Thin-Film Transistor Barrier Layers for Copper Diffusion Control
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Solution Overview
Problem
The increase in display device resolution and size leads to higher wiring resistance, causing non-uniform electric current or voltage due to voltage drops, which deteriorates image quality, and using copper for wirings can result in device characteristic degradation due to diffusion issues.
Innovation Solution
A thin-film transistor structure is developed with a substrate, gate electrode, gate insulating layer, oxide semiconductor layer, and barrier layers to prevent copper diffusion, using copper electrodes with aluminum oxide and titanium barrier layers to maintain low resistivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If copper is used for wirings to reduce resistivity, then wiring resistance decreases, but device characteristics deteriorate due to copper diffusion
Solution Approach 1:
The patent introduces an aluminum oxide layer as an intermediary barrier between the copper wiring and the semiconductor layer. This intermediate layer prevents copper atoms from diffusing into the semiconductor while maintaining electrical connectivity, thus resolving the contradiction between using copper for low resistance and preventing device degradation from copper diffusion
Solution Approach 2:
The patent creates a composite structure combining copper (for low resistivity), aluminum oxide (for diffusion barrier), and titanium (for adhesion and additional barrier properties). This multi-material composite approach allows the system to simultaneously achieve low wiring resistance and high reliability by leveraging the complementary properties of each material
2Manufacturing precision
If display device resolution and size increase, then image quality improves, but wiring resistance increases causing voltage drops
Solution Approach 1:
The patent employs a composite wiring structure with copper core and metal oxide barrier layers, achieving both low resistivity for large displays and high resolution. The copper provides excellent electrical conductivity to minimize voltage drops in extended wirings, while the barrier layers maintain device reliability
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 structure improves current-voltage characteristics by blocking copper diffusion, maintaining superior device characteristics and achieving high image quality in large display devices.
Implementation Method 1
a first barrier layer which is disposed between the oxide semiconductor layer and the first electrode
Implementation Method 2
a second barrier layer which is disposed between the first barrier layer and the first electrode
Implementation Method 3
an oxide semiconductor layer which is formed over the gate insulating layer and includes a source section and a drain section
Data Source
AI summary
A thin-film transistor includes a substrate, a gate electrode formed over the substrate, a gate insulating layer formed over the gate electrode and the substrate, an oxide semiconductor layer formed over the gate insulating layer and comprising a source section and a drain section, a first electrode formed over the substrate and electrically connected to the source section, and a second electrode formed over the substrate and electrically connected to the drain section. The thin-film transistor further includes a first barrier layer disposed between the oxide semiconductor layer and the first electrode, a second barrier layer disposed between the first barrier layer and the first electrode, and the first electrode being electrically connected to the oxide semiconductor layer via the first barrier layer and the second barrier layer.