Oxide-Layer Detection Substrate for Stable X-Ray Flat Panel TFTs
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Solution Overview
Problem
Traditional X-ray flat panel detectors using amorphous silicon TFTs suffer from low mobility, large intrinsic size, resulting in low frame rates and pixel filling rates, and are prone to instability due to hydrogen plasma diffusion during PIN film deposition.
Innovation Solution
A detection substrate with a base substrate, sequentially arranged pixel units comprising a transistor, an oxide layer, a reading electrode, and a photoelectric conversion structure, where the oxide layer acts as a sacrificial layer to prevent hydrogen plasma penetration and enhance transistor stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous silicon TFTs are used in the detection substrate, then the device can be manufactured with existing technology, but the transistor mobility is low and the intrinsic size is large, resulting in low frame rates and pixel filling rates
Solution Approach 1:
The patent changes the material parameter of the transistor from amorphous silicon to oxide semiconductor (such as IGZO), which fundamentally alters the electrical characteristics including mobility and threshold voltage. This material substitution enables higher transistor mobility without requiring changes to the basic manufacturing process flow, thus resolving the contradiction between ease of manufacture and productivity
Solution Approach 2:
The patent employs a composite structure combining oxide semiconductor layers with traditional TFT architecture, integrating the advantages of both approaches. The oxide semiconductor active layer is combined with conventional gate structures and contact layers, creating a hybrid device that maintains manufacturability while achieving superior electrical performance and higher frame rates
2Device complexity
If amorphous silicon TFTs are used in the detection substrate, then the device structure can be simplified, but the transistors are prone to instability due to hydrogen plasma diffusion during PIN film deposition
Solution Approach 1:
The patent introduces an oxide layer as an intermediary barrier between the transistor channel and the hydrogen plasma environment. This oxide layer acts as a protective mediator that prevents hydrogen diffusion into the transistor structure during PIN film deposition, thereby maintaining transistor stability without adding significant structural complexity
Solution Approach 2:
The oxide layer functions as a sacrificial or protective layer that can be optimized for a specific purpose (preventing hydrogen diffusion) rather than requiring the entire transistor structure to be complex and highly durable. This approach prioritizes reliability at a specific critical interface while keeping the overall device structure simple
3Reliability
If the oxide layer is positioned to cover the transistor, then hydrogen plasma penetration is prevented and transistor stability is enhanced, but the electrical connection between reading electrode and transistor must be achieved through the oxide layer
Solution Approach 1:
The oxide layer is segmented with through-holes that are strategically positioned to allow electrical connections while maintaining coverage over the transistor channel. This segmentation enables the oxide layer to simultaneously provide protection and facilitate connectivity, avoiding the need for complex lateral connection structures
Solution Approach 2:
Instead of creating complex lateral connections around the oxide layer, the patent solves the connection problem by transitioning to the vertical dimension through through-holes in the oxide layer. This dimensional change simplifies the connection structure by allowing direct vertical electrical pathways through the protective layer
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 improves the stability and performance of the flat panel detector by preventing hydrogen plasma-induced conductivity in the transistor channel region, resulting in enhanced turn-off characteristics and product reliability.
Implementation Method 1
prone to instability due to hydrogen plasma diffusion during PIN film deposition
Implementation Method 2
hydrogen plasma diffusion during PIN film deposition
Implementation Method 3
the visible light is converted into an electric signal under the action of PIN
Data Source
AI summary
The present disclosure provides a detection substrate, a method for manufacturing the same and a flat panel detector. The detection substrate includes a base substrate and at least one pixel unit, the pixel unit includes: a transistor, an oxide layer, a reading electrode, and a photoelectric conversion structure sequentially arranged in a direction away from the base substrate, the reading electrode is electrically connected with the photoelectric conversion structure, the oxide layer is positioned between the transistor and the reading electrode, the oxide layer has a first through hole therein, an orthographic projection of the oxide layer on the base substrate at least covers that of the transistor on the base substrate, the reading electrode is electrically connected with the transistor through the first through hole, orthographic projections of the first through hole and the transistor on the base substrate are not overlapped with each other.