Semiconductor Substrate Mask Layout for Crack-Free Crystal Growth
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Solution Overview
Problem
Existing crystal growth methods face challenges in achieving high-quality semiconductor layers with differing lattice constants, often resulting in cracks and crystal defects due to substrate limitations and mask pattern designs that can lead to increased costs and reduced device performance.
Innovation Solution
A crystal growth method involving a substrate with a mask pattern of inclined strip bodies, where the width between side faces decreases with distance from the surface, allowing for vapor-phase growth of nitride semiconductor layers like AlGaN, which reduces crack formation and improves layer quality without additional processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional mask pattern is used for crystal growth, then the growth process can be completed, but cracks and crystal defects occur in the semiconductor layer
Solution Approach 1:
The mask pattern is divided into multiple strip bodies arranged in parallel, creating segmented growth regions. This segmentation prevents stress concentration that would otherwise cause cracks across the entire layer, while maintaining controlled crystal growth in each segment.
Solution Approach 2:
The strip bodies are designed with asymmetric cross-sections having inclined side faces rather than symmetric rectangular shapes. This asymmetry creates gradual stress distribution and prevents abrupt stress concentration at mask edges, eliminating crack formation during crystal growth.
2Manufacturing precision
If additional processing steps are added to improve layer quality, then crystal defects are reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The mask pattern with inclined side faces is designed in advance to preemptively prevent crack and defect formation during crystal growth. This preliminary structural design eliminates the need for subsequent defect correction steps, reducing overall manufacturing complexity.
Solution Approach 2:
The inclined side faces of the mask strips, which could be seen as adding geometric complexity, actually convert potential stress concentration points (harm) into stress-distributing features (benefit), preventing cracks without requiring additional processing steps.
3Ease of manufacture
If the mask strip width is uniform, then manufacturing is simpler, but stress concentration causes cracks in the grown layer
Solution Approach 1:
The mask strips employ asymmetric cross-sections with inclined side faces instead of uniform rectangular shapes. This asymmetric design distributes stress gradually during crystal growth, preventing crack formation while maintaining ease of manufacture through standard patterning techniques.
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 enhances the quality of crystal growth-derived layers by minimizing cracks and defects, improving the semiconductor layer's integrity and reducing the need for extra processing, thereby enhancing the performance and cost-effectiveness of semiconductor devices.
Implementation Method 1
forming, on a plurality of growth regions constituted by the exposed part of the surface layer, a crystal growth-derived layer by causing a semiconductor crystal which differs in lattice constant from the substrate to grow by a vapor-phase growth process
Data Source
AI summary
A crystal growth method of the present disclosure includes: preparing a crystal growth-derived-layer forming substrate including (a) a substrate having a surface layer, (b) a mask pattern which is formed on the surface layer and which includes a plurality of strip bodies, and (c) a plurality of crystal growth-derived layers which are formed between and on the plurality of stripe bodies so as to have gaps therebetween above the plurality of strip bodies and which differ in lattice constant from the substrate having the surface layer; and growing semiconductor layers on the plurality of crystal growth-derived layers. The semiconductor layers are respectively grown on the plurality of crystal growth-derived layers formed so as to be separated from each other, and semiconductor layers on two adjacent ones of the plurality of crystal growth-derived layers are separated from each other.