TFT Array Substrate Composite Protective Layer
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Solution Overview
Problem
The stability of thin film transistor (TFT) array substrates is compromised due to de-oxygenation of metal oxide semiconductor layers caused by insulating layers, and the low etching rate of dry etching processes using Al2O3 or SiOx layers hinders large-scale production.
Innovation Solution
A TFT array substrate with a composite lamination structure in the semiconductor protective layer, comprising a metal oxide protective layer that prevents de-oxygenation and an organic insulating layer for easy etching, improving stability and etching speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SiN x is used as the etching stop layer and gate insulating layer, then the etching performance is improved, but the metal oxide semiconductor layer undergoes de-oxygenation causing unstable TFT behavior
Solution Approach 1:
The patent segments the gate insulating layer into multiple layers: a SiN x layer (for etching stop function) and an Al 2 O 3 layer (for oxygen barrier function). This segmentation allows each layer to perform its specialized function without compromising the other, resolving the contradiction between etching performance and TFT stability.
Solution Approach 2:
The Al 2 O 3 layer acts as an intermediary between the SiN x layer and the metal oxide semiconductor layer. It prevents oxygen diffusion from the SiN x layer to the semiconductor layer, thereby protecting the semiconductor layer from de-oxygenation while allowing the SiN x layer to provide its etching stop function.
2Reliability
If Al 2 O 3 or SiO x is used as the gate insulating layer, then the TFT stability is improved, but the etching rate decreases hindering large-scale production
Solution Approach 1:
The gate insulating structure is segmented into functional layers: SiN x layer dedicated to etching stop function (providing high etching rate) and Al 2 O 3 layer dedicated to oxygen barrier function (providing TFT stability). This segmentation resolves the contradiction by assigning different materials to different functions.
Solution Approach 2:
The patent employs a composite gate insulating structure combining SiN x and Al 2 O 3 materials. This composite structure integrates the advantages of both materials: SiN x provides excellent etching stop properties while Al 2 O 3 provides superior oxygen barrier properties, achieving both high etching speed and TFT stability.
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 enhances the stability of TFT devices and facilitates large-scale production by preventing de-oxygenation of the semiconductor layer and increasing the etching speed of the insulating layers.
Implementation Method 1
a protective layer formed of metal oxide and being in contact with the semiconductor layer
Implementation Method 2
an insulating layer formed of an organic insulating material, wherein the gate electrode is provided on the base substrate
Data Source
Figure 1(a)~1(c)
Figure 1(d)~1(f)
Figure 2(a)~2(c)
AI summary
An embodiment of the present invention provides a TFT array substrate comprising: a base substrate (1) and thin film transistors. The thin film transistor comprises a gate electrode (2), a semiconductor layer (5), a semiconductor protective layer, a source electrode (8) and a drain electrode (9). The semiconductor protective layer is disposed adjacent to the semiconductor layer (5) and comprises a composite lamination structure, which comprises a protective layer formed of an insulating material capable of preventing de-oxygen of the semiconductor layer (5) and an insulating layer formed of an insulating material to be etched more easily.