Hybrid UV Active Pixel Sensor Implemented Using GaN MSM UV Sensor and Si-Based Circuit

Abstract

A hybrid active pixel sensor (APS) was implemented for ultraviolet (UV) imagers by combining a metal–semiconductor–metal (MSM)-type GaN UV sensor and a standard Si CMOS APS controller. The photodetector region of the APS circuit was replaced by a GaN MSM UV sensor, and it was connected together on the printed circuit board with standard Si CMOS APS circuit chip. The dark and photoresponsive current densities of the fabricated MSM UV sensor were $2.5 \times 10^{\mathrm {\mathbf {-6}}}$ and $1.6 \times 10^{\mathrm {\mathbf {-3}}}$ A/cm $^{\mathrm {\mathbf {2}}}$ , respectively, at 10 V bias. The fabricated hybrid UV APS has clearly distinguishable ON/OFF operation states under dark and 365-nm UV irradiation conditions. The calculated photoresponsivity of the hybrid-type GaN UV APS was as high as 5.1 V/W.