Aluminium Nitride Layer Deposition via Reactive Sputtering
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Solution Overview
Problem
Current methods for depositing an aluminium nitride layer on silicon substrates, such as MBE and sputtering, are time-consuming and require ultra-high vacuum conditions, limiting efficiency and scalability.
Innovation Solution
A method involving plasma soft-etching to condition the substrate, followed by sputtering an aluminium film and then an aluminium nitride layer in a nitrogen and argon atmosphere, using a cluster tool system to facilitate efficient deposition and reduce thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MBE or conventional sputtering methods are used to deposit aluminium nitride layer, then high quality layer can be formed, but the process is time-consuming and requires ultra-high vacuum conditions
Solution Approach 1:
The invention changes the vacuum pressure parameter from ultra-high vacuum (10^-12 mbar) to low vacuum (10^-3 to 10^-1 mbar), and modifies the deposition method from conventional sputtering to reactive sputtering with nitrogen plasma. This allows forming high-quality AlN layers without requiring time-consuming ultra-high vacuum conditions, thus reducing processing time while maintaining layer quality
Solution Approach 2:
The invention replaces the mechanical pumping system required for ultra-high vacuum with a plasma-based nitrogen introduction system. Instead of relying on extreme vacuum to prevent contamination, the process uses reactive sputtering in nitrogen atmosphere to directly form AlN, substituting the vacuum mechanical system with a chemical plasma process that is faster and less complex
2Manufacturing precision
If MBE process is used to deposit aluminium nitride layer, then high quality layer can be formed, but ultra-high vacuum conditions are required which increases device complexity
Solution Approach 1:
The invention changes the vacuum pressure parameter from ultra-high vacuum (10^-12 mbar) to low vacuum (10^-3 to 10^-1 mbar), dramatically simplifying the vacuum system requirements. The plasma generation system and nitrogen introduction mechanism replace the complex ultra-high vacuum pumping infrastructure, reducing device complexity while maintaining AlN layer quality through reactive sputtering
3Manufacturing precision
If repetitive alternating fluxes are used in MBE process, then aluminium nitride layer can be deposited, but the process becomes very time consuming
Solution Approach 1:
The invention uses continuous reactive sputtering where aluminium is deposited continuously from the target while nitrogen is introduced continuously to form AlN in-situ. This eliminates the repetitive stopping and starting required in MBE alternating flux methods, maintaining continuous deposition action that significantly improves productivity and deposition efficiency while forming high-quality AlN layers
Solution Approach 2:
The invention replaces the MBE molecular beam flux control mechanism with a reactive sputtering system where plasma chemistry continuously converts aluminium atoms to AlN during deposition. This substitution eliminates the need for repetitive flux alternation and enables continuous, efficient deposition, greatly improving productivity
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 high-quality aluminium nitride layers with improved efficiency and scalability, reducing processing time and the need for ultra-high vacuum conditions, while promoting epitaxial growth and minimizing amorphous silicon nitride formation.
Implementation Method 1
conditioning a surface of the substrate by etching... The conditioning the surface of the substrate comprises plasma soft-etching the surface under vacuum
Implementation Method 2
depositing an aluminium film onto the conditioned surface of the substrate by a sputtering method under an atmosphere of Argon
Implementation Method 3
depositing an epitaxial aluminium nitride layer on the aluminium film by a sputtering method under an atmosphere of Nitrogen and Argon
Implementation Method 4
depositing an epitaxial aluminium nitride layer... promoting epitaxial growth
Data Source
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AI summary
A method for depositing an aluminium nitride layer on a substrate is provided that comprises: providing a silicon substrate; placing the substrate in a vacuum chamber; conditioning a surface of the substrate by etching and providing a conditioned surface; depositing an aluminium film onto the conditioned surface of the substrate by a sputtering method under an atmosphere of argon and depositing an epitaxial aluminium nitride layer on the aluminium film by a sputtering method under an atmosphere of nitrogen and argon.