First Demonstration of High-Sensitivity (NEP<1fW•Hz-1/2) Back-Illuminated Active-Matrix Deep UV Image Sensor by Monolithic Integration of Ga2O3 Photodetectors and Oxide Thin-Film-Transistors

We, for the first time, demonstrated a back-illuminated active-matrix deep UV (DUV) image sensor by monolithically integrating an ultra-wide bandgap (UWBG) Ga 2 O 3 photodetector (PD) array and IGZO thin-film-transistors (TFT) based on a low temperature back-end-of-line (BEOL) process. Benefited from the low off-state current of 10 ^-13 A, high on/off ratio of 5×10 ⁸ , and high stability of IGZO TFTs, the integrated PD/TFT sensor cell presents super-high sensitivity with NEP down to 1fW•Hz ^-1/2 with a high responsivity and specific detectivity of 302A/W and 1.7×10 ¹⁵ Jones, respectively. The 32×32 DUV image sensor shows excellent uniformity and demonstrates a superior image recognition ability with light intensity down to 2 μW/cm ² . This scalable, high-resolution DUV image sensor shows great promise for advanced imaging and machine vision applications.