5.5 A 2.1e<sup>−</sup> Temporal Noise and −105dB Parasitic Light Sensitivity Backside-Illuminated 2.3µm-Pixel Voltage-Domain Global Shutter CMOS Image Sensor Using High-Capacity DRAM Capacitor Technology
Jaekyu Lee, Seung Sik Kim, In-Gyu Baek, Heesung Shim, Taehoon Kim, Taehyoung Kim, Jungchan Kyoung, Dongmo Im, Jin-Yong Choi, Keunyeong Cho, Daehoon Kim, Haemin Lim, Min-Woong Seo, Ju‐Young Kim, Doowon Kwon, Jiyoun Song, Ji-Yoon Kim, Min‐Ho Jang, Joosung Moon, Hyunchul Kim, Chong Kwang Chang, JinGyun Kim, Kyoungmin Koh, Hanjin Lim, JungChak Ahn, Hyeongsun Hong, Lee Kyupil, Ho-Kyu Kang
Abstract
As the automotive and AI industries are expanding rapidly, global-shutter (GS) image sensors are playing a more significant role in the perception system. More specifically, GS image sensors are required in various fields involving IR, including the face-ID in mobile devices, the driver monitoring system in automotive applications, and factory automation. GS image sensors are necessary for these applications because they can capture freeze-frame images without motion distortion due to their advantage in the pixel operation method. The simultaneous pixel exposure and in-pixel storing capability allow GS image sensors to achieve high-quality imaging, while the sequential pixel exposure and readout of rolling-shutter (RS) image sensors results in image distortion known as the jello effect. For mobile and automotive applications, a small form factor while maintaining a low parasitic light sensitivity (PLS) and low noise is crucial. In conventional backside illuminated (BSI) charge-domain GS image sensors, a light-shielding structure over the storage area must be formed in order to suppress the influence of parasitic light during the readout operation. Therefore, the introduction of such a light-shielding structure reduces the effective photodiode area, which results in a loss of full-well capacity (FWC), light sensitivity of the sensor, and pixel scalability.