Oxide Semiconductor Imaging Pixel Charge Transfer
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Solution Overview
Problem
Imaging devices using the global shutter method face complexity in charge transfer efficiency, circuit configuration, and data retention, particularly when trying to capture images of moving objects without distortion while maintaining high light sensitivity and resolution.
Innovation Solution
The imaging device incorporates a specific structure with conductors and insulators to enhance charge transfer efficiency, utilizing an oxide semiconductor with In, Zn, and M (Al, Ga, Y, or Sn) for improved light sensitivity and a simple circuit configuration, allowing for efficient data retention and high-resolution imaging of moving objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a data retention portion is provided to retain imaging data for long time, then data retention capability is improved, but circuit configuration becomes more complicated
Solution Approach 1:
The patent combines the data retention function with the pixel structure itself by forming an embedded channel region through impurity addition in the semiconductor layer. This integration eliminates the need for separate data retention circuits, achieving long-term data retention while maintaining a simple circuit configuration.
Solution Approach 2:
The semiconductor layer serves multiple functions: it acts as both the active pixel region for light detection and the data retention portion through the embedded channel region. This multi-functionality reduces the overall circuit complexity while enabling long-term charge storage capability.
2Measurement precision
If a transfer gate is provided in the data retention portion for accurate readout, then readout accuracy is improved, but device structure becomes more complicated
Solution Approach 1:
The transfer gate is integrated into the existing pixel structure by forming the embedded channel region within the semiconductor layer. This merging approach enables accurate charge transfer and readout without adding separate, complex transfer gate structures, thus maintaining readout accuracy while simplifying the overall device structure.
3Productivity
If transfer gate overlaps gate electrode to increase charge transfer efficiency, then charge transfer efficiency is improved, but manufacturing process becomes more complicated
Solution Approach 1:
The patent merges the transfer gate function with the existing gate electrode structure by forming the embedded channel region in the semiconductor layer. This integration achieves high charge transfer efficiency without requiring complex overlapping structures, thereby simplifying the manufacturing process while maintaining productivity.
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 enables efficient charge transfer, high light sensitivity, and a simple circuit design, allowing for distortion-free imaging of moving objects with long data retention and high resolution, while also simplifying the manufacturing process and reducing costs.
Implementation Method 1
a first photoelectric conversion element
Data Source
AI summary
An object is to provide an imaging device with high efficiency of transferring charge corresponding to imaging data. The imaging device includes first to fifth conductors, first and second insulators, an oxide semiconductor, a photoelectric conversion element, and a transistor. The first conductor is in contact with a bottom surface and a side surface of the first insulator. The first insulator is in contact with a bottom surface of the oxide semiconductor. The oxide semiconductor is in contact with bottom surfaces of the second and third conductors and the second insulator. Each of the second and third conductors is in contact with the bottom surface and a side surface of the second insulator. The second insulator is in contact with bottom surfaces of the fourth and fifth conductors. The first conductor has regions overlapped by the fourth and fifth conductors. The second conductor has a region overlapped by the fourth conductor. The third conductor has a region overlapped by the fifth conductor. The second conductor is electrically connected to one electrode of the photoelectric conversion element. The third conductor is electrically connected to a gate of the transistor.