TiSiOx Coating Refractive Index Control via Ceramic Target Composition
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Solution Overview
Problem
Existing techniques face challenges in consistently achieving a refractive index between 1.6 to 1.9 for sputter-deposited layers, which is crucial for low-E, transparent conductive, and antireflective coatings, due to limitations in adjusting oxygen/nitrogen stoichiometry using Si or Al targets.
Innovation Solution
The use of a ceramic target with varying Ti and Si ratios allows for the deposition of Ti1-xSixOy layers, enabling consistent achievement of desired refractive indices by adjusting the Ti/Si ratio, rather than relying solely on gas flow adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Si or Al targets are used to sputter-deposit layers, then the base material can be deposited, but it is difficult to consistently achieve desired refractive indices due to limitations in adjusting oxygen/nitrogen stoichiometry
Solution Approach 1:
The patent changes the compositional parameters of the sputtering target itself, using ceramic targets with specific Ti-Si-O stoichiometries (e.g., TiSiO3, TiSi2O5, TiSiO4) rather than pure Si or Al targets. This allows direct control of the deposited layer's refractive index through target composition selection, bypassing the limitations of gas flow ratio adjustments.
Solution Approach 2:
The invention uses composite ceramic target materials containing multiple elements (Ti, Si, O) in specific ratios to achieve desired optical properties. These composite targets combine the advantages of different materials to produce layers with refractive indices between 1.6 to 1.9 that cannot be achieved with single-element targets.
2Ease of operation
If gas flow ratios are adjusted to control oxygen/nitrogen stoichiometry, then some compositional control is possible, but consistent refractive index achievement remains difficult
Solution Approach 1:
The desired compositional ratio is pre-established in the ceramic target material during manufacturing. This preliminary action ensures that the target inherently provides the correct stoichiometry for the desired refractive index, eliminating the need for complex real-time gas flow adjustments and improving consistency.
Solution Approach 2:
The patent employs monitoring of sputtering parameters and layer properties with adjustments to gas flows and power to maintain consistent refractive indices. This feedback mechanism compensates for variations in target consumption and processing conditions.
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 enables the formation of sputter-deposited layers with tunable refractive indices within the desired range, improving the consistency and repeatability of low-E and antireflective coatings, while also enhancing sputtering rates and adhesion properties.
Implementation Method 1
Sputtering is known in the art as a technique for depositing onto substrates. The layer may be deposited by a sputtering target comprising SiTiOx, and may be sputtered in an atmosphere of or including one or more of Ar, O2 and/or N2 gas(es)
Data Source
AI summary
Certain example embodiments relate to a layer of or including Ti1-xSixOy and/or a method of making the same. In certain example embodiments, the Ti1-xSixOy-based layer may be substoichiometric with respect to oxygen. In certain example embodiments of this invention, the layer may include Ti1-xSixOy where x is from about 0.05 to 0.95 (more preferably from about 0.1 to 0.9, and even more preferably from about 0.2 to 0.8, and possibly from about 0.5 to 0.8) and y is from about 0.2 to 2 (more preferably from about 1 to 2, and even more preferably from about 1.5 to 2, and possibly from about 1.9 to 2). The layer may have an index of refraction of from about 1.6 to 1.9. The layer may also be used with a transparent conductive oxide in a transparent conductive coating.