Amorphous ITO Electrode Rapid Crystallization on Film Substrates
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Solution Overview
Problem
The existing methods for producing substrates with transparent electrodes on film substrates face challenges in reducing the time required for crystallization of ITO films at low temperatures, which hinders productivity and results in insufficient resistance reduction due to high tin oxide content, and require excessive evacuation or high-temperature annealing, increasing costs and complexity.
Innovation Solution
An amorphous transparent electrode layer with a tin oxide content of 6.5% to 16% by mass is formed on a transparent film substrate using a sputtering method with a high tin oxide content target, applying a bias voltage to create continuous regions with low resistance grains, allowing for rapid crystallization at 150°C within 30 minutes, reducing activation energy, and maintaining low resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tin oxide content of ITO is increased to reduce resistance, then the resistance decreases, but the crystallization time increases and productivity is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the tin oxide content to a specific range (5-15 mass%) rather than simply increasing it maximally. This controlled parameter adjustment achieves the balance between reducing resistance and maintaining acceptable crystallization time, resolving the contradiction between electrical performance and productivity.
Solution Approach 2:
The patent employs preliminary action by performing pre-sputtering treatment before the main ITO film formation. This preliminary step prepares the substrate surface and initiates nucleation sites that accelerate subsequent crystallization, thereby reducing the overall crystallization time while maintaining low resistance through the optimized tin oxide content.
2Productivity
If high-temperature annealing is used to reduce crystallization time, then the crystallization time decreases, but the film substrate cannot withstand the temperature
Solution Approach 1:
The patent changes the material composition parameter by incorporating specific elements (In, Sn, Ga, Zn, Al, Ti, Nb, Ta, Mo, W, Hf, or Zr) in controlled amounts to modify the crystallization behavior of ITO. This compositional modification enables crystallization at lower temperatures (100-200°C) while maintaining short crystallization times, thus resolving the contradiction between productivity and temperature constraints.
Solution Approach 2:
The patent uses composite materials by combining ITO with other metal oxides (In-Ga-Zn-O, In-Sn-Ga-Zn-O, In-Sn-Al-Ga-Zn-O, In-Sn-Ti-Ga-Zn-O, In-Sn-Nb-Ga-Zn-O, In-Sn-Ta-Ga-Zn-O, In-Sn-Mo-Ga-Zn-O, In-Sn-W-Ga-Zn-O, In-Sn-Hf-Ga-Zn-O, or In-Sn-Zr-Ga-Zn-O). This composite approach lowers the crystallization temperature while maintaining fast crystallization kinetics, effectively resolving the temperature-productivity contradiction.
3Productivity
If extensive evacuation is performed to reduce water partial pressure, then the crystallization time decreases, but the evacuation time increases and productivity is reduced
Solution Approach 1:
The patent changes the material composition by incorporating specific metal oxides that catalyze crystallization or reduce the activation energy barrier. This compositional parameter change enables rapid crystallization even under moderate vacuum conditions, eliminating the need for extensive evacuation to achieve low water partial pressure, thus resolving the contradiction between crystallization speed and evacuation time.
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 approach enables the production of substrates with low-resistance transparent electrodes in a shorter time, improving productivity by reducing crystallization time and avoiding the need for extensive evacuation or high-temperature processing, while maintaining low resistivity and high transmittance.
Implementation Method 1
a method in which an amorphous ITO film is formed on a film substrate by a sputtering method
Implementation Method 2
heated/annealed under an oxygen atmosphere to transform the amorphous ITO film into a crystalline ITO film
Implementation Method 3
transform the amorphous ITO film into a crystalline ITO film
Implementation Method 4
when a bias voltage of 0.1 V is applied to the amorphous transparent electrode layer, the amorphous transparent electrode layer has continuous regions where a current value at a voltage-applied surface is 50 nA or more
Data Source
AI summary
A substrate with a transparent electrode which includes an amorphous transparent electrode layer on a transparent film substrate. When a bias voltage of 0.1 V is applied to the amorphous transparent electrode layer, the layer has continuous regions where a current value at a voltage-applied surface is 50 nA or more. Each of the continuous regions has an area of 100 nm2 or more and the number of the continuous regions is 50/μm2 or more. In one embodiment, the layer has a tin oxide content of 6.5% or more and 8% or less by mass. With respect to the substrate with a transparent electrode according to the present invention, the transparent electrode layer may be crystallized in a short period of time.