WORKSHOP PAPER
Novel non-metallic pixel isolation technology for high sensitivity in CMOS image sensors with submicron pixels
Hye Yeon Park1, Yunki Lee1, In-Sung Joe2, Boseong Kim1, Taehan Kim1, Jeongmin Bae1, Hyunseok Song1, Kwangmin Lee2, Minsung Heo2, Jinhyung Kim2, Jaehak Lee3, Jungho Park3, Hyunchul Kim2, Chang-Rok Moon2, Bumsuk Kim1, JungChak Ahn1, Duckhyun Chang1
1System LSI Division, Samsung Electronics Co., Ltd, Yongin-city, Gyeonggi-do, Korea
2Samsung Electronics, Semiconductor R&D Center,
3Foundry Division, Samsung Electronics Co., Ltd, Yongin-city, Gyeonggi-do, Korea

Abstract

Demand for high-resolution multiple cameras leads to competition to decrease size of pixels, and image sensor products with submicron-sized pixel coming to the market. Technologies of CMOS Image Sensor (CIS) have been developed to produce high quality images even with small pixel size and being limited area of image sensor. Based on 3D finite-difference time-domain (FDTD) simulations including color filter properties and device spectrometry, we concluded that major light loss was caused by the metallic grid structure (71.4%) and developed non-metallic pixel isolation structure that eliminates optical losses for high performance in the world’s highest resolution image sensors for mobile applications. By this sensitivity maximization technology, image quality in high resolution camera using small pixels and non-metallic pixel isolation increases SNR (+0.7 dB) and sensitivity (+15%) compared with pixel isolation with hybrid grid. This innovative technology will be used in smaller pixel generations in order to provide superior image quality.
Publisher: IISS (Int. Image Sensors Society)
Year: 2021
Workshop: IISW
URL: https://doi.org/10.60928/v2vu-s6s4
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Keywords

CMOS Image Sensors, Pixel Isolation, High Sensitivity,

References

1) Y. Kim et al., "A 1/2.8 -inch 24M pixel CMOS image sensor with 0.9 ㎛ pixels separated by full-depth trench isolation. Proc. ISSCC", ISSCC, 2018. https://doi.org/10.1109/isscc.2018.8310195
2) S. Choi et al., "An all pixel PDAF CMOS image sensor with 0.64 ㎛ x 1.28㎛ photodiode separated by self-aligned in-pixel deep trench isolation for high AF performance. IEEE Symp., VLSI Tech.", VLSI Tech., 2017. https://doi.org/10.23919/vlsit.2017.7998212
3) Y. Lee et al., "World first mass productive 0.8μm pixel size image sensor with new optical isolation technology to minimize optical loss for high sensitivity. International Image Sensor Workshop (IISW)", International Image Sensor Workshop (IISW), 2019. https://doi.org/10.60928/ka1i-9po0
4) I. Joe et al., "Development of Advanced Inter-Color-Filter Grid on Sub-Micron-Pixel CMOS Image Sensor for Mobile Cameras with High Sensitivity and High Resolution, VLSI", VLSI, 2021. https://doi.org/10.23919/vlsicircuits52068.2021.9492339