A 120-ke- Full-Well Capacity 160-µV/e- Conversion Gain 2.8-µm Backside-Illuminated Pixel with a Lateral Overflow Integration Capacitor

Isao Takayanagi; Ken Miyauchi; Shunsuke Okura; Kazuya Mori; Junichi Nakamura; Shigetoshi Sugawa

doi:10.3390/s19245572

A 120-ke^- Full-Well Capacity 160-µV/e^- Conversion Gain 2.8-µm Backside-Illuminated Pixel with a Lateral Overflow Integration Capacitor

Sensors (Basel). 2019 Dec 17;19(24):5572. doi: 10.3390/s19245572.

Authors

Isao Takayanagi¹, Ken Miyauchi¹, Shunsuke Okura², Kazuya Mori¹, Junichi Nakamura¹, Shigetoshi Sugawa³

Affiliations

¹ Brillnics Japan Inc., 6-21-12 Minami-Oi, Shinagawa-ku, Tokyo 140-0013, Japan.
² Department of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga 525-8577, Japan.
³ Graduate School of Engineering, Tohoku University, 6-6-11-811, Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.

Abstract

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.

Keywords: CMOS image sensor; backside illumination; high full-well capacity; high sensitivity; lateral overflow integration capacitor; single exposure; wide dynamic range.