Annular Vertical Transfer Gate Pixel for Low-Delay Image Sensing
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Solution Overview
Problem
As image sensors become more integrated, the reduction in pixel size leads to image transmission delays and quality deterioration due to component arrangement and shape, resulting in suboptimal image transmission capabilities.
Innovation Solution
The image sensor design includes a pixel with a photoelectric conversion region and a floating diffusion region in a semiconductor substrate, featuring a vertical transfer gate with an annular shape and an opening in the charge transfer path, which facilitates efficient charge transfer by removing potential barriers and improving transfer characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the degree of integration of an image sensor is increased to reduce pixel size, then the miniaturization of the image sensor is improved, but image transmission delay occurs and image quality deteriorates
Solution Approach 1:
The transfer gate is divided into a first transfer gate extending from the first surface and a second transfer gate extending from the second surface, with each gate handling charge transfer in opposite directions. This segmentation allows simultaneous charge transfer through different paths, reducing transmission delay while maintaining compact pixel size
Solution Approach 2:
The patent utilizes the vertical dimension by extending transfer gates from both the first and second surfaces of the semiconductor substrate into the interior. This three-dimensional arrangement enables charge transfer paths that overcome the limitations of planar two-dimensional layouts, improving charge transfer efficiency without increasing pixel area
2Volume of moving object
If the degree of integration is increased, then device miniaturization is improved, but image quality deteriorates
Solution Approach 1:
The transfer gate is divided into a first transfer gate extending from the first surface and a second transfer gate extending from the second surface, with each gate handling charge transfer in opposite directions. This segmentation allows simultaneous charge transfer through different paths, reducing transmission delay while maintaining compact pixel size
Solution Approach 2:
The patent utilizes the vertical dimension by extending transfer gates from both the first and second surfaces of the semiconductor substrate into the interior. This three-dimensional arrangement enables charge transfer paths that overcome the limitations of planar two-dimensional layouts, improving charge transfer efficiency without increasing pixel area
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 design enhances charge transfer efficiency, prevents transfer delays, and maintains high full-well capacity with low transfer gate-on voltage, resulting in a high-quality image sensor with improved image transmission capabilities.
Implementation Method 1
a photoelectric conversion region in a semiconductor substrate that has a first surface and a second surface that oppose each other
Data Source
AI summary
An image sensor includes at least one pixel, and the pixel includes a photoelectric conversion region in a semiconductor substrate having a first surface and a second surface, a floating diffusion region spaced apart from the photoelectric conversion region in the semiconductor substrate, and a vertical transfer gate that extends into the semiconductor substrate from the first surface of the semiconductor substrate. A transfer channel is between the photoelectric conversion region and the floating diffusion region.