mode to produce current gain with low excess noise and low dark current, are reported.
The multifunctional FPA is based on a bi-colour pseudo-planar MCT detector structure, developed at the CEA-LETI, which superposes two planar type diodes with different composition of Cd. The electro-optic characteristics of the multifunctional LW-MW-avalanche gain detectors are reported for 256x256 30μm pitch arrays hybridised on a bi-colour read-out circuit, and for direct measurements on 30μm pitch test arrays. An avalanche gain of M=5300 at an inverse bias of Vpol=-12.5V and a noise factor close to F=1, is reported for MW wavelength diode, characterised by a cut-off wavelength of λC=5.03μm. A new measure of the sensitivity limit of the APD, the equivalent shot noise limited dark current, ieq_in, was defined and estimated from dark current noise measurements ieq_in=3.0 10-10A at gain M<300 and ieq_in=1.0 10-10A at M=5300. The results will be discussed in view of the wide scope of applications which are enabled by the multifunctional FPAs.