Curved Convex Photodiode Structure for Image Sensor Sensitivity
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Solution Overview
Problem
Current image sensors face challenges with reduced pixel size, leading to decreased signal intensity, sensitivity, and increased crosstalk due to smaller light-receiving areas and optical losses.
Innovation Solution
The implementation of a stacked structure with curved convex photodiode elements and a micro-lens system, which increases the effective light-receiving area without expanding the device's projection area, enhancing sensitivity and external quantum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If pixel size is reduced to increase resolution, then device integration is improved, but signal intensity and sensitivity decrease
Solution Approach 1:
The patent transitions from a planar 2D photodiode structure to a 3D curved convex structure. The photodiode layer is formed with a curved surface having a predetermined radius of curvature, creating a three-dimensional light-receiving surface that extends beyond the planar constraint. This dimensional change allows increased light-receiving area within the same pixel footprint, thereby maintaining signal intensity despite pixel size reduction.
Solution Approach 2:
The patent explicitly employs curvature by forming the photodiode layer with a curved convex surface instead of a flat surface. The curved structure has a predetermined radius of curvature that maximizes the light-receiving area. This spherical/curved geometry allows photons to be captured from a wider angular range and increases the effective area without increasing the planar projection area, resolving the contradiction between small pixel size and sufficient signal intensity.
2Area of moving object
If pixel size is reduced, then device integration is improved, but sensitivity decreases
Solution Approach 1:
By forming the photodiode layer in a curved convex shape rather than a flat plane, the invention creates additional light-receiving surface area in the vertical dimension. This 3D structure allows more photons to be captured within the same lateral pixel dimensions, thereby maintaining sensitivity even as pixel size decreases for higher integration density.
Solution Approach 2:
The curved surface of the photodiode layer with predetermined radius of curvature increases the effective light-receiving area compared to a planar structure. This curvature allows the photodiode to capture light from multiple angles and increases the interaction path length, enhancing sensitivity without requiring larger pixel dimensions.
3Ease of manufacture
If planar structure is used, then manufacturing is simple, but light-receiving area is limited
Solution Approach 1:
The invention moves from a two-dimensional planar photodiode layer to a three-dimensional curved convex structure. This dimensional transition increases the light-receiving area by utilizing the vertical dimension and curved surface geometry, while the manufacturing process remains relatively straightforward by forming the curved layer directly during the semiconductor fabrication process.
Solution Approach 2:
The curved convex structure of the photodiode layer provides increased light-receiving area compared to a flat planar structure. The curvature is designed with a predetermined radius that optimizes light capture while the structure can be manufactured using standard semiconductor processing techniques, balancing manufacturing simplicity with enhanced light-receiving capability.
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 approach improves signal intensity and sensitivity while maintaining a conventional design, simplifying the manufacturing process and reducing crosstalk, even at smaller pixel sizes.
Implementation Method 1
a photodiode device portion arranged on the color filter layer, the photodiode device portion including a plurality of curved convex structures respectively corresponding to the plurality of color filters
Implementation Method 2
Embodiments propose a stacked structure which may increase a light receiving area and thus improve (i.e. increase) sensor sensitivity. The stacked structure may provide a spherical structure (rather than a planar structure) which increases the size of a light receiving area without increasing a projection (i.e. plan) area.
Data Source
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AI summary
Provided are an image sensor and a method of manufacturing the same. The image sensor may include a plurality of light detection elements arranged to correspond to a plurality of pixel regions, a color filter layer on the plurality of light detection elements and including a plurality of color filters arranged to correspond to the plurality of light detection elements, and a photodiode device portion on the color filter layer. The photodiode device portion may have curved structures. The photodiode device portion may include an organic material-based photodiode layer, a first electrode between the photodiode layer and the color filter layer, and a second electrode on the photodiode layer. The photodiode device portion may have curved convex structures respectively corresponding to the plurality of color filters.