Solid-State Image Sensor Pixel Layout With Shared Diffusion Contacts
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Solution Overview
Problem
In solid-state imaging devices, sharing impurity diffusion regions among multiple pixel regions is challenging due to the complexity of wiring configurations, which hinders miniaturization and increases the risk of signal electric charge inflow between adjacent pixels.
Innovation Solution
A contact electrode is embedded in the semiconductor substrate and positioned over and in contact with impurity diffusion regions of adjacent pixel regions, allowing for electrical coupling and sharing of impurity diffusion regions, thereby simplifying the wiring configuration and reducing contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If impurity diffusion regions are shared among multiple pixel regions, then device miniaturization is enabled and configuration is simplified, but wiring complexity increases and signal electric charge inflow between adjacent pixels may occur
Solution Approach 1:
The patent merges multiple impurity diffusion regions (first, second, third, and fourth impurity diffusion regions) into a shared electric charge accumulation structure. This allows adjacent pixel regions to share common impurity diffusion regions, reducing the overall device volume and simplifying the configuration by eliminating redundant structures while maintaining functional separation through careful spatial arrangement.
Solution Approach 2:
The patent introduces a contact electrode as an intermediary element that electrically couples the shared impurity diffusion regions to the photoelectric converters. This mediator enables the sharing of impurity diffusion regions among multiple pixels while providing controlled electrical connection, thereby reducing wiring complexity and preventing direct signal electric charge inflow between adjacent pixels that would otherwise occur through shared diffusion regions.
2Device complexity
If impurity diffusion regions are shared among multiple pixel regions, then device configuration is simplified, but the risk of signal electric charge inflow between adjacent pixels increases
Solution Approach 1:
The contact electrode serves as a controlled intermediary that manages electrical coupling between shared impurity diffusion regions and photoelectric converters. By providing dedicated contact points, it enables configuration simplification through sharing while maintaining signal electric charge isolation between adjacent pixels, preventing unwanted inflow through the shared diffusion regions.
Solution Approach 2:
The patent applies different impurity concentrations and types in different regions (n-type impurity in photoelectric converters, p-type impurity in surrounding regions) to create local electrical property variations. This local quality differentiation maintains proper electrical isolation and prevents signal electric charge inflow between adjacent pixels while allowing sharing of impurity diffusion regions in the overall configuration.
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 solution enables the sharing of impurity diffusion regions among multiple pixel regions, facilitating miniaturization and simplifying the device configuration while reducing signal electric charge inflow, thus enhancing the imaging device's performance and efficiency.
Implementation Method 1
the contact electrode is provided; therefore, the impurity diffusion regions provided for respective pixel regions adjacent to each other are electrically coupled to each other via the contact electrode
Implementation Method 2
a semiconductor substrate having a first surface and a second surface opposed to each other, and including a photoelectric converter provided for each of pixel regions
Data Source
AI summary
A solid-state imaging device including: a semiconductor substrate having a first surface and a second surface opposed to each other, and including a photoelectric converter provided for each of pixel regions; an impurity diffusion region provided, for each of the pixel regions, in proximity to the first surface of the semiconductor substrate; and a contact electrode embedded in the semiconductor substrate from the first surface, and provided over and in contact with the impurity diffusion regions each provided for each of the pixel regions adjacent to each other.