Radiation Detector Dual Gate Transistor Threshold Voltage Stability
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Solution Overview
Problem
Existing radiation detectors face challenges in suppressing variation and fluctuation in threshold voltage, which affects the accuracy of radiation detection, particularly in amplifying transistors used in active pixel sensors.
Innovation Solution
A radiation detector design featuring an amplifying transistor with a channel layer and two gate electrodes, where the second gate electrode is set to the same potential as the first gate electrode, functioning as a back gate to stabilize the threshold voltage, and utilizing an oxide semiconductor with a non-amorphous crystal structure, such as indium and zinc, to reduce fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an amplifying transistor is used to detect small amounts of light from radiation, then the detection sensitivity is improved, but the threshold voltage variation increases leading to unstable operation
Solution Approach 1:
The gate electrode is divided into two separate gate electrodes (first gate electrode and second gate electrode) that can be independently controlled. This segmentation allows the first gate to control channel formation while the second gate stabilizes the threshold voltage, resolving the contradiction between sensitivity and stability.
Solution Approach 2:
The invention changes the electrical parameter configuration by applying different potentials to the two gate electrodes. By independently adjusting gate potentials, the system can optimize both detection sensitivity (through channel control) and threshold voltage stability (through potential stabilization), eliminating the trade-off.
2Manufacturing precision
If the light receiving devices are fabricated densely to achieve high-resolution images, then the image resolution is improved, but the light receiving area of each device is reduced
Solution Approach 1:
By using IGZO semiconductor material which has higher carrier mobility and lower leak current, the invention enables smaller transistor dimensions while maintaining performance. This parameter change in material properties allows dense fabrication for high resolution without excessive loss of light receiving 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 stabilizes the threshold voltage of the amplifying transistor, thereby suppressing variation in the amount of radiation detected and ensuring stable operation, enabling high-resolution image capture with a small amount of radiation.
Implementation Method 1
The photodiode 201 converts emitted light into charge
Implementation Method 2
a scintillator that emits light in response to radiation
Data Source
AI summary
[Object] To achieve a radiation detector capable of suppressing variation in the amount of radiation detected.[Solution] A first gate electrode (52) is connected to a light receiving device, and a second gate electrode (53) is configured to have the same potential as that of the first gate electrode (52).