Solid-State Imaging Device Sidewall Configuration
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Solution Overview
Problem
The existing solid-state imaging devices face damage and defects in the pixel region due to the anisotropic etching process used to form sidewalls on gate electrodes, which can lead to substrate damage and image quality degradation.
Innovation Solution
A solid-state imaging device structure where sidewalls are only formed on the gate electrodes in the peripheral region, avoiding etching in the pixel region to prevent substrate damage, and utilizing a specific impurity layer configuration to control threshold voltage and enhance modulation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anisotropic etching is performed to form sidewalls on gate electrodes in the pixel region, then transistor characteristics are improved, but substrate damage occurs and defects are generated
Solution Approach 1:
The patent applies different structural configurations to different regions: sidewalls are formed on gate electrodes in the peripheral region to improve transistor characteristics, while no sidewalls are formed in the pixel region to avoid substrate damage. This regional differentiation resolves the contradiction by optimizing each region according to its specific requirements.
2Reliability
If sidewalls are formed on all gate electrodes, then device characteristics are improved, but manufacturing complexity increases due to additional etching processes
Solution Approach 1:
The invention selectively forms sidewalls only in the peripheral region where they are needed for transistor performance, while omitting them in the pixel region. This reduces the number of etching steps required compared to forming sidewalls everywhere, thereby reducing manufacturing complexity while maintaining device characteristics where necessary.
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 prevents defects in the pixel region, maintains image quality, and reduces power consumption while ensuring reliable operation by avoiding substrate damage during the etching process.
Implementation Method 1
a photoelectric conversion element and a modulation part formed adjacent to the photoelectric conversion element
Implementation Method 2
The threshold voltage of the transistor 112 changes by photo-generated charges accumulated in the carrier pocket 117
Data Source
AI summary
A solid-state imaging device includes: a photoelectric conversion element; a pixel region including a modulation part formed adjacent to the photoelectric conversion element; and a peripheral region in which a peripheral circuit including a driving circuit driving the photoelectric conversion element and the modulation part is disposed, wherein the peripheral region includes a transistor that a sidewall is formed on a side of a gate electrode; and the pixel region includes a transistor that no sidewall is formed on a side of a gate electrode.