Quantum Dot Image Sensor Structure for Low-Noise Small Pixels
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Solution Overview
Problem
As image sensors increase in resolution, pixel size decreases, leading to reduced light-receiving regions, increased dark noise, and lower signal-to-noise ratios due to reduced photon incidence, making it difficult to obtain clear images.
Innovation Solution
The use of quantum dots as a light-absorbing material in opto-electronic devices, combined with a bank structure formed from inorganic materials, such as SiO2, Si3N4, or Al2O3, to create a light-receiving region with a quantum dot layer that enhances light absorption and reduces electrical connections, thereby improving signal-to-noise ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to increase resolution, then image resolution is improved, but light-receiving region is reduced and signal-to-noise ratio deteriorates
Solution Approach 1:
The patent changes the material parameter of the light-absorbing layer from conventional materials to quantum dots, which have unique size-dependent optical properties. By controlling quantum dot size (2-50 nm), the light absorption characteristics can be tuned to enhance light-receiving efficiency in reduced pixel sizes while maintaining low dark noise, thus resolving the contradiction between resolution and signal-to-noise ratio
Solution Approach 2:
The patent employs a composite structure combining quantum dots with semiconductor materials (such as Si, Ge, or compound semiconductors) to create a hybrid light-absorbing layer. This composite approach leverages the high quantum efficiency of quantum dots and the mature semiconductor processing technology, enabling both high resolution and low dark noise performance
2Measurement precision
If pixel size is reduced to increase resolution, then image resolution is improved, but dark noise increases
Solution Approach 1:
The patent utilizes the quantum confinement effect by changing the size parameter of quantum dots (2-50 nm) to optimize light absorption while inherently suppressing dark noise generation. The quantum dot structure provides discrete energy levels that reduce thermal generation of carriers, thereby lowering dark noise even in small pixels
Solution Approach 2:
The patent introduces quantum dots as an intermediary material between the incident light and the semiconductor substrate. This intermediary layer enhances light absorption efficiency while its unique quantum structure suppresses dark noise, acting as a mediator that decouples the trade-off between pixel size and noise performance
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 achieves low dark noise and high signal-to-noise ratios by increasing light-receiving efficiency and amplifying photocurrent, allowing for clear image capture even with weak incident light, while enabling further reduction in pixel size for higher resolution.
Implementation Method 1
a quantum dot layer provided between the first electrode and the second electrode on the base portion, the quantum dot layer including a plurality of quantum dots
Implementation Method 2
a bank structure covering at least a first partial region of the first electrode and at least a second partial region of the second electrode, the bank structure defining a region where the quantum dot layer is formed
Data Source
AI summary
An opto-electronic device includes a base portion, a first electrode and a second electrode formed on an upper surface of the base portion apart from each other, a quantum dot layer, and a bank structure. The quantum dot layer is between the first electrode and the second electrode on the base portion and includes a plurality of quantum dots. The bank structure covers at least partial regions of the first electrode and the second electrode, defines a region where the quantum dot layer is formed, and is formed of an inorganic material.