Patent ID: 8338200

Claim:
A method of fabricating a frontside-illuminated inverted quantum well infrared photodetector focal plane array, the method comprising: providing a quantum well wafer comprising a bulk substrate layer and a quantum material layer comprising a plurality of alternating quantum well layers and barrier layers, wherein the alternating quantum well layers and barrier layers have been epitaxially grown on the bulk substrate layer, the quantum material layer is on a frontside of the quantum well wafer, and the bulk substrate layer is on a backside of the quantum well wafer; applying a plurality of frontside common electrical contacts to the frontside of the quantum well wafer; bonding a transparent substrate to the frontside of the quantum well wafer and the plurality of frontside common electrical contacts, wherein the transparent substrate is transparent to radiation in a predetermined wavelength range; thinning the bulk substrate layer of the quantum well wafer; etching the quantum material layer to form a plurality of quantum well facets that define a plurality of pyramidal quantum well stacks; applying a backside electrical contact to each pyramidal quantum well stack to form a plurality of pixels, wherein the pixels are at least partially reticulated; singulating the quantum well wafer and the transparent substrate into at least one quantum well infrared photodetector array; and bump bonding the backside electrical contacts of the at least one quantum well infrared photodetector array to a read-out integrated circuit assembly, wherein the read-out integrated circuit assembly comprises a read-out integrated circuit assembly bulk substrate that has a coefficient of thermal expansion that is substantially equal to the coefficient of thermal expansion of the transparent substrate.