Pixel Isolation Layout for Dense Image Sensors With Lower Cross-Talk
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Solution Overview
Problem
Current CMOS image sensors face challenges in minimizing cross-talk between pixels and maintaining gate electrode size as integration density increases, leading to potential deterioration in image sensor performance.
Innovation Solution
The implementation of a deep device isolation pattern with specific portions spaced apart in different directions between pixel regions, along with extended active patterns, helps minimize cross-talk and allows for increased gate electrode size, thereby enhancing integration density without reducing gate electrode performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If integration density is increased, then more pixels can be packed into the sensor, but cross-talk between adjacent pixels increases and gate electrode size must be reduced
Solution Approach 1:
The deep device isolation pattern is divided into first portions extending in a first direction and second portions extending in a second direction crossing the first direction, creating a grid-like segmentation that effectively isolates adjacent pixels in both directions while minimizing cross-talk
Solution Approach 2:
The isolation pattern is configured with different portions (first and second portions) oriented in different directions, providing localized isolation quality tailored to the specific geometric arrangement of pixels, thereby optimizing cross-talk reduction for each pixel region
2Quantity of substance
If integration density is increased, then more pixels can be packed into the sensor, but gate electrode size must be reduced which deteriorates performance
Solution Approach 1:
The active pattern is extended in a direction crossing the extension direction of the deep device isolation pattern, utilizing the third dimension (depth) and orthogonal planar direction to increase gate electrode area without increasing the footprint in the primary pixel arrangement direction, thereby maintaining high integration density while preserving gate electrode performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces cross-talk between adjacent pixels and allows for larger gate electrodes, improving the integration density and performance of the image sensor.
Implementation Method 1
Each of the pixels may include a photodiode (PD) that converts incident light into an electrical signal
Data Source
AI summary
An image sensor includes a substrate having a plurality of pixel regions and a deep device isolation pattern disposed in the substrate between the pixel regions. The pixel regions include first, second, third, and fourth pixel regions, which are adjacent to each other in first and second directions. The deep device isolation pattern includes first portions interposed between the first and second pixel regions and between the third and fourth pixel regions and spaced apart from each other in the second direction, and second portions interposed between the first and third pixel regions and between the second and fourth pixel regions and spaced apart from each other in the first direction. The first pixel region includes a first extended active pattern, which is extended to the second pixel region in the first direction and is disposed between the first portions of the deep device isolation pattern.