Group III-V Photodiode Pixel Isolation for Charge Recombination
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Solution Overview
Problem
In image sensors using Group III-V semiconductors, signal charges generated in the photoelectric conversion layer can move unevenly across pixels, leading to issues like color mixture and reduced resolution due to the lack of effective charge recombination between adjacent pixels.
Innovation Solution
A light-receiving device is designed with a photoelectric conversion layer including a Group III-V semiconductor, featuring first electrically-conductive type regions for each pixel and a second electrically-conductive type region that penetrates through the layer, positioned between adjacent first regions to recombine signal charges and prevent their movement across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common photoelectric conversion layer is provided continuously over multiple pixels, then the device complexity is reduced and manufacturing is simplified, but signal charges can move unevenly across pixels causing color mixture and reduced resolution
Solution Approach 1:
The patent divides the continuous photoelectric conversion layer into pixel units by introducing second electrically-conductive type regions (isolation regions) between adjacent first electrically-conductive type regions. This segmentation prevents signal charges from moving between pixels while maintaining a relatively simple continuous layer structure for photoelectric conversion, thus resolving the contradiction between device simplicity and charge extraction precision.
2Device complexity
If no isolation structure is provided between pixels, then the device complexity is minimized, but signal charges generated in one pixel can move to adjacent pixels causing color mixture
Solution Approach 1:
The patent introduces second electrically-conductive type regions as intermediary elements between adjacent pixel regions. These isolation regions act as mediators that prevent direct interaction and charge movement between adjacent first electrically-conductive type regions, thereby preventing color mixture while maintaining pixel resolution without requiring complex isolation structures.
3Ease of manufacture
If the photoelectric conversion layer is made continuous to improve manufacturing ease, then signal charge recombination between pixels cannot occur, leading to color mixture
Solution Approach 1:
The patent segments the continuous photoelectric conversion layer by introducing second electrically-conductive type regions between pixels. This allows the layer to be formed continuously for manufacturing ease while the segmentation prevents harmful charge movement between pixels, thus resolving the contradiction between ease of manufacture and prevention of color mixture.
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 prevents signal charge movement between pixels, enhancing image resolution and reducing color mixture by ensuring that charges are recombined within the second electrically-conductive type region, thereby improving the performance of the imaging device.
Implementation Method 1
a photoelectric conversion layer including a Group III-V semiconductor; a plurality of first electrically-conductive type regions in which signal charges generated in the photoelectric conversion layer move
Data Source
Figure 1
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Figure 4A~4C
AI summary
Provided is a light-receiving device including: a photoelectric conversion layer including a Group III-V semiconductor; a plurality of first electrically-conductive type regions in which signal charges generated in the photoelectric conversion layer move; and a second electrically-conductive type region penetrating through the photoelectric conversion layer and provided between adjacent ones of the first electrically-conductive type regions.