Dual-Gate Thin Film Transistor for Stable Photosensitive Devices
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Solution Overview
Problem
Current photosensitive devices for optical fingerprint recognition and X-ray detection technologies face challenges in optimizing the structure and manufacturing processes of photosensitive elements and thin film transistors to enhance performance.
Innovation Solution
A photosensitive device is designed with a dual-gate thin film transistor structure and a photoelectric conversion layer, where the first electrode layer and second gate electrode are formed in the same layer, and the active layer includes a source region, drain region, and channel region, with an interlayer insulating layer having specific thickness and recesses to improve stability and uniformity of the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-gate thin film transistor structure is used, then the manufacturing process is simpler, but the stability and uniformity of the threshold voltage are insufficient
Solution Approach 1:
The thin film transistor is divided into two independent gate electrodes (first gate electrode and second gate electrode) that can be controlled separately. This segmentation allows independent optimization of threshold voltage and channel control, resolving the contradiction by enabling precise control of electrical characteristics while maintaining a modular structure that doesn't excessively complicate manufacturing
Solution Approach 2:
The dual-gate structure serves multiple functions: the first gate electrode controls the threshold voltage, while the second gate electrode controls the channel current. This multi-functionality allows a single device structure to address both stability and uniformity requirements simultaneously, improving reliability without requiring multiple separate components
2Area of stationary object
If the first electrode layer and second gate electrode are formed in different layers, then the manufacturing process is simpler, but the device area increases and integration density decreases
Solution Approach 1:
The patent utilizes the vertical dimension by stacking the first electrode layer and second gate electrode in different vertical positions (z-dimension) rather than placing them side-by-side in the same plane. This dimensional transition reduces the horizontal footprint of the device while maintaining manufacturing simplicity through sequential layer deposition processes
3Measurement precision
If light irradiation on the channel region is not reduced, then the device structure is simpler, but the performance and detection accuracy deteriorate
Solution Approach 1:
The patent extracts and isolates the channel region from excessive light irradiation by using the second gate electrode and interlayer insulating layer as protective structures. This extraction of the channel region from harmful light exposure improves detection accuracy by reducing noise and interference, while the protective structures are integrated into the existing device architecture rather than adding significant complexity
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 dual-gate structure and oxide semiconductor active layer enhance the stability and uniformity of the thin film transistor, leading to improved performance of the photosensitive device, including enhanced light detection and reduced light irradiation on the channel region.
Implementation Method 1
The photosensitive element may convert visible light into electrical signals
Data Source
AI summary
A photosensitive device, a manufacturing method thereof, a detection substrate and an array substrate are provided. The photosensitive device is formed on a substrate, and it includes a photosensitive element and a thin film transistor. The photosensitive element includes a first electrode layer on the substrate; a second electrode layer on a side of the first electrode layer distal to the substrate; and a photoelectric conversion layer between the first electrode layer and the second electrode layer. The thin film transistor is electrically connected to the photosensitive element, and it includes a first gate electrode on the substrate; an active layer on a side of the first gate electrode distal to the substrate; and a second gate electrode on a side of the active layer distal to the substrate. The first electrode layer and the second gate electrode are located in the same layer.