Image Sensor Pixel Stacking for Visible and Infrared Detection
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Solution Overview
Problem
Existing image sensors face challenges in improving light sensitivity and quantum efficiency, particularly for visible and infrared light detection structures, which are essential for advanced applications like 3D imaging and augmented reality.
Innovation Solution
The image sensor design incorporates both visible and infrared light detection structures within the same pixel region, utilizing a semiconductor substrate with isolation structures and epitaxial materials to enhance light sensitivity and quantum efficiency, where a portion of the visible light detection structure overlaps the infrared light detection structure, optimizing their performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visible light detection structure and infrared light detection structure are disposed in separate pixel regions, then each detection structure can be optimized independently, but the pixel region area increases and light sensitivity decreases
Solution Approach 1:
The patent combines visible light detection structure and infrared light detection structure within the same pixel region, allowing both detection functions to coexist in a shared space. This merging approach increases light sensitivity by utilizing the same pixel region for multiple detection purposes while maintaining independent optimization capabilities for each detection structure through strategic spatial arrangement.
Solution Approach 2:
The patent utilizes vertical stacking and overlapping arrangements of detection structures within the pixel region, transitioning from a two-dimensional planar layout to a three-dimensional spatial configuration. This dimensional change allows both visible and infrared detection structures to occupy different vertical zones and spatial layers, enabling independent optimization while sharing the same pixel region footprint.
2Measurement precision
If detection structures are made larger to improve light sensitivity, then quantum efficiency increases, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs a nested arrangement where visible light detection structure and infrared light detection structure are positioned to overlap and interleave within the same pixel region. This nesting configuration allows both structures to share common support elements, isolation structures, and connection pathways, thereby achieving high quantum efficiency for both detection types while reducing overall structural complexity and manufacturing difficulty.
3Measurement precision
If multiple detection structures are integrated in the same pixel region, then light sensitivity and quantum efficiency improve, but the difficulty of detecting and measuring individual signals increases
Solution Approach 1:
The patent divides the pixel region into distinct functional zones with dedicated isolation structures that physically and electrically separate the visible light detection structure from the infrared light detection structure. This segmentation enables independent signal readout and processing for each detection type, maintaining high light sensitivity and quantum efficiency while simplifying signal detection and measurement by preventing cross-interference between the two detection structures.
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 enhances the light sensitivity and quantum efficiency of the image sensor, allowing for improved resolution and performance in capturing both visible and infrared light, even within limited pixel dimensions, thereby supporting advanced imaging applications.
Implementation Method 1
a visible light detection structure and an infrared light detection structure are disposed within one of the pixel regions
Data Source
AI summary
An image sensor includes a semiconductor substrate, a first isolation structure, a visible light detection structure, and an infrared light detection structure. The semiconductor substrate has a first surface and a second surface opposite to the first surface in a vertical direction. The first isolation structure is disposed in the semiconductor substrate for defining pixel regions in the semiconductor substrate. The visible light detection structure and the infrared light detection structure are disposed within the same pixel region, and a first portion of the visible light detection structure is disposed between the second surface of the semiconductor substrate and the infrared light detection structure in the vertical direction.