Solid-State Imaging Device Charge Accumulation Region Potential Distribution
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Solution Overview
Problem
Solid-state imaging devices face challenges in achieving high sensitivity and saturated charge quantity while maintaining efficient charge transfer, as existing technologies like Japanese Patent Laid-Open No. 2000-236081 do not adequately address these requirements.
Innovation Solution
A solid-state imaging device with a photoelectric conversion unit featuring a charge accumulation region where a potential distribution with multiple steps is formed, with the magnitude of each step increasing further away from the transfer unit, enhancing sensitivity and saturated charge quantity while maintaining transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a uniform potential gradient is formed in the charge accumulation region, then charge transfer efficiency is improved, but sensitivity and saturated charge quantity deteriorate
Solution Approach 1:
The patent applies local quality by creating different potential gradient characteristics in different regions of the charge accumulation region. Specifically, the potential distribution is designed to have a first gradient in a first region and a second gradient in a second region, with the second gradient being smaller than the first. This allows the near region (first region) to have strong electric field for efficient charge transfer, while the far region (second region) has weaker electric field to maintain higher potential and improve sensitivity and saturated charge quantity.
2Speed
If a uniform potential gradient is formed in the charge accumulation region, then charge transfer speed is improved, but saturated charge quantity deteriorates
Solution Approach 1:
The patent applies local quality by creating different potential gradient characteristics in different regions of the charge accumulation region. Specifically, the potential distribution is designed to have a first gradient in a first region and a second gradient in a second region, with the second gradient being smaller than the first. This allows the near region (first region) to have strong electric field for efficient charge transfer, while the far region (second region) has weaker electric field to maintain higher potential and improve sensitivity and saturated charge quantity.
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
The proposed solution improves both sensitivity and saturated charge quantity while maintaining efficient charge transfer, outperforming existing technologies in terms of performance metrics such as the number of saturated electrons and transfer efficiency.
Implementation Method 1
Japanese Patent Laid-Open No. 2000-236081 proposes technology for forming a potential gradient at each point in a charge accumulation region of a photoelectric conversion unit so that a charge generated in the photoelectric conversion unit is rapidly and completely transferred to a transfer electrode by electric field drift.
Data Source
AI summary
A solid-state imaging device includes a photoelectric conversion unit that has a charge accumulation region and is configured to accumulate a charge that is generated in accordance with incident light in the charge accumulation region, and a transfer unit configured to transfer the charge accumulated in the charge accumulation region from the charge accumulation region. A potential distribution having a plurality of steps is formed in the charge accumulation region, and the further away from the transfer unit a step of the plurality of steps is, the greater the magnitude of the step is.