Thin Film Transistor Auxiliary Layer for Etching Protection
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Solution Overview
Problem
Thin film transistors in flat panel displays face reliability issues due to over-etching of the semiconductor layer during manufacturing, which affects the formation of the channel and proper pixel driving.
Innovation Solution
Incorporating an auxiliary layer of amorphous silicon between the channel layer and the source/drain electrodes, protected by barrier and capping layers, to prevent over-etching without requiring additional manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the semiconductor layer is over-etched during the formation of source and drain electrodes, then the etching process removes excess material, but the channel layer is damaged and the thin film transistor cannot drive the pixel properly
Solution Approach 1:
An auxiliary layer comprising amorphous silicon is formed in advance on the channel layer before the etching process. This preliminary protective layer prevents the etching solution from directly contacting and damaging the channel layer, allowing the source and drain electrodes to be etched with proper precision while protecting the underlying channel structure.
Solution Approach 2:
The auxiliary layer acts as an intermediary protective barrier between the etching solution and the channel layer. It is selectively removed after the etching process completes, having served its protective function. This intermediary layer enables precise etching of the source and drain electrodes without compromising the integrity of the channel layer.
2Reliability
If a separate etching prevention layer is added to protect the channel layer, then the channel is protected from over-etching, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The auxiliary layer is merged with the semiconductor layer formation process. Both the channel layer and the auxiliary layer are formed in the same semiconductor deposition process, eliminating the need for a separate protective layer deposition step. This integration maintains reliability while reducing manufacturing complexity and costs.
Solution Approach 2:
The auxiliary layer serves multiple functions: it protects the channel layer during etching, provides a planar surface for subsequent electrode formation, and can be selectively removed after serving its protective purpose. This multi-functionality reduces the need for additional separate process steps.
Data Source
AI summary
A thin film transistor includes a gate electrode, a semiconductor layer, a source electrode, and a drain electrode. The semiconductor layer overlaps the gate electrode and includes a channel layer comprising an oxide semiconductor and an auxiliary layer comprising amorphous silicon. The source electrode and the drain electrode are separated from each other and connected to the semiconductor layer. A thin film transistor array panel and method of manufacturing same also is disclosed.