Titanium Oxide Thin Layer Crystallization via Localized Heating
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Solution Overview
Problem
The existing magnetron process for depositing thin layers on glass substrates, such as titanium oxide, often results in amorphous or nano-crystallized layers due to low substrate temperatures, which hinder crystallization and require costly and risky heat treatments, leading to potential breakage and inefficient crystallization.
Innovation Solution
A process where a thin layer of titanium oxide is treated at temperatures above 300°C while maintaining the opposite substrate face at ≤150°C, using an energy-providing layer to absorb and transfer energy, promoting crystallization without melting the layer, and allowing for continuous industrial implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is heated to high temperatures during or after deposition to promote crystallization, then the crystallization rate and grain size of titanium oxide layers are improved, but the substrate is at risk of breakage and the process becomes more complex and costly
Solution Approach 1:
The heating process is segmented in two key ways: (1) spatial segmentation by treating only the coated surface area rather than the entire substrate, and (2) temporal segmentation by applying heat only during the deposition process rather than as a separate post-treatment step. This allows crystallization to occur in the deposited layer without subjecting the entire substrate to high temperatures that would cause breakage.
Solution Approach 2:
The substrate is preheated to a moderate temperature (e.g., 100-200°C) before deposition begins, and the exothermic oxidation reaction is initiated during deposition. This preliminary preparation allows the crystallization process to start immediately as the material is deposited, eliminating the need for separate high-temperature post-deposition heat treatment that would risk substrate breakage.
2Manufacturing precision
If conventional infrared heating is used to heat the substrate, then the thin layer can be crystallized, but the entire substrate and opposite face are heated indiscriminately, causing thermal stress and potential breakage
Solution Approach 1:
The heating is applied locally only to the area where the thin layer is being deposited on the substrate surface. The exothermic oxidation reaction occurs specifically in the deposited titanium or titanium oxide layer, generating heat only where needed for crystallization. This localized heating avoids thermal stress and breakage by not heating the entire substrate indiscriminately.
Solution Approach 2:
The deposited titanium or titanium oxide layer itself serves as the heating source through its exothermic oxidation reaction. The material being deposited provides the energy needed for its own crystallization, eliminating the need for external heating devices that would heat the entire substrate. The layer essentially heats itself during the deposition process.
3Productivity
If the substrate running speed is increased to maintain economic efficiency, then production productivity is improved, but the substrate temperature remains too low for sufficient crystal growth
Solution Approach 1:
The exothermic oxidation reaction continues continuously throughout the deposition process, providing sustained heat generation as the thin layer is formed. This continuous internal heating ensures that crystal growth occurs throughout the entire deposition process, even at high substrate running speeds, eliminating the need to slow down production to achieve adequate crystallization.
Solution Approach 2:
The process changes the temperature parameter dynamically during deposition by utilizing the exothermic oxidation reaction. As the titanium or titanium oxide layer is deposited, the oxidation reaction generates heat that raises the local temperature in the deposited layer to levels sufficient for crystal growth, even though the substrate itself remains at a lower temperature and the deposition process continues at high speed.
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 method enhances the crystallization rate and grain size of titanium oxide layers, achieving ≥10% crystallization, maintaining substrate integrity, and enabling efficient, cost-effective production of self-cleaning coatings with improved photocatalytic activity.
Implementation Method 1
a plasma is created under a high vacuum in the vicinity of a target comprising the chemical elements to be deposited. The active species of the plasma, by bombarding the target, tear off said elements, which are deposited on the substrate
Implementation Method 2
employing a metallic titanium target or a ceramic target made of TiOx... an energy-providing layer, capable of absorbing the energy supplied during said crystallization treatment more efficiently than said at least one layer of titanium oxide and/or of creating additional energy during said crystallization treatment
Implementation Method 3
at least partial crystallization of said thin layer... increase as much as possible the rate of crystallization of these layers and the size of the crystalline grains
Data Source
AI summary
The invention relates to a method for obtaining a material including a substrate and at least one thin layer that contains an at least partially crystallised titanium oxide and is deposited on a first surface of said substrate, wherein said method comprises the following steps: depositing said at least one thin layer containing titanium oxide; subjecting said at least one thin layer containing titanium oxide to a crystallisation process by supplying a power capable of heating each point of said at least one thin layer containing titanium oxide to a temperature of at least 300°C while maintaining a temperature lower than or equal to 150°C at any point of the surface of said substrate opposite said first surface, wherein said crystallisation process is preceded by the step of depositing, on and/or under said thin layer containing titanium oxide, a power-providing layer capable of absorbing the energy supplied during said crystallisation process more efficiently than said at least one thin layer containing titanium oxide, and/or capable of generating an additional power during said crystallisation process and of transmitting at least a portion of said energy to said at least one thin layer containing titanium oxide during said crystallisation process.