Visible-blind ultraviolet imagers consisting of $8×8$ AlGaN $p-i-n$ photodiode arrays

We report successful development of both discrete ultraviolet (UV) photodiodes and UV imagers consisting of $8×8$ backside-illuminated AlGaN $p-i-n$ photodiode arrays. The discreteAlGaN $p-i-n$ photodiodes showed a responsivity of $0.1A∕W$⁠, a cutoff wavelength of $350nm$⁠, an external quantum efficiency of 35%, and a response time of $4.1ns$⁠. Then, $8×8$ AlGaN $p-i-n$ photodiode arrays were fabricated, followed by hybridizations with readout integrated circuits manufactured using a $0.5μm$ 2poly-3metal N-well complementary metal-oxide semiconductor process by gold stud bumping. The $8×8$ focal plane array UV imagers operated successfully by sensing radiation in the $300–350nm$ spectral bands.