A 120-ke⁻ full-well capacity 160-µV/e⁻ conversion gain 2.8-µm backside-illuminated pixel with a lateral overflow integration capacitor

In this paper, a prototype complementary metal-oxide-semiconductor (CMOS) image sensor with a 2.8-µm backside-illuminated (BSI) pixel with a lateral overflow integration capacitor (LOFIC) architecture is presented. The pixel was capable of a high conversion gain readout with 160 µV/e⁻ for low light signals while a large full-well capacity of 120 ke⁻ was obtained for high light signals. The combination of LOFIC and the BSI technology allowed for high optical performance without degradation caused by extra devices for the LOFIC structure. The sensor realized a 70% peak quantum efficiency with a normal (no anti-reflection coating) cover glass and a 91% angular response at ±20^◦ incident light. This 2.8-µm pixel is potentially capable of higher than 100 dB dynamic range imaging in a pure single exposure operation.