Image Sensor Conductive Pixel Separation Structure for Crosstalk Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Highly integrated image sensors face challenges with reduced pixel size, leading to increased risk of crosstalk, which affects their performance and image quality.
Innovation Solution
The implementation of a conductive layer with a mesh structure in a pixel separation structure, along with a voltage-applying wire layer and inner wire layer, helps to separate pixels and improve dark current characteristics by applying a negative voltage, thereby reducing crosstalk and enhancing image sensor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel size is reduced to increase integration, then device integration is improved, but crosstalk between pixels increases
Solution Approach 1:
The pixel separation structure divides the substrate into isolated pixel regions using conductive layers arranged in grid patterns. This segmentation physically separates adjacent pixels, preventing optical and electrical crosstalk while maintaining high pixel density and integration.
Solution Approach 2:
Conductive layers are introduced as intermediary elements between adjacent pixels. These layers act as barriers that block crosstalk while allowing the photodiodes to function independently, thus enabling high integration without sacrificing signal isolation.
2Productivity
If pixel size is reduced to increase integration, then device integration is improved, but image quality deteriorates
Solution Approach 1:
By segmenting the pixel array with conductive separation layers, each pixel maintains its optical independence despite reduced size. This ensures that image quality is preserved through proper signal isolation, preventing degradation from crosstalk even as integration increases.
Solution Approach 2:
The conductive layers modify the electrical parameters of the pixel structure by establishing proper potential distribution. This controls charge carrier movement and reduces dark current, thereby maintaining image quality parameters despite smaller pixel dimensions.
3Object-affected harmful factors
If conductive layer is added to pixel separation structure, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The conductive layers are merged with the existing pixel separation structure during fabrication. By integrating the crosstalk reduction function into the separation structure itself, the design avoids adding separate complex components, thus reducing overall device complexity while still achieving crosstalk suppression.
4Reliability
If voltage-applying wire layer is added, then dark current characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The voltage-applying wire layer serves multiple functions: it controls dark current characteristics, establishes electrical potential distribution, and provides a pathway for charge management. This multi-functionality reduces the need for separate structures, thereby simplifying manufacturing despite the added functionality.
Solution Approach 2:
The wire layer is positioned in the vertical dimension above the pixel array, allowing voltage application without interfering with the horizontal pixel layout. This dimensional separation enables dark current control while maintaining manufacturing simplicity through standardized layer deposition processes.
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 solution effectively reduces crosstalk between pixels, improves dark current characteristics, and maintains image quality by ensuring proper voltage application and charge management within the image sensor.
Implementation Method 1
a pixel separation structure arranged in the substrate to separate the pixels from each other and comprising a conductive layer therein
Implementation Method 2
a voltage-applying wire layer spaced apart from the conductive layer and arranged on the substrate to surround at least a portion of an outer portion of the pixel area, wherein the voltage-applying wire layer is electrically connected to the conductive layer through at least one contact
Implementation Method 3
Each of the pixels includes a photodiode (PD). The PD converts light incident thereto into an electrical signal
Data Source
AI summary
An image sensor includes a first pixel separation structure in a substrate to separate pixels from each other. The first pixel separation structure includes a conductive layer therein. Moreover, the image sensor includes a wire layer that is spaced apart from the conductive layer on the substrate. A second pixel separation structure is adjacent to the first pixel separation structure in a first horizontal direction and is connected to a contact. The first and second pixel separation structures extend longitudinally in a second horizontal direction that is perpendicular to the first horizontal direction.