Solid-State Image Sensor Pixel Structure for Quantum Efficiency
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Solution Overview
Problem
Conventional stacked-type solid-state imaging devices face inefficiencies in storing charges generated in organic photoelectric conversion films, leading to decreased quantum efficiency.
Innovation Solution
A solid-state imaging device with a matrix arrangement of pixels, each comprising a first semiconductor layer, a photoelectric conversion section, an accumulation electrode, wiring, a floating diffusion region, and a gate electrode, optimized to enhance charge transfer and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charges are generated in the organic photoelectric conversion film, then photoelectric conversion occurs, but the charges cannot be efficiently stored in the semiconductor layer below
Solution Approach 1:
The semiconductor layer is divided into multiple regions with different potential characteristics: a first region directly beneath the organic photoelectric conversion film and a second region adjacent to it. This segmentation allows differentiated charge storage functions across the semiconductor layer, improving overall charge storage efficiency while maintaining quantum efficiency.
Solution Approach 2:
Different regions of the semiconductor layer are assigned different potential characteristics tailored to their specific functions. The first region has potential characteristics optimized for receiving charges from the organic photoelectric conversion film, while the second region has characteristics optimized for charge accumulation and transfer. This local optimization resolves the contradiction between charge storage efficiency and quantum efficiency.
2Measurement precision
If a stacked-type structure is used with organic photoelectric conversion film, then false colors are reduced, but charge transfer efficiency to the semiconductor layer decreases
Solution Approach 1:
The semiconductor layer is segmented into regions with different potential characteristics to optimize charge transfer from the organic photoelectric conversion film. This segmentation maintains the stacked-type structure's color accuracy benefits while resolving the charge transfer efficiency problem through specialized regional functions.
Solution Approach 2:
The first region of the semiconductor layer acts as an intermediary between the organic photoelectric conversion film and the second region. It receives charges from the organic film and facilitates their transfer to the second region, thereby improving overall charge transfer efficiency while maintaining the color accuracy advantages of the stacked structure.
3Quantity of substance
If charges are accumulated on the upper side of the accumulation electrode, then charge storage is achieved, but transfer to the collection electrode below becomes inefficient
Solution Approach 1:
The semiconductor layer is divided into a first region for charge reception from the organic photoelectric conversion film and a second region for charge accumulation and transfer. This segmentation creates efficient charge transfer pathways that maintain both charge accumulation capability and transfer speed, preventing the bottleneck that occurs when charges are only accumulated on the upper side of the accumulation electrode.
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
Improves quantum efficiency by efficiently storing charges in the semiconductor layer, enhancing the device's light detection capabilities.
Implementation Method 1
a photoelectric conversion section disposed on the first semiconductor layer on a side of a first surface
Data Source
AI summary
The quantum efficiency can be improved. A solid-state imaging device according to an embodiment includes: a plurality of pixels arranged in a matrix, in which each of the pixels includes a first semiconductor layer, a photoelectric conversion section disposed on the first semiconductor layer on a side of a first surface, an accumulation electrode disposed on the first semiconductor layer close to a side of a second surface on a side opposite to the first surface, a wiring extending from the second surface of the first semiconductor layer, a floating diffusion region connected to the first semiconductor layer via the wiring, and a first gate electrode disposed close to the wiring.