Solid-State Imaging Device Trench Isolation Optical Crosstalk
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Solution Overview
Problem
Solid-state imaging devices face challenges in increasing dynamic range while maintaining smaller pixel sizes, which leads to increased optical crosstalk due to reduced pixel size.
Innovation Solution
The implementation of a solid-state imaging device with a pixel array unit and a drive unit that includes trench-type charge storage units between photoelectric conversion units, along with reverse-side deep trench isolation, to reduce optical crosstalk and enhance dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel size is reduced to increase the number of pixels, then productivity and resolution are improved, but optical crosstalk between adjacent pixels increases
Solution Approach 1:
The patent divides the pixel array into isolated unit pixels by introducing deep trench isolation structures between adjacent pixels. This segmentation physically separates the photoelectric conversion regions, preventing optical crosstalk while maintaining high pixel density. The trench isolation acts as a barrier that segments the continuous semiconductor substrate into discrete pixel units.
Solution Approach 2:
The patent introduces an intermediary deep trench isolation structure between adjacent photoelectric conversion units. This intermediary element (the trench filled with insulating material) acts as a mediator that blocks optical signals from crossing between adjacent pixels, thereby eliminating crosstalk while allowing the pixels to remain closely spaced for high resolution.
2Measurement precision
If pixel size is reduced to increase dynamic range, then measurement precision is improved, but optical crosstalk increases
Solution Approach 1:
The deep trench isolation structures segment the pixel array into electrically and optically isolated units. This segmentation allows each pixel to maintain its photoelectric conversion characteristics independently, preserving measurement precision and dynamic range while preventing crosstalk that would otherwise degrade these parameters.
Solution Approach 2:
The trench isolation serves as an intermediary barrier between adjacent pixels, blocking the propagation of optical signals that would cause crosstalk. This intermediary structure enables small pixel sizes to maintain high measurement precision by preventing interference from neighboring pixels.
3Area of stationary object
If pixel size is reduced, then area efficiency is improved, but linearity deteriorates due to optical crosstalk
Solution Approach 1:
The patent employs deep trench isolation to segment the semiconductor substrate into discrete pixel regions. This segmentation maintains area efficiency by allowing tight pixel packing while preserving linearity through the isolation barriers that prevent optical crosstalk from distorting the photoelectric conversion characteristics.
Solution Approach 2:
The trench isolation acts as an intermediary structure that maintains the optical independence of each pixel. This allows the pixel array to achieve high area efficiency with small pixel sizes while the intermediary trenches preserve linearity by blocking crosstalk that would otherwise cause non-linear response.
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 effectively reduces optical crosstalk and increases the dynamic range of the imaging device, improving linearity and reducing the impact of smaller pixel sizes on image quality.
Implementation Method 1
a photoelectric conversion unit; charge generated by the photoelectric conversion unit
Data Source
AI summary
The present disclosure relates to a solid-state imaging device and an electronic apparatus which allow reduction of optical crosstalk. In an example of FIG. 5B, a charge storage unit is formed by a method in which a hole is bored in a substrate, a diffusion layer is formed in a surface of the hole, and an insulating film and an upper electrode are formed so as to fill the hole. In an example of FIG. 5C, a charge storage unit is formed by a method in which a hole is bored in a substrate, a diffusion layer is formed in a half (one side) of a surface of the hole, and an insulating film and an upper electrode are formed so as to fill the hole. The present disclosure can be applied to a CMOS solid-state imaging device used for an imaging apparatus such as a camera, for example.