Image Sensor Light Blocking Structure for Leakage Current Noise
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Solution Overview
Problem
Image sensors face challenges with high leakage current and noise due to the lack of effective light blocking mechanisms, which affect their performance in converting optical information into electrical signals.
Innovation Solution
Incorporating a light blocking layer made of metal oxide semiconductor material between the photoelectric conversion layer and the transistor structure, which blocks incident light and reduces noise, thereby improving the image sensor's performance by minimizing contact leakage current and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light blocking layer is added to block incident light and reduce noise, then noise and leakage current are reduced, but device complexity increases
Solution Approach 1:
The light blocking layer is nested within the existing sensor structure, positioned between the photoelectric conversion layer and the transistor structure. This nesting approach integrates the light blocking function into the existing layers without requiring separate external blocking components, thereby reducing overall device complexity while maintaining effective noise reduction.
Solution Approach 2:
The light blocking layer acts as an intermediary element between the photoelectric conversion layer and the transistor structure. It mediates the interaction by blocking stray light from reaching the transistor while allowing the photoelectric conversion process to continue uninterrupted, thus reducing noise without fundamentally altering the primary photoelectric conversion function.
2Object-affected harmful factors
If a light blocking layer is disposed close to the photoelectric conversion layer, then light blocking effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
The light blocking layer is merged with the transistor structure by disposing it between the photoelectric conversion layer and the transistor structure. This merging allows the light blocking function to be achieved at a moderate distance from the photoelectric conversion layer, reducing the stringent positioning precision requirements while maintaining effective light blocking through the combined structural arrangement.
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
The implementation of a light blocking layer effectively reduces leakage current and noise, enhancing the image sensor's performance and accuracy in converting optical signals into electrical signals.
Implementation Method 1
A light blocking layer may be disposed between the third surface and the photoelectric conversion layer, and spaced from the photoelectric conversion layer
Implementation Method 2
a photoelectric conversion layer which generates photocharges from light incident in a first direction
Data Source
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AI summary
An image sensor may include a substrate having a first surface and a second surface on opposite sides, a first transistor having a first gate disposed on the first surface, a photoelectric conversion layer which generates photocharges from light incident in a first direction, a second transistor having a transistor structure disposed between the first surface and the photoelectric conversion layer and spaced from the photoelectric conversion layer, and includes a semiconductor layer composed of a metal oxide semiconductor material. The semiconductor layer may have a third surface facing the first direction and a fourth surface opposite the third surface, with a second gate disposed on the semiconductor layer. The semiconductor layer may be connected to the first gate. A light blocking layer may be disposed between the third surface and the photoelectric conversion layer, and spaced from the photoelectric conversion layer.