AlN Substrate Iterative Growth for Crystal Quality Stability
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Solution Overview
Problem
The production of thick aluminum nitride single crystal layers with stable crystal qualities is challenging due to variance in quality caused by impurities, foreign substances, and crystal defects introduced during the growth process, particularly when using recycled aluminum nitride single crystal substrates as base substrates.
Innovation Solution
A method involving the iterative use of aluminum nitride single crystal substrates, where a thick aluminum nitride single crystal layer is grown, cut, and polished to create a new base substrate, allowing for repeated growth of high-quality aluminum nitride single crystal layers by controlling the thickness and quality of the base substrate, and using specific crystal faces and polishing techniques to maintain substrate integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a thick aluminum nitride single crystal layer is grown over a base substrate and then separated to be used as a new base substrate, then the substrate diameter can be increased, but the crystal quality variance increases due to impurities, foreign substances, and defects introduced during growth
Solution Approach 1:
The patent applies preliminary action by carefully controlling the growth conditions and thickness of the aluminum nitride layer before separation. By optimizing the initial growth parameters and limiting the layer thickness to prevent excessive defect accumulation, the method ensures that recycled substrates maintain acceptable crystal quality for subsequent growth cycles
Solution Approach 2:
The patent employs parameter changes by adjusting growth conditions (temperature, pressure, gas flow rates) and analyzing how these parameters affect crystal quality in recycled substrates. By optimizing these parameters, the method compensates for quality degradation and maintains stable crystal growth over multiple recycling cycles
2Productivity
If aluminum nitride single crystal layers are grown iteratively over separated substrates, then production efficiency increases, but the variance in crystal quality increases
Solution Approach 1:
The patent implements feedback mechanisms by systematically analyzing the crystal quality of substrates after each growth cycle and adjusting subsequent growth parameters accordingly. This feedback loop allows the identification and correction of quality degradation trends, maintaining consistent crystal quality across multiple iterative production cycles
Solution Approach 2:
The patent applies discarding and recovering by establishing criteria for when recycled substrates should be discarded versus continued use. By monitoring quality metrics and discarding substrates that exceed defect thresholds, the method maintains high production efficiency while preventing quality variance from compromising product reliability
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 production of aluminum nitride single crystal substrates with stable crystal qualities by reducing variance and maintaining substrate quality through iterative processing, enhancing the reliability of the substrate for electronic and light-emitting devices.
Implementation Method 1
supplying an aluminum source and a nitrogen source onto a base substrate, to grow an aluminum nitride single crystal layer over the base substrate
Implementation Method 2
cutting the aluminum nitride single crystal layer, to separate the base substrate and the aluminum nitride single crystal layer
Implementation Method 3
processing this obtained aluminum nitride single crystal layer by e.g., polishing, to produce an aluminum nitride single crystal substrate having desired surface properties
Data Source
AI summary
A method for producing an AlN single crystal substrate, the method including: i) preparing a first base substrate consisting of a first AlN single crystal; ii) growing a first AlN single crystal layer over a main face of the first base substrate, to obtain a layered body; iii) cutting the first MN single crystal layer of the layered body, to separate the layered body into a second base substrate and a first part of the first AlN single crystal layer, the second base substrate including the first base substrate and a thin film layered thereon, the thin film being a second part of the first AlN single crystal layer; iv) polishing a surface of the thin film, to obtain a third base substrate consisting of a second AlN single crystal; and v) growing a second AlN single crystal layer over the polished surface of the third base substrate.