Jin-Hyung Kim, Chang-Rok Moon, Kijoong Yoon, Minsung Heo, Jaehak Lee, I.S. Park, Minhwan Jeon, Jung-Chak Ahn, Bum-Suk Kim, Inho Ro, Hyun-Chul Kim, Taek-Soo Jeon, Jong-uk Kim, Yun-Ki Lee, Kwang-Min Lee, Dongyeon Daniel Kang, Yoon Kisang, Hye Yeon Park, Jungho Park, In-sung Joe, Changkyu Lee, Eunyoung Jo, Dami Park, Chanho Park, JaeSung Hur, Hyoungsub Kim, Chong Kwang Chang, Minkwan Kim, Byun Kyung Rae, Seokjin Kwon, and Tae-Hoon Kim
Sub-micron pixels have been widely adopted in recent CMOS image sensors to implement high resolution cameras in small form factors, i.e. slim mobile-phones. Even with shrinking pixels, customers demand higher image quality, and the pixel performance must remain comparable to that of the previous generations. Conventionally, to suppress the optical crosstalk between pixels, a metal grid has been used as an isolation structure between adjacent color filters. However, as the pixel size continues to shrink to the sub-micron regime, an optical loss increases because the focal spot size of the pixel’s microlens does not downscale accordingly with the decreasing pixel size due to the diffraction limit: the light absorption inevitably occurs in the metal grid. For the first time, we have demonstrated a new lossless, dielectric-only grid scheme. The result shows 29 % increase in sensitivity and +1.2-dB enhancement in Y-SNR when compared to the previous hybrid metal-and-dielectric grid.