Diamond Substrate Defect Reduction via Patterned Growth
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Solution Overview
Problem
Current methods for manufacturing diamond substrates, particularly through heteroepitaxial growth, face challenges with high dislocation defects and thermal stress, which hinder the production of large-area, high-quality substrates suitable for practical use.
Innovation Solution
A method involving patterned diamond growth on a foundation surface, followed by removal and subsequent re-growth in pattern gaps, using chemical vapor deposition, to reduce defects and stress, allowing for homoepitaxial or heteroepitaxial growth on various substrates, including diamond and other materials like iridium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If heteroepitaxial growth is used to obtain large-area substrates, then productivity and area are improved, but dislocation defects increase due to lattice mismatch
Solution Approach 1:
The growth process is divided into multiple stages: initial heteroepitaxial growth to establish a foundation, followed by selective lateral overgrowth in patterned regions. This segmentation allows the substrate to achieve large area through tiling while maintaining low defect density in each segment through controlled growth conditions.
Solution Approach 2:
Different regions of the substrate are grown under different conditions. The patterned regions undergo selective lateral overgrowth with optimized parameters to minimize dislocations, while non-patterned regions serve as sacrificial or support areas. This local optimization ensures high quality in critical areas while maintaining overall large area coverage.
2Adaptability or versatility
If heteroepitaxial growth on different foundation materials is used, then adaptability and ease of manufacture are improved, but thermal stress increases due to thermal expansion coefficient mismatch
Solution Approach 1:
The growth parameters (temperature, pressure, gas composition) are adjusted based on the specific foundation material being used. By optimizing these parameters for each material system, the thermal stress is minimized while maintaining compatibility with diverse foundation materials such as silicon, sapphire, or metal substrates.
3Ease of manufacture
If conventional epitaxial growth is used, then manufacturing simplicity is maintained, but defect density remains high due to lattice mismatch
Solution Approach 1:
A preliminary patterning step is performed on the foundation substrate before epitaxial growth. This creates a template that guides the subsequent selective lateral overgrowth, ensuring that diamond forms in controlled regions with minimal defects. The preliminary action of patterning enables defect reduction without significantly complicating the overall manufacturing process.
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 approach significantly reduces dislocation defects and thermal stress, enabling the production of high-quality diamond substrates with minimal warpage and cracking, suitable for semiconductor applications.
Implementation Method 1
growing diamond from the patterned diamond prepared in the first step to form the diamond in a pattern gap of the patterned diamond prepared in the first step
Data Source
AI summary
A method for manufacturing a diamond substrate, including: a first step of preparing patterned diamond on a foundation surface, a second step of growing diamond from the patterned diamond prepared in the first step to form the diamond in a pattern gap of the patterned diamond prepared in the first step, a third step of removing the patterned diamond prepared in the first step to form a patterned diamond composed of the diamond formed in the second step, and a fourth step of growing diamond from the patterned diamond formed in the third step to form the diamond in a pattern gap of the patterned diamond formed in the third step. There can be provided a method for manufacturing a diamond substrate which can sufficiently suppress dislocation defects, a high-quality diamond substrate, and a freestanding diamond substrate.