CMOS Image Sensor Trench Layout for Dark Current and Pixel Charge

The patent divides the trench structure into multiple segments: a first trench with P-type and N-type diffusion layers for charge storage, and a second trench without these layers for maintaining substrate pinning. This segmentation allows different regions to serve different functions - one for increasing saturated charge capacity and another for preserving Dark characteristics by preventing dark current generation.

The patent applies different structural qualities to different locations: the first trench region has P-type and N-type diffusion layers to create strong electric fields for charge accumulation, while the second trench region lacks these layers to maintain substrate pinning and prevent dark current. This local differentiation resolves the contradiction by optimizing each region for its specific function.

The patent segments the pixel structure into distinct functional zones: charge storage regions with strong electric fields formed in first trenches, and transistor arrangement regions associated with second trenches that lack these electric field-forming layers. This spatial segmentation allows transistors to be positioned in areas where they will not interfere with charge storage while still benefiting from the increased saturated charge capacity.

The patent utilizes vertical dimensionality by forming trenches that extend into the substrate, creating strong electric fields in the vertical direction within specific trench regions. This allows charge storage functionality to be achieved in the depth dimension rather than competing for horizontal planar space, thereby preserving area for transistor arrangement.