Asymmetric Transistor Sensor for X-ray Detection
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Solution Overview
Problem
Current digital sensor devices used for X-ray detection face challenges in reducing X-ray irradiation dose due to limitations in signal-to-noise ratio (SNR), which affects detection accuracy and safety.
Innovation Solution
The design of a sensor device incorporating an asymmetric transistor structure with specific semiconductor layers and transistors, including poly-silicon and oxide semiconductor materials, to enhance the SNR and detection accuracy by mitigating short channel effects and improving uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional photodiode-based digital sensor device is used, then X-ray detection function is achieved, but signal-to-noise ratio is limited and detection accuracy is insufficient
Solution Approach 1:
The patent applies asymmetry principle by designing an asymmetric transistor structure where the first drain has a concave surface and the first source is disposed corresponding to the concave surface. This asymmetric geometry optimizes the electric field distribution and carrier collection efficiency, thereby improving the signal-to-noise ratio and detection accuracy of the sensor device.
Solution Approach 2:
The patent implements local quality principle by using different semiconductor materials for different transistor regions. Specifically, at least one of the first, second, or third semiconductor layers includes poly-silicon, while at least another includes oxide semiconductor or amorphous silicon. This material differentiation optimizes local electrical properties to enhance overall detection performance.
2Object-affected harmful factors
If X-ray irradiation dose is reduced to prevent over irradiation, then safety is improved, but signal-to-noise ratio deteriorates and detection accuracy decreases
Solution Approach 1:
The asymmetric transistor structure with concave first drain surface optimizes carrier collection efficiency, enabling the sensor to maintain high detection accuracy even at lower X-ray irradiation doses. This allows safety improvement without sacrificing measurement precision.
Solution Approach 2:
The patent changes the structural parameters of the transistor by introducing the concave surface geometry and using different semiconductor materials (poly-silicon, oxide semiconductor, amorphous silicon) in different regions. These parameter changes enhance the sensor's sensitivity and signal-to-noise ratio, allowing accurate detection at reduced X-ray doses.
3Ease of manufacture
If symmetric transistor structure is used, then manufacturing is simplified, but short channel effects increase and uniformity deteriorates
Solution Approach 1:
The patent deliberately introduces asymmetry in the transistor structure by making the first drain have a concave surface while the source has a corresponding convex surface. This asymmetric design counteracts short channel effects and improves uniformity of electrical characteristics across the device, while still being manufacturable using standard semiconductor fabrication processes.
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
The solution effectively increases the signal-to-noise ratio and detection accuracy of the sensor device, reducing the X-ray irradiation dose and enhancing the uniformity of detection, thereby improving the safety and effectiveness of X-ray imaging.
Implementation Method 1
the photosensor is coupled to the first gate
Data Source
AI summary
A sensor device is provided and includes a first transistor, a second transistor, a third transistor, and a photosensor. The first transistor has a first gate, a first drain, and a first source. The first drain is coupled to a first power line and has a concave surface, and the first source is disposed corresponding to the concave surface. The second transistor has a second source, coupled to the first gate. The third transistor has a third gate, a third drain, and a third source, the third drain is coupled to the first source, the third source is coupled to the data line, and the third gate is coupled to the readout line. The photosensor is coupled to the first gate.