Single Exposure Type Wide Dynamic Range CMOS Image Sensor with Enhanced NIR Sensitivity

2018 Mar

Authors Shunsuke Tanaka, Toshinori Otaka, Kazuya Mori, Norio Yoshimura, Shinichiro Matsuo, Hirofumi Abe, Naoto Yasuda, Kenichiro Ishikawa, Shunsuke Okura, Shinji Ohsawa, Takahiro Akutsu, Ken Wen-Chien Fu, Ho-Ching Chien, Kenny Liu, Alex YL Tsai, Stephen Chen, Leo Teng and Isao Takayanagi

ITE Transactions on Media Technology and Applications

In new markets such as in-vehicle cameras, surveillance camera and sensing applications that are rising rapidly in recent years, there is a growing need for better NIR sensing capability for clearer night vision imaging, in addition to wider dynamic range imaging without motion artifacts and higher signal-to-noise (S/N) ratio, especially in low-light situation. We have improved the previously reported single exposure type wide dynamic range CMOS image sensor (CIS), by optimizing the optical structure such as micro lens shape, forming the absorption structure on the Si surface and adding the back side deep trench isolation (BDTI). We achieved high angular response of 91.4%, high Gr/Gb ratio of 98.0% at ±20°, 610nm, and high NIR sensitivity of QE 35.1% at 850nm, 20.5% at 940nm without degrading wide dynamic range performance of 91.3dB and keeping low noise floor of 1.1e-rms.