Thin-Film Transistor Electrodes That Prevent Etch Residue
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Solution Overview
Problem
Existing thin film transistors face issues with residual films of low-reflective metals remaining after wet etching, leading to increased reflectance and potential defects due to spark-shaped residual films during dry etching.
Innovation Solution
A thin film transistor design with a multilayer structure for the source and drain electrodes, comprising a first layer of low-reflective material and a second layer of galvanic metal, where the galvanic metal has higher electron affinity than the low-reflective material, ensuring no residual film formation during etching and reducing reflectance through destructive interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a low-reflective material layer is used for the source and drain electrodes, then reflectance is reduced, but residual films remain after wet etching
Solution Approach 1:
The source and drain electrodes are divided into multiple layers: a lower electrode layer (first layer) made of low-reflective material and an upper electrode layer (second layer) made of galvanic metal. This segmentation allows each layer to serve different functions - the lower layer reduces reflectance while the upper layer enables complete etching without residual films
Solution Approach 2:
The upper electrode layer made of galvanic metal acts as an intermediary that facilitates complete etching. The galvanic metal layer enables the etching process to proceed fully through the electrode structure without leaving residual films from the low-reflective material, thus mediating between the low-reflective property and the etching completeness
2Ease of manufacture
If wet etching is performed on low-reflective metals, then the etching process can be completed, but residual films remain due to etchant limitations
Solution Approach 1:
The electrode structure uses a composite material approach by combining low-reflective material with galvanic metal in a multilayer configuration. This composite structure leverages the advantages of both materials - the low-reflective property of the first layer and the etching-friendly characteristics of the galvanic metal second layer, enabling complete etching without residual films
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 multilayer structure effectively prevents residual film formation and reduces reflectance, maintaining low resistance wiring characteristics and preventing defects, enhancing the performance of display apparatuses.
Implementation Method 1
a second layer disposed on the first layer and including a galvanic metal; and the galvanic metal has a higher electron affinity than the low-reflective material
Implementation Method 2
adjusting a multilayer film structure having low reflection characteristics of a source electrode and a drain electrode
Data Source
AI summary
A thin film transistor, a method of manufacturing the same, and a display apparatus including the same are discussed. The thin film transistor can include a base substrate, an active layer on the base substrate, a gate electrode spaced apart from the active layer and overlapping at least part of the active layer, a source electrode connected to the active layer, and a drain electrode spaced apart from the source electrode and connected to the active layer. Each of the gate electrode, the source electrode, and the drain electrode can include a first layer including a low-reflective material, a second layer disposed on the first layer and including a galvanic metal, a third layer disposed on the second layer, and a fourth layer disposed on the third layer. Further, the galvanic metal can have a higher electron affinity than the low-reflective material.