Compound Semiconductor Imaging Element With Stacked Openings for Pixel Shrink
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Solution Overview
Problem
Current imaging elements using compound semiconductor materials face limitations in design flexibility and miniaturization due to constraints in electrode spacing, which hinders the miniaturization of pixels and enhances the degree of freedom in design.
Innovation Solution
The implementation of a stacked structure with a first insulating layer and a second insulating layer, where the second opening is smaller than the first opening, allows for easier adjustment of the interval between neighboring openings, facilitating pixel miniaturization and enhancing design flexibility by using a compound semiconductor material with a diffusion region of electrically-conductive type impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the interval between electrodes is narrowed to miniaturize pixels, then pixel size is reduced, but manufacturing precision and alignment difficulty worsen
Solution Approach 1:
The insulating layer is divided into a first insulating layer and a second insulating layer stacked in sequence. The first insulating layer contains a first opening with a first width, while the second insulating layer contains a second opening with a second width smaller than the first width. This segmentation allows independent optimization of each opening's dimensions and alignment tolerances, facilitating electrode miniaturization while maintaining manufacturing feasibility.
Solution Approach 2:
Different regions of the insulating structure have different opening widths tailored to specific functional requirements. The first opening provides a larger alignment margin for upper electrode structures, while the second opening provides a smaller, more precise alignment margin for lower electrode structures. This local differentiation of opening qualities enables miniaturization without compromising overall alignment precision.
2Ease of manufacture
If a single insulating layer with uniform opening size is used, then manufacturing is simpler, but design flexibility and miniaturization capability are limited
Solution Approach 1:
The insulating layer is segmented into multiple stacked layers (first and second insulating layers) with differently sized openings. This segmentation transforms a single uniform structure into a multi-level structure where each layer can be independently optimized, significantly enhancing design flexibility for various electrode configurations while maintaining reasonable manufacturing complexity through standardized layering processes.
Solution Approach 2:
The solution transitions from a two-dimensional planar opening structure to a three-dimensional stacked structure with multiple opening levels. By adding the vertical dimension with stacked insulating layers, the patent enables complex electrode arrangements and miniaturization that would be impossible with a single planar layer, while each individual layer remains manufacturable using conventional processes.
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 enables the miniaturization of pixels and enhances the degree of freedom in design, reducing dark current generation and noise while allowing for efficient photoelectric conversion and signal readout.
Implementation Method 1
a photoelectric conversion layer including a compound semiconductor material
Implementation Method 2
including a diffusion region of first electrically-conductive type impurities in a selective region
Data Source
AI summary
An imaging element including: a photoelectric conversion layer including a compound semiconductor material; a contact layer disposed to be stacked on the photoelectric conversion layer and including a diffusion region of first electrically-conductive type impurities in a selective region; a first insulating layer provided to be opposed to the photoelectric conversion layer with the contact layer interposed therebetween and having a first opening at a position facing the diffusion region; and a second insulating layer provided to be opposed to the contact layer with the first insulating layer interposed therebetween and having a second opening that communicates with the first opening and is smaller than the first opening.