Monolithic planar InGaAs detector arrays for uncooled high-sensitivity SWIR imaging

There are few choices when identifying detector materials for use in the SWIR wavelength band. We have exploited the direct-bandgap InGaAs material system to achieve superior room temperature (293°K) dark current. We have demonstrated sensitivity from 400nm through 2.6um with this material system and thus provide the opportunity to sense not only the visible, but also the J-band (1.25um), H-band (1.65um) and K-band (2.2um) windows. This paper discusses the advantages of our hybridized CMOS-InGaAs material system versus other potential SWIR material systems. The monolithic planar InGaAs detector array enables 100% fill factor and thus, high external quantum efficiency. We have achieved room-temperature pixel dark current of 2.8fA and shot noise of 110 electrons per pixel per second. Low dark current at +300K allows uncooled packaging options, affording the system designer dramatic reductions in size, weight (cameras <28grams), and power (<2.5W). Commercially available InGaAs pin arrays have shown diode lifetime mean time between failures (MTBF) of 10¹¹hours for planar InGaAs detectors¹, far exceeding telecom-grade reliability requirements. The use of a hybrid CMOS-InGaAs system allows best of breed materials to be used and permits efficient, cost-effective, volume integration. Moreover, we will discuss how the InGaAsP material system is compatible with CMOS monolithic integration. Taken together, these advantages, we believe, make InGaAs the obvious choice for all future SWIR systems.