Solid-State Image Sensor Layout for Charge-Holding Noise Reduction
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Solution Overview
Problem
Solid-state imaging devices face noise issues due to light entering the charge holding section, which existing technologies have not adequately addressed.
Innovation Solution
A solid-state imaging device with a light blocking section and a charge blocking section is designed, where the light blocking section has an opening for the vertical gate electrode and blocks light entry into the charge holding section at parts other than the opening, and the charge blocking section isolates the light blocking section and vertical gate electrode, reducing light entry and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light blocking section is provided between the photoelectric converter and charge holding section, then light entry into the charge holding section is blocked, but noise reduction is insufficient
Solution Approach 1:
The light blocking section is divided into a first light blocking section and a second light blocking section positioned at different locations. The first light blocking section blocks light from specific directions, while the second light blocking section blocks light from other directions, together providing comprehensive light blocking coverage that significantly reduces noise in the charge holding section
Solution Approach 2:
Different regions of the light blocking section are designed with different blocking characteristics. The first light blocking section has specific geometric features optimized for blocking light from certain angles, while the second light blocking section has different features optimized for other angles, creating localized blocking quality that collectively eliminates light entry from all directions
2Object-affected harmful factors
If the light blocking section completely covers the opening, then light blocking is maximized, but electric charge transfer is blocked
Solution Approach 1:
An opening is extracted from the light blocking section to allow electric charge to pass through from the photoelectric converter to the charge holding section. This opening is strategically positioned and sized to permit charge transfer while the surrounding light blocking sections block light from entering through the opening
Solution Approach 2:
The opening acts as an intermediary structure that mediates between the conflicting requirements of light blocking and charge transfer. It allows electric charge to pass through while the light blocking sections surrounding the opening prevent light from using the same path, effectively decoupling the light and charge pathways
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 noise in the charge holding section by blocking light and isolating components, improving the imaging device's performance.
Implementation Method 1
The light blocking section has an opening which the vertical gate electrode runs through, and blocks entry, into the charge holding section, of light entering via the light receiving surface at a part other than the opening
Implementation Method 2
The photoelectric converter performs photoelectric conversion on light entering via the light receiving surface
Data Source
AI summary
A solid-state imaging device according to an embodiment of the present disclosure includes two or more pixels. The pixels each include a photoelectric converter, a charge holding section, and a transfer transistor. The charge holding section holds electric charge transferred from the photoelectric converter. The transfer transistor transfers electric charge from the photoelectric converter to the charge holding section. The pixels each further include a light blocking section that is disposed in a layer between the photoelectric converter and the charge holding section. The light blocking section has an opening which a vertical gate runs through. The pixels each further include a charge blocking section that blocks transfer of electric charge to the transfer transistor via a region between an edge, of the opening, closer to the charge holding section and the vertical gate.