Nitride Crystal Substrate Segmentation for Large Diameter Growth
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Solution Overview
Problem
There is a need for a technique to manufacture high-quality nitride crystal substrates with larger diameters, as existing methods struggle to produce substrates exceeding 2 inches while maintaining low defect density and impurity concentration.
Innovation Solution
A nitride crystal substrate with a diameter of 100 mm or more is created by arranging small diameter seed substrates in a honeycomb pattern on a holding plate, growing a GaN film to combine them, and then slicing to obtain substrates with a continuous high dislocation density region and multiple low dislocation density regions, ensuring the surface does not include polarity inversion domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diameter of substrate for crystal growth is increased to exceed 2 inches, then the productivity and applicability of nitride crystal substrates are improved, but the manufacturing precision and quality (low defect density and impurity concentration) deteriorate
Solution Approach 1:
The substrate for crystal growth is divided into multiple small-diameter seed substrates (e.g., six 6mm diameter substrates) arranged in a honeycomb pattern. This segmentation allows each seed substrate to maintain high crystal quality while the combined structure achieves a large effective diameter (100mm or more) for high-productivity device manufacturing.
Solution Approach 2:
Multiple seed substrates are nested together on a holding plate to form a larger effective substrate area. The seed substrates are positioned and fixed on the holding plate, then covered with a single large-diameter GaN film that integrates them into one functional substrate unit with diameter exceeding 100mm.
2Productivity
If a single large-diameter substrate for crystal growth is used, then the productivity is improved, but the manufacturing precision (uniformity of crystal quality) deteriorates
Solution Approach 1:
The large substrate area is segmented into multiple small seed substrates, each maintaining uniform crystal quality independently. The segmentation prevents the quality degradation that would occur in a single large substrate while achieving the same effective area for high-productivity manufacturing.
3Productivity
If small diameter seed substrates are arranged in a honeycomb pattern and combined, then the diameter of the resulting substrate is increased to 100mm or more, but the device complexity increases
Solution Approach 1:
Multiple seed substrates are nested on a holding plate and integrated by a single large-diameter GaN film, creating a complex-appearing structure that functions as a simple, unified substrate. The nested arrangement achieves large diameter while the GaN film integration maintains structural simplicity.
Solution Approach 2:
Multiple seed substrates are merged by the GaN film into one functional unit. Although the physical arrangement involves multiple components, they function together as a single substrate with diameter 100mm or more, simplifying the overall device structure for manufacturing.
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 allows for the production of high-quality nitride crystal substrates with larger diameters, effectively addressing the need for larger substrates while maintaining low defect density and impurity concentration, and enabling efficient semiconductor device manufacturing.
Implementation Method 1
growing a GaN film to combine them
Data Source
AI summary
There is provided a nitride crystal substrate made of a nitride crystal with a diameter of 100 mm or more, having on its main surface: a continuous high dislocation density region and a plurality of low dislocation density regions divided by the high dislocation density region, with the main surface not including a polarity inversion domain.