Integrated 4H-SiC Photosensors With Active Pixel Sensor-Type Circuits for MGy-Class Radiation Hardened CMOS UV Image Sensor

For radiation-hardened CMOS image sensor (CIS), 4H-SiC photosensors with active pixel sensor (APS)-type circuits were developed and demonstrated. The dark current of 4H-SiC photodiodes was <2 nA/cm2. The spectral sensitivity characteristics were also evaluated in the wavelength from 200 nm to 400 nm. The maximal quantum efficiency was 63% at 270 nm. The photosensors with APS type circuits showed high responses to UV light, demonstrating their operation. High gamma-ray dose experiments were also carried out. The dark current after 2 MGy (SiO2) irradiation was 25 nA/cm2. The photosensors with APS-type were successfully working after 2 MGy exposure.