Organic Image Sensor Transistor Segmentation for Leakage Reduction
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Solution Overview
Problem
Current image sensors face challenges in achieving high performance and integration while maintaining low noise and preventing leakage currents, particularly in the context of backside illumination type image sensors with organic photoelectric conversion layers.
Innovation Solution
The design incorporates a substrate with a first organic photoelectric conversion layer, a penetration via, a floating diffusion region, and a transistor structure with a semiconductor layer, gate electrode, and gate dielectric film, which improves light reception efficiency and reduces noise by spacing the transistor structure apart from the substrate, enhancing integration and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transistor structure is integrated closely with the substrate to increase integration density, then device complexity is reduced and integration is improved, but leakage currents increase and noise is generated
Solution Approach 1:
The transistor structure is segmented from the substrate by introducing an interlayer insulating film between them. This segmentation allows the transistor to be electrically isolated from the substrate, preventing leakage currents while maintaining integration. The semiconductor layer is divided into distinct regions (first semiconductor layer connected to penetration via, second semiconductor layer connected to floating diffusion region) separated by the insulating film.
Solution Approach 2:
An interlayer insulating film is introduced as an intermediary between the transistor structure and the substrate. This intermediary layer electrically isolates the two components, preventing direct contact that would cause leakage currents. The insulating film acts as a mediator that allows integration while blocking harmful electrical leakage.
2Device complexity
If the transistor structure is integrated closely with the substrate to improve integration, then device complexity is reduced, but noise is generated affecting image quality
Solution Approach 1:
The transistor structure is segmented from the substrate using an interlayer insulating film, creating electrical isolation that prevents noise generation from direct contact. The segmentation maintains integration benefits while eliminating the harmful noise effect through physical and electrical separation.
Solution Approach 2:
The interlayer insulating film serves as an intermediary that electrically isolates the transistor from the substrate, preventing noise generation. This intermediary layer allows the structures to remain integrated in the same device while blocking the harmful noise interaction.
3Ease of manufacture
If a conventional semiconductor photoelectric conversion layer is used, then manufacturing is straightforward, but light-receiving efficiency and optical sensitivity are insufficient
Solution Approach 1:
The photoelectric conversion layer uses organic semiconductor materials with specific molecular structures (such as triphenylamine derivatives) that provide superior light-receiving efficiency and optical sensitivity compared to conventional inorganic materials. The composite structure combines organic photoelectric conversion materials with the substrate and transistor structures, achieving high performance while maintaining manufacturability through solution processing techniques.
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 results in improved image sensor performance with reduced noise and increased integration, enabling effective conversion of optical signals into electric signals with enhanced light-receiving efficiency.
Implementation Method 1
image sensor including an organic photoelectric conversion layer... convert optical information into electric signals
Data Source
AI summary
Image sensors with improved performance and a higher degree of integration are provided. The image sensors include a substrate including a first surface and a second surface opposite to each other, a first organic photoelectric conversion layer on the first surface of the substrate, a first penetration via connected to the first organic photoelectric conversion layer and extending through the substrate, a first floating diffusion region in the substrate adjacent to the second surface of the substrate, and a first transistor structure on the second surface of the substrate, wherein the first transistor structure includes a semiconductor layer configured to connect the first penetration via and the first floating diffusion region, a gate electrode on the semiconductor layer, and a gate dielectric film between the semiconductor layer and the gate electrode.