Oxide TFT Ion Injection Stopper Layer Aperture Ratio
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Solution Overview
Problem
Conventional oxide TFTs in array substrates for display panels have a large size, leading to a low aperture ratio due to the need for an additional mask process and potential channel damage during etching, which affects the yield and reliability of display panels.
Innovation Solution
The introduction of an ion injection stopper layer corresponding to at least part of the channel part in the active layer of the array substrate reduces the effective channel length of oxide TFTs, allowing for a reduction in TFT size without altering the width-length ratio, thereby increasing the aperture ratio and improving stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an additional mask process is performed to manufacture an etch stopper layer, then the etching process can be controlled, but the manufacturing cost increases and the TFT size becomes larger
Solution Approach 1:
The patent extracts the etch stopper layer from the manufacturing process by using the substrate's own surface (or a naturally formed surface layer) as the etch stop reference. This eliminates the need for an additional mask process and separate etch stopper layer deposition, thereby reducing manufacturing process complexity while maintaining etching control precision.
Solution Approach 2:
The substrate surface serves multiple functions: it acts as both the base layer and the etch stop reference surface. This multi-functionality eliminates the need for dedicated etch stopper layers and mask processes, reducing both device complexity and manufacturing steps while maintaining precise etching control.
2Length of moving object
If the channel length of oxide TFTs is reduced, then the TFT size is reduced and aperture ratio is improved, but the channel becomes more susceptible to ion injection damage
Solution Approach 1:
The patent applies preliminary protective action by forming a protective layer on the substrate surface before the ion injection process. This protective layer prevents ion injection damage to the channel region, allowing the channel length to be reduced without compromising channel stability or reliability.
Solution Approach 2:
The patent addresses the channel protection issue by moving from a one-dimensional channel length reduction approach to a two-dimensional solution: reducing channel length in the planar dimension while adding vertical dimension protection through the protective layer. This allows short channels to maintain stability without requiring longer lengths.
3Area of stationary object
If the TFT size is reduced to increase aperture ratio, then more display area is available, but the manufacturing precision and device stability deteriorate
Solution Approach 1:
The patent applies local quality enhancement by providing targeted protection and control in critical regions. The protective layer is selectively positioned to protect the channel region during ion injection, while the etch stop reference ensures precise etching control in the pattern formation area. This localized quality control allows TFT size reduction without sacrificing manufacturing precision.
4Area of stationary object
If the TFT size is reduced to increase aperture ratio, then the display area increases, but the device stability and yield rate deteriorate
Solution Approach 1:
The patent applies beforehand cushioning by forming a protective layer prior to the ion injection process. This protective layer acts as a cushion that absorbs or deflects ion injection damage, preventing channel degradation even in reduced-size TFTs. This prior protection ensures device stability and maintains high yield rates despite the smaller TFT dimensions.
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 solution effectively reduces the size of oxide TFTs, enhancing the aperture ratio of display panels and improving the stability and reliability of the TFTs by preventing ion injection into the channel part.
Implementation Method 1
an ion injection stopper layer disposed on a side of the active layer away from the substrate; wherein the active layer comprises a channel part, and the ion injection stopper layer corresponds to at least part of the channel part
Data Source
AI summary
An array substrate and a display panel are disclosed. The display panel includes the array substrate. An ion injection stopper layer and an active layer of the array substrate correspond to at least part of the channel part. The ion injection stopper layer blocks ions from being injected into the channel part. Therefore, an effective channel length of oxide TFTs is reduced. A width of a channel of the oxide TFTs can be reduced without changing a width-length ratio of the oxide TFTs. As such, a size of the oxide TFTs can be reduced, and an aperture ratio of the display panel is increased.