Mixed-Gas Chromium Nitride Films by Reactive Magnetron Sputtering
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Solution Overview
Problem
Existing methods for producing chromium nitride (CrN) thin films, such as molecular beam epitaxy, are cost-intensive and require very low pressures, making them challenging to implement.
Innovation Solution
A method involving reactive radio frequency magnetron sputtering of chromium in a gaseous mixture of nitrogen and argon, with ratios ranging from 1:2 to 1:10, to form CrN thin films with controlled thickness and composition, allowing for the formation of CrOxNy phases and varying crystal structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If molecular beam epitaxy is used to produce CrN thin films, then high-quality films with controlled properties are achieved, but the process becomes cost-intensive and requires very low pressures making implementation challenging
Solution Approach 1:
The patent changes the working pressure parameter from very low pressure (10^-10 Torr in MBE) to moderate pressure (10^-3 to 1 Torr in sputtering), and changes the deposition mechanism from molecular beam epitaxy to reactive magnetron sputtering. This allows achieving CrN films with controlled stoichiometry and crystal structure while simplifying the manufacturing process and reducing costs
Solution Approach 2:
The patent introduces reactive gases (nitrogen and argon) as intermediaries in the sputtering process to form CrN compounds. The nitrogen gas reacts with chromium atoms during deposition to form the desired nitride phase, while argon serves as the plasma-generating gas. This intermediary approach enables controlled film formation at moderate pressures without requiring ultra-high vacuum conditions
2Manufacturing precision
If very low pressure (10^-10 Torr) is used in molecular beam epitaxy, then high-quality CrN films are produced, but the equipment requirements and operational complexity increase significantly
Solution Approach 1:
The patent changes the pressure parameter from 10^-10 Torr to 10^-3 to 1 Torr, which dramatically reduces vacuum system complexity. The moderate pressure regime allows using standard magnetron sputtering equipment with conventional vacuum pumps instead of requiring complex ultra-high vacuum systems with multiple pumping stages and extreme pressure control
3Ease of manufacture
If reactive magnetron sputtering with nitrogen and argon mixture is used, then cost-effective CrN film production is achieved, but control over film composition and phase formation becomes more challenging
Solution Approach 1:
The patent employs feedback control by monitoring the nitrogen to argon gas flow ratio and adjusting deposition parameters accordingly. By controlling the nitrogen partial pressure through regulated gas flow rates, the process maintains optimal conditions for forming desired CrN phases (CrN, Cr2N, or CrOxNy) with controlled stoichiometry, despite operating at moderate pressures with reactive gases
Solution Approach 2:
The patent uses dynamic control of gas flow ratios during deposition to adjust film composition in real-time. By varying the nitrogen to argon ratio during the sputtering process, the method can dynamically control the nitride phase formation, stoichiometry, and crystal structure, enabling precise composition control while maintaining process simplicity
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
The method produces CrN thin films with controlled electronic phase transitions, suitable for use as temperature sensors, and can be adapted for other metal nitrides, offering a cost-effective alternative to molecular beam epitaxy.
Implementation Method 1
reactive radio frequency magnetron sputtering chromium onto a substrate
Implementation Method 2
reactive radio frequency magnetron sputtering chromium onto a substrate in the presence of a gaseous mixture comprising nitrogen and argon
Data Source
AI summary
A method for producing a chromium nitride (CrN) thin film is provided. The method includes reactive radio frequency magnetron sputtering chromium onto a substrate in the presence of a gaseous mixture including nitrogen and argon to form the CrN thin film, where a ratio of the nitrogen gas to the argon gas is 1:2 to 1:10, and where the CrN thin film has an average thickness of 500 to 1500 nm. The CrN film as prepared by the method of the present disclosure can be used in sensors for cryogenic temperature.