Image Sensor Gate Electrode Vertical Orientation
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Solution Overview
Problem
Existing image sensors face a challenge in maximizing the light-receiving surface area due to the presence of transfer gate electrodes, which reduces the fill factor and overall performance, especially in stacked photoelectric conversion devices.
Innovation Solution
The image sensor design incorporates a semiconductor photoelectric conversion device with a transfer gate electrode extending perpendicular to the light-receiving surface, while the upper organic photoelectric conversion device lacks a transfer gate electrode, thereby maintaining a large light-receiving surface area and improving fill factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transfer gate electrodes are added to control photoelectric conversion devices, then device functionality and control capability are improved, but light-receiving surface area and fill factor deteriorate
Solution Approach 1:
The gate electrode extends in the vertical direction (perpendicular to the substrate surface) rather than only in the horizontal plane. This three-dimensional configuration allows the gate to control the photoelectric conversion device without occupying excessive horizontal space, thereby maintaining a large light-receiving surface area while providing effective control capability.
2Ease of operation
If transfer gate electrodes are placed over photoelectric conversion devices, then device control is enabled, but fill factor is reduced
Solution Approach 1:
The gate electrode is configured to extend vertically from the substrate surface toward the photoelectric conversion device rather than being placed entirely in the horizontal plane. This vertical extension provides control capability while minimizing the horizontal footprint, thereby maintaining a high fill factor.
3Productivity
If stacked photoelectric conversion devices are implemented, then integration density is improved, but light-receiving surface area is reduced due to wiring and electrodes
Solution Approach 1:
The gate electrode extends in the vertical direction to provide control functionality for the stacked photoelectric conversion devices without occupying horizontal space. This allows the stacked configuration to maintain high integration density while preserving maximum light-receiving surface area.
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 allows for a high degree of integration and accurate light detection across various wavelengths, enhancing the image sensor's performance by maintaining a large light-receiving surface area and preventing reduction caused by wiring and electrode placement.
Implementation Method 1
a semiconductor photoelectric conversion device on the substrate
Implementation Method 2
an organic photoelectric conversion device on the second surface
Data Source
AI summary
An image sensor includes a substrate comprising a first face and a second surface which faces the first surface and on which light is incident, a semiconductor photoelectric conversion device on the substrate, a gate electrode located between the first surface of the substrate and the semiconductor photoelectric conversion device and extending in a first direction perpendicular to the first surface, and an organic photoelectric conversion device stacked on the second surface of the substrate.