Noise reduction strategy for hybrid IR focal-plane arrays

The low background performance of most infrared systems has been limited by the read noise of the focal plane array (FPA). In many cases the cause has been attributed to the use of MOSFETS or to the detector itself. In this paper we describe a multiple correlated sampling technique and demonstrate noise improvements by a factor of 9 over conventional readout techniques in use today. The FPA under discussion is a `Source Follower per Detector' or SFD type readout structure; specifically, the Santa Barbara Research Center 58 X 62 InSb FPA and the Hughes Technology Center (HTC) 256 X 256 PtSi FPA. The quoted read noise for the SBRC FPA (typically 400 electrons rms) has been reduced to 45 electrons rms using this technique.