Silicon-Based Molten Composition for SiC Crystal Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for growing silicon carbide single crystals, such as the sublimation and chemical vapor deposition methods, face limitations including high production costs, defects like micropipes, and temperature constraints, which hinder the production of high-quality silicon carbide single crystals suitable for advanced electrical power semiconductor devices.
Innovation Solution
A silicon-based molten composition comprising silicon (Si), yttrium (Y), and iron (Fe) is used in a solution growing method, with specific ratios to control impurity precipitation and maintain a stable crystal growth process, allowing for the growth of high-quality silicon carbide single crystals at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sublimation method is used to grow silicon carbide single crystal at high temperature (≥2000°C), then the single crystal can be grown, but defects such as micropipes or stacking errors are generated
Solution Approach 1:
The patent changes the temperature parameter from high temperature (≥2000°C sublimation) to lower temperature (1700-2000°C solution growing), and changes the chemical environment from pure sublimation to molten composition with specific ratios of Si, Y, and Fe, thereby reducing defects while maintaining crystal growth
Solution Approach 2:
The patent uses a composite molten composition consisting of silicon (Si), yttrium (Y), and iron (Fe) in specific ratios instead of pure silicon carbide sublimation, creating a eutectic system that enables lower temperature growth with fewer defects
2Manufacturing precision
If the chemical vapor deposition method is used, then thin membrane level growth is achieved, but thickness is limited
Solution Approach 1:
The patent changes the growth method from chemical vapor deposition to solution growing from molten composition, enabling transition from thin membrane level to bulk crystal level by utilizing the liquid phase mass transport and higher solubility at elevated temperatures
3Productivity
If yttrium is added to increase carbon solubility, then crystal growth is enhanced, but yttrium silicide precipitation occurs as impurity
Solution Approach 1:
The patent optimizes the concentration parameter of yttrium in the molten composition and introduces iron as a controlling element, maintaining yttrium content within specific ranges (0.1-5 wt%) to enhance carbon solubility while preventing excessive yttrium silicide precipitation through compositional balance
Solution Approach 2:
The patent uses iron as an intermediary element that interacts with yttrium in the molten composition, suppressing the harmful precipitation of yttrium silicide while allowing yttrium to fulfill its beneficial role in increasing carbon solubility and enhancing crystal growth
4Temperature
If conventional solution growing method is used, then lower temperature growth is achieved, but impurity precipitation and unstable process occur
Solution Approach 1:
The patent employs a composite molten composition with silicon, yttrium, and iron in specific ratios that creates a eutectic system with lower melting point and improved stability, enabling sustained crystal growth at lower temperatures without the composition instability and impurity precipitation problems of conventional methods
Solution Approach 2:
The patent optimizes multiple parameters including temperature (1700-2000°C), composition ratios (Si:Y:Fe), and holding time to achieve a stable growth window where the molten composition maintains its properties without premature solidification or impurity precipitation
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
The silicon-based molten composition enhances carbon solubility, suppresses yttrium silicide precipitation, and enables continuous single crystal growth, resulting in high-quality silicon carbide crystals with increased growth speed and purity, suitable for advanced semiconductor applications.
Implementation Method 1
The silicon-based molten composition enhances carbon solubility
Implementation Method 2
suppresses yttrium silicide precipitation
Implementation Method 3
obtaining a silicon carbide single crystal on the silicon carbide seed crystal from the molten solution
Data Source
AI summary
A silicon-based molten composition according to an exemplary embodiment is used in a solution growing method for forming a silicon carbide single crystal, includes silicon (Si), yttrium (Y), and iron (Fe), and is expressed in Formula 1.SiaYbFec [Formula 1]In Formula 1, the a is equal to or greater than 0.4 and equal to or less than 0.8,the b is equal to or greater than 0.2 and equal to or less than 0.3, and the c is equal to or greater than 0.1 and equal to or less than 0.2.