Chalcopyrite Image Sensor Pixel Segmentation via N-Type Layer
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Solution Overview
Problem
Existing solid-state image pickup units face challenges in achieving both micro-fabrication of pixels and improved sensitivity, particularly when using a p-type chalcopyrite semiconductor structure, as traditional device separation methods lead to increased dark current and processing difficulties.
Innovation Solution
A solid-state image pickup unit is designed with a p-type compound semiconductor layer of a chalcopyrite structure, where an n-type layer is separated for each pixel without processing the p-type layer, allowing electrical separation of the p-type compound semiconductor layer, thereby improving sensitivity and micro-fabrication without increasing dark current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the p-type compound semiconductor layer is physically separated for each pixel, then pixel micro-fabrication is achieved, but manufacturing complexity and processing defects increase
Solution Approach 1:
The n-type layer is segmented into pixel-separated regions while the p-type compound semiconductor layer remains continuous. This segmentation approach achieves electrical isolation between pixels through the patterned n-type layer, eliminating the need to physically separate the sensitive p-type photoelectric conversion layer, thus reducing manufacturing complexity and processing defects.
Solution Approach 2:
The n-type layer serves as an intermediary structure that provides electrical separation between pixels. By patterning the n-type layer rather than the p-type layer, it acts as a mediator that enables pixel isolation without subjecting the photoelectric conversion layer to complex processing steps, thereby reducing manufacturing complexity.
2Reliability
If traditional device separation methods are used, then pixel isolation is achieved, but dark current increases
Solution Approach 1:
The n-type layer is segmented into pixel-specific regions that provide electrical isolation. This segmentation achieves pixel isolation through the patterned n-type layer while keeping the p-type layer continuous and intact, preventing the generation of dark current that would result from processing-induced defects in traditional separation methods.
Solution Approach 2:
The electrical properties are changed by patterning the n-type layer to create pixel-isolated regions. This parameter change in the n-type layer's spatial distribution provides electrical isolation between pixels without physically dividing the p-type layer, thereby maintaining low dark current levels while achieving reliable signal quality.
3Manufacturing precision
If the p-type compound semiconductor layer is processed for pixel separation, then micro-fabrication is achieved, but sensitivity decreases due to processing defects
Solution Approach 1:
The segmentation is applied to the n-type layer rather than the p-type compound semiconductor layer. This approach achieves pixel micro-fabrication through precise patterning of the n-type layer while leaving the p-type layer continuous and unprocessed, thereby maintaining high sensitivity by avoiding processing defects in the photoelectric conversion material.
Solution Approach 2:
The n-type layer serves as an intermediary that absorbs the micro-fabrication processing steps. By patterning the n-type layer to define pixel boundaries, the sensitive p-type layer is protected from direct processing, maintaining its high sensitivity while still achieving precise pixel size control through the intermediary n-type structure.
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 approach enables the achievement of both micro-fabrication of pixels and enhanced sensitivity by avoiding processing-related defects and dark current issues, making it suitable for high-performance imaging applications.
Implementation Method 1
a compound semiconductor of a p-type chalcopyrite structure is applied, as a photoelectric conversion film high in optical absorption coefficient, to an image sensor to achieve high sensitivity
Data Source
AI summary
A solid-state image pickup unit includes: a p-type compound semiconductor layer of a chalcopyrite structure; an electrode formed on the p-type compound semiconductor layer; and an n-type layer formed separately for each pixel, on a surface opposite to a light incident side of the p-type compound semiconductor layer.