This proposal introduces an innovative concept aimed to develop, for the first time, a 1k pixel far infrared focal-plane array with the following key design features: 1- A top-illuminated, 2D germanium array (32x32 single or 64x64 mosaic) with the possibility of extension to very large formats. The quantum efficiency is enhanced by metalizing the bottom surface for a second pass. 2- A 2-side buttable 32x32 (64x64 mosaic) CTIA readout multiplexer using advanced cryo-CMOS process. The unit-cell design is optimized for far IR detectors, eliminates detector debiasing, and improves pixel uniformity. The readout is operational down to at least 2.0K. 3- A novel, direct hybrid design using indium-bump technology. This integrated design offers superior noise performance and effectively addresses the readout glow, detector heating, and thermal mismatch between the detector and the readout. This is the key discriminator of this project. The projected sensitivity of this array as well as the 1k pixel (4k pixel mosaic) format meets the stated requirements of future NASA instruments. This effort fits well within the scope of the SBIR Subtopic S4.01 and will be a benefit to many large and small NASA projects such as SOFIA and SAFIR.
