Photoelectric Conversion Electrode Depth Layout for Low-Noise Pixels
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Solution Overview
Problem
Existing photoelectric conversion devices do not effectively suppress noise generated by embedded contact electrodes, which can lead to reduced signal quality and increased dark current, affecting the miniaturization and efficiency of pixel arrays.
Innovation Solution
The photoelectric conversion device incorporates a first and second embedded electrode with different depths on opposing surfaces of a substrate, optimizing the connection geometry to reduce contact resistance and dark current while maintaining miniaturization benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If embedded contact electrodes are used to achieve miniaturization of pixels, then pixel size is reduced, but noise is generated in the embedded contact electrode
Solution Approach 1:
The patent transitions from a single-depth embedded electrode design to a multi-depth configuration where the first embedded electrode extends to a first depth and the second embedded electrode extends to a second depth greater than the first depth. This dimensional change in electrode depth allows for separate optimization of signal charge transfer (first electrode) and noise suppression (second electrode), resolving the contradiction between miniaturization and noise generation.
Solution Approach 2:
The embedded electrode system is segmented into two distinct electrodes with different depths and functions. The first embedded electrode is optimized for charge transfer efficiency, while the second embedded electrode is optimized for noise suppression. This segmentation allows each electrode to be independently designed and positioned to address specific requirements, eliminating the noise issue while maintaining miniaturization benefits.
2Area of moving object
If embedded contact electrodes are used for miniaturization, then pixel area is reduced, but dark current increases
Solution Approach 1:
The patent introduces a depth dimension differentiation where the second embedded electrode extends deeper into the semiconductor substrate than the first embedded electrode. This deeper positioning allows the second electrode to effectively suppress dark current by providing an alternative low-resistance path, while the first electrode maintains efficient charge transfer. This resolves the contradiction between reduced pixel area and increased dark current.
3Reliability
If contact resistance is reduced through embedded electrodes, then signal quality improves, but noise is generated
Solution Approach 1:
The electrode system is divided into two segmented components with distinct roles. The first embedded electrode provides low contact resistance for high-quality signal transfer, while the second embedded electrode specifically targets noise suppression. This functional segmentation allows simultaneous optimization of signal quality and noise reduction, resolving the contradiction between these two parameters.
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 suppresses noise and dark current, enhancing signal quality and allowing for further miniaturization of pixel arrays while maintaining efficient charge transfer.
Implementation Method 1
a conversion unit being arranged in the first substrate... configured to transfer a signal charge generated in the conversion unit
Data Source
AI summary
A conversion device includes a first component including a first substrate, a conversion unit, a diffusion portion, and a transfer gate. The first substrate includes a first surface and a second surface opposed to the first surface. The conversion unit is arranged in the first substrate. The first component further includes a first embedded electrode connected to the conversion unit, and a second embedded electrode connected to the diffusion portion. A depth from the first surface to an end portion of the first embedded electrode on a second surface side and a depth from the first surface to an end portion of the second embedded electrode on the second surface side are different from each other.