Photoelectric Conversion Layout for Potential-Well-Free Charge Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing photoelectric conversion apparatuses face challenges in enhancing the transfer efficiency of signal charges due to potential wells generated in the charge accumulation regions, which obstruct the movement of signal charges, reducing the transfer characteristic.
Innovation Solution
The apparatus includes a semiconductor layer with specific semiconductor regions and a transport path configuration, where the transport path overlaps with the semiconductor regions in a planar view, and the potential well is minimized by positioning the semiconductor region with a lower impurity concentration to prevent obstruction of charge movement, thereby improving the transfer characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second conductivity type impurity region is formed partially on the transport path to reduce a potential well, then the potential well is reduced, but the movement of signal charges is obstructed, reducing the transfer characteristic
Solution Approach 1:
The first semiconductor region is divided into a first region and a second region with different impurity concentrations. The first region (with higher impurity concentration) is positioned to overlap with the transport path to reduce potential well effects, while the second region (with lower impurity concentration) is positioned away from the transport path to avoid obstructing signal charge movement. This segmentation allows each sub-region to serve its specific function without causing harmful side effects.
Solution Approach 2:
Different regions of the first semiconductor region are assigned different impurity concentrations based on their functional requirements. The first region has a higher impurity concentration optimized for reducing potential wells along the transport path, while the second region has a lower impurity concentration optimized for not obstructing charge movement. This local differentiation of properties resolves the contradiction between reducing potential wells and maintaining charge transport efficiency.
2Reliability
If second conductivity type impurity is implanted into the charge accumulation region to reduce potential well, then potential well is reduced, but transfer performance is reduced due to obstruction of charge movement
Solution Approach 1:
The first semiconductor region is segmented into two distinct regions: a first region with higher impurity concentration positioned to overlap the transport path for potential well reduction, and a second region with lower impurity concentration positioned away from the transport path. This segmentation enables the system to reduce potential wells where needed while preserving charge movement pathways.
Solution Approach 2:
The impurity concentration is locally optimized in different regions of the first semiconductor region. The first region exhibits higher impurity concentration specifically where it overlaps with the transport path to mitigate potential well effects, while the second region maintains lower impurity concentration to avoid obstructing charge transport, thereby achieving local quality differentiation that resolves the technical contradiction.
3Reliability
If second conductivity type impurity is implanted into the periphery of the region where a potential well will be generated, then potential well is reduced, but the transfer efficiency of signal charges is reduced
Solution Approach 1:
The first semiconductor region is divided into a first region and a second region with different impurity concentrations. The first region is positioned to overlap with the transport path to address potential well issues, while the second region is positioned away from the transport path to maintain efficient charge transfer, thus segmenting the functional responsibilities.
Solution Approach 2:
Different impurity concentrations are applied locally within the first semiconductor region based on spatial requirements. The first region has higher impurity concentration where it overlaps the transport path to reduce potential wells, while the second region has lower impurity concentration in areas where charge movement should remain unobstructed, achieving local optimization that resolves the contradiction.
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 enhances the transfer efficiency of signal charges by reducing the potential well effect, preventing charge trapping and improving the overall transfer characteristic of the photoelectric conversion apparatus.
Implementation Method 1
a photoelectric conversion apparatus includes a semiconductor layer, at least one first semiconductor region of a first conductivity type, at least one second semiconductor region of the first conductivity type... a transport path configured to... transport a signal charge generated in the at least one second semiconductor region to the at least one first semiconductor region
Data Source
AI summary
A photoelectric conversion apparatus includes a first semiconductor region, a second semiconductor region, a third semiconductor region between the first and second semiconductor regions, and a fourth semiconductor region at a depth where the first semiconductor region is arranged and has a lower impurity concentration than an impurity concentration of the first semiconductor region. The photoelectric conversion apparatus includes a transport path that overlaps with the first semiconductor region and the second semiconductor region in a planar view. The fourth semiconductor region overlaps with at least a part of the transport path. In the planar view, the first semiconductor region has a first length and a second length longer than the first length. A virtual line that divides the first semiconductor region into two halves in the first direction and extends in the second direction is arranged so as not to overlap with the transport path.