Enhancing the Tunable Sensitivity of a Near-Ultraviolet to Visible to Near-Infrared Photo Irradiance Sensor Using an Indium Tin Oxide-Aluminum Oxide-Zirconia Aluminum Oxide-Silicon

Abstract

This study focuses on enhancing the tunable sensitivity of a photo irradiance sensor (PIS) operating in the near-ultraviolet to visible to near-infrared (NUV-VIS-NIR) spectrum using an indium tin oxide-aluminum oxide-zirconia aluminum oxide-silicon oxide-silicon capacitor (hereafter IAZAOS). Unlike other PIS designs such as reverse-biased metal–insulator–semiconductor (MIS) and tunneling MIS, the IAZAOS PIS measures changes in inversion capacitance under strong forward bias with light irradiation. The IAZAOS PIS offers several key advantages over alternative designs. It exhibits high sensitivity, weak bias dependence, low dark current, tunable sensitivity, low power consumption, CMOS process compatibility, simple low-cost manufacturing, and good gate oxide reliability. Under 1 mW/cm2 irradiation at 1 kHz, the inversion carrier concentration reaches approximately 70% saturation. The resolution achieved is 10 nW/cm2 at 1 kHz, with a sensing range spanning from 10 nW/cm2 to 1 W/cm2 across frequencies from 1 kHz to 100 kHz. These performance characteristics surpass those reported for other PIS technologies. Furthermore, the IAZAOS PIS demonstrates a quantum efficiency of about 60% at 405 nm, which surpasses the quantum efficiency of general silicon-based p(i)n diodes. Post-deposition annealing techniques are employed to enhance the sensor’s performance. Dielectric annealing improves the ZrAlOx interface trap and permittivity properties, while conducting oxide annealing enhances indium tin oxide transmission and resistivity. The combination of these treatments results in a high-speed, high-sensitivity, high-resolution, and reliable NUV-VIS-NIR sensing capability for the IAZAOS capacitor-based PIS.