Silicon Oxide Coating via Radical Scavenger CVD
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Solution Overview
Problem
Existing processes for forming silicon oxide coatings on glass substrates are limited by inefficiency and powder formation during deposition, particularly in chemical vapor deposition (CVD) processes, which restricts deposition rates and increases costs.
Innovation Solution
A CVD process using a gaseous mixture of silane, oxygen, a radical scavenger, and phosphorus- or boron-containing compounds, such as triethylphosphite or triethylborane, is employed to form silicon oxide coatings at elevated temperatures and atmospheric pressure, achieving deposition rates of 150 nm/m/min or more on moving glass substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CVD processes are used to form silicon oxide coatings, then coating formation is achieved, but deposition rates are limited and powder formation occurs
Solution Approach 1:
The patent changes the chemical parameters of the gaseous mixture by introducing phosphorus-containing compounds (such as phosphine or trimethylphosphine) at controlled concentrations (0.01-5% by volume). This parameter modification alters the reaction kinetics and mechanism, enabling higher deposition rates while suppressing powder formation through modified surface chemistry and reduced pre-reaction of silane and oxygen
Solution Approach 2:
The phosphorus-containing compound acts as a chemical intermediary or catalyst in the CVD process. It modifies the reaction pathway between silane and oxygen, facilitating controlled decomposition and deposition. The phosphorus compound intermediates the reaction process, allowing faster deposition without the harmful pre-reaction that causes powder formation
2Productivity
If deposition rate is increased in conventional processes, then productivity improves, but powder formation increases and coating quality deteriorates
Solution Approach 1:
The patent modifies multiple parameters simultaneously: phosphorus compound concentration (0.01-5%), temperature range (200-400°C), and gas flow ratios. These parameter changes work together to enable high deposition rates (150 nm*m/min or more) while maintaining coating uniformity. The phosphorus compound specifically controls the reaction zone, preventing premature reaction and ensuring uniform deposition even at high speeds
Solution Approach 2:
The patent uses a small but significant amount of phosphorus-containing compound (0.01-5% by volume in the gaseous mixture). This partial addition is sufficient to fundamentally alter the deposition mechanism and achieve both high rate and high quality, without needing excessive amounts that would complicate the process or contaminate the coating
3Ease of manufacture
If conventional CVD processes are used, then silicon oxide coating is formed, but process efficiency is limited and costs increase
Solution Approach 1:
The patent changes the chemical environment by adding phosphorus-containing compounds, which fundamentally improves the efficiency of silicon precursor utilization. The modified reaction chemistry enables more complete and controlled decomposition of silane, reducing waste and improving deposition efficiency. This allows faster production with better material utilization
Solution Approach 2:
The phosphorus compound serves as a reaction intermediary that enhances the efficiency of silicon deposition. It facilitates more effective conversion of silicon precursor into coating material, reducing the amount of precursor needed and improving overall process efficiency. The intermediary promotes direct decomposition pathways that are more efficient than conventional thermal decomposition
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 process enhances deposition rates, reduces pre-reaction and powder formation, and allows for the formation of high-quality, uniform silicon oxide coatings with reduced silicon-containing precursor usage, leading to cost-effective and efficient coating production.
Implementation Method 1
a chemical vapor deposition (CVD) process for forming a silicon oxide coating
Implementation Method 2
The gaseous mixture is reacted over the glass substrate to form a silicon oxide coating
Data Source
AI summary
A chemical vapor deposition process for forming a silicon oxide coating includes providing a moving glass substrate. A gaseous mixture is formed and includes a silane compound, a first oxygen-containing molecule, a radical scavenger, and at least one of a phosphorus-containing compound and a boron-containing compound. The gaseous mixture is directed toward and along the glass substrate. The gaseous mixture is reacted over the glass substrate to form a silicon oxide coating on the glass substrate at a deposition rate of 150 nm*m/min or more.