Image Sensor Pixel Isolation for Cross-Talk in Small Pixels
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Solution Overview
Problem
The reduction in pixel size of image sensors leads to challenges such as electrical signal cross-talk among pixels, which affects performance, and existing manufacturing techniques struggle to minimize this issue without compromising image quality.
Innovation Solution
The design includes electrically non-conductive isolation structures on a substrate with electrodes in direct contact, an active layer between these structures, and an encapsulation layer without a transparent electrode, along with a buffer layer and condensing structures to prevent electron/hole cross-talk and allow for smaller pixel sizes without performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to increase the number of pixels per unit area, then higher-resolution images can be provided, but electrical signal cross-talk among pixels occurs which adversely affects image sensor performance
Solution Approach 1:
The patent divides the sensor surface into discrete pixel regions separated by isolation structures. Each pixel is electrically isolated from its neighbors through these structures, preventing signal cross-talk while maintaining high pixel density for high-resolution imaging.
Solution Approach 2:
Isolation structures serve as intermediary elements between adjacent pixels. These structures physically and electrically separate pixels, acting as mediators that prevent harmful electrical signal cross-talk while allowing the pixels to function independently at high density.
2Productivity
If pixel size is reduced, then more pixels can be packed per unit area, but manufacturing complexity increases due to the need for new techniques to prevent cross-talk
Solution Approach 1:
The sensor is segmented into modular pixel units with integrated isolation structures. This segmentation approach simplifies manufacturing by allowing standardized fabrication processes to be applied across the entire sensor array, reducing the complexity associated with high-density pixel fabrication.
Solution Approach 2:
The isolation structures are merged with the pixel fabrication process itself, rather than being added as separate post-processing steps. This integration of isolation features into the primary manufacturing flow reduces the number of discrete manufacturing steps and lowers overall manufacturing complexity.
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 configuration effectively reduces electrical cross-talk, enabling the production of high-resolution image sensors with smaller pixel sizes while minimizing manufacturing complexity and interface reflection, thus enhancing image sensor performance and efficiency.
Implementation Method 1
The isolation structures are electrically non-conductive and define pixel regions
Implementation Method 2
signal electric charges may be generated according to the amount of light received in the light-sensing portion
Implementation Method 3
the buffer layer is an electron transport layer or a hole transport layer
Data Source
AI summary
An image sensor is provided. The image sensor includes a substrate and isolation structures disposed on the substrate. The isolation structures are electrically non-conductive and define pixel regions. The image sensor also includes electrodes disposed on the substrate and in direct contact with the isolation structures. The image sensor further includes an active layer disposed between the isolation structures. Moreover, the image sensor includes an encapsulation layer disposed over the active layer. The image sensor also includes a color filter layer disposed over the encapsulation layer.