High-Purity SiC Vapor Deposition for Contamination-Free Crystal Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods fail to provide high-purity silicon carbide materials suitable for semiconductor-grade applications due to contamination and high production costs, limiting the availability of high-purity SiC for crystal growth and vapor deposition processes.
Innovation Solution
The development of ultra-pure SiC and SiOC materials with purities of 6-nines, 7-nines, and greater, produced through polymer-derived ceramic processes, enabling efficient vapor deposition techniques for crystal growth and enhanced control over the deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (carbothermal reduction of silica, Acheson process, CVD) are used to produce silicon carbide, then production can be achieved, but the material is contaminated with boron, nitrogen, aluminum, and other metals making it unsuitable for semiconductor-grade applications
Solution Approach 1:
The invention changes the fundamental parameters of the starting materials and process conditions. Instead of using conventional silica and carbon sources that introduce contaminants, the invention employs ultra-high purity silicon and carbon precursors with controlled stoichiometry, processed through polymer-derived ceramic routes and vapor deposition techniques. This parameter change in material composition and processing conditions achieves semiconductor-grade purity while eliminating the harmful contamination inherent in conventional methods
Solution Approach 2:
The invention utilizes inert atmosphere processing throughout the synthesis route, from the polymerization stage through pyrolysis and vapor deposition. By maintaining inert conditions (typically in nitrogen or argon atmospheres), the process prevents introduction of atmospheric contaminants and minimizes unwanted chemical reactions, thereby achieving the ultra-high purity required for semiconductor applications while eliminating contamination from air exposure
2Manufacturing precision
If conventional SiC production methods are used, then material can be produced, but production costs are excessively high for commercial utilization
Solution Approach 1:
The invention segments the production process into distinct, optimized stages: precursor synthesis, polymerization, curing, pyrolysis, and vapor deposition. Each stage is independently controlled and optimized to maximize yield and minimize waste. This segmentation allows for better process control and resource utilization, reducing overall production costs while maintaining ultra-high purity standards that would be difficult to achieve in a single-step conventional process
Solution Approach 2:
The invention performs preliminary actions by pre-synthesizing ultra-high purity precursors and pre-purifying starting materials before the main production process. By preparing ultra-pure silicon and carbon precursors in advance and removing potential contaminants before polymerization and pyrolysis, the process avoids the need for expensive post-processing purification steps, thereby reducing overall production costs while ensuring semiconductor-grade purity in the final product
3Productivity
If conventional SiC materials are used in vapor deposition, then crystal growth can occur, but growth speed is limited and crystal quality is compromised by impurities and micropipes
Solution Approach 1:
The invention introduces an intermediary ultra-high purity polymer-derived ceramic SiC layer between the conventional SiC substrate and the growing crystal. This intermediary layer acts as a buffer that prevents propagation of impurities and micropipes from the substrate while providing a clean interface for high-quality crystal growth. The intermediary layer enables faster growth rates by providing a defect-free template for epitaxial growth, thereby simultaneously improving both productivity and crystal quality
4Manufacturing precision
If ultra-high purity precursors are used in vapor deposition, then higher purity SiC can be achieved, but the percentage of usable starting material is reduced
Solution Approach 1:
The invention changes the stoichiometric parameters and composition of the precursor formulations to optimize material utilization. By carefully controlling the Si:C ratio and incorporating specific additives in the polymer-derived ceramic precursors, the process maximizes the conversion efficiency of starting materials into usable SiC product. This parameter optimization ensures that ultra-high purity materials are used efficiently with minimal waste, achieving both high purity output and improved material utilization economics
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
These materials facilitate faster crystal growth, larger and purer seed crystals, and higher material utilization, resulting in high-quality semiconductor-grade silicon carbide products with improved efficiency and reduced costs.
Implementation Method 1
high purity polymer derived ceramic SiC...made by the vapor deposition of a high purity polymer derived ceramic SiC
Implementation Method 2
the use of ultra-pure precursor formulations that are cured and pyrolyzed to achieve SiC with purities of at least 99.9999%
Data Source
AI summary
Organosilicon chemistry, polymer derived ceramic materials, and methods. Such materials and methods for making polysilocarb (SiOC) and Silicon Carbide (SIC) materials having 3-nines, 4-nines, 6-nines and greater purity. Vapor deposition processes and articles formed by those processes utilizing such high purity SiOC and SiC.