Silicon Carbide Single Crystal Growth via Solution Process
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The sublimation process for growing silicon carbide single crystals is limited by high temperatures, which lead to faults like micropipes and stacking faults, and has low economic efficiency due to slow crystal growth speed, while other methods like chemical vapor deposition struggle with high purity and limited thickness.
Innovation Solution
A solution growth process using a Si—C alloy solution with additive metals, where silicon feedstock is periodically fed into the alloy solution to maintain the molar ratio and prevent growth slowdowns, utilizing a device with a separate silicon feed unit to manage the feedstock introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sublimation process is used to grow silicon carbide single crystal at high temperature, then the crystal can be grown, but various faults such as micropipe and stacking faults are generated and production costs increase
Solution Approach 1:
The invention changes the temperature parameter from high temperature (2200°C or more in sublimation process) to moderate temperature (1600-1900°C in solution growth process), and changes the phase state from vapor phase to liquid phase, thereby reducing production costs while maintaining crystal quality by avoiding fault generation
Solution Approach 2:
The invention transitions from the sublimation process (solid-vapor phase transition) to the solution growth process (liquid-solid phase transition), using a Si-C alloy solution as the growth medium to grow silicon carbide single crystal at lower temperatures without generating micropipe or stacking faults
2Reliability
If the Czochralski process is used to grow silicon carbide single crystal, then crystal quality is maintained, but crystal growth speed is very low (50 μm/hr or less)
Solution Approach 1:
The invention optimizes the composition parameters of the Si-C alloy solution by adding specific metals (Al, Ti, Cr, Fe, Co, Dy, or La) to change the physical and chemical properties of the growth medium, thereby significantly increasing crystal growth speed to 100-500 μm/hr while maintaining crystal quality through controlled solution chemistry
Solution Approach 2:
The invention uses a composite Si-C alloy solution containing silicon, carbon, and additive metals as the growth medium, where the combination of multiple elements creates optimal conditions for both high growth speed and high crystal quality, overcoming the limitations of pure silicon or simple carbon-silicon mixtures
3Device complexity
If silicon feedstock is not supplemented during solution growth, then the process is simple, but the molar ratio of Si to additive metal decreases and crystal growth stops
Solution Approach 1:
The invention implements a feedback control mechanism where the molar ratio of Si to additive metal is monitored during the solution growth process, and silicon feedstock is automatically supplemented when the ratio falls below a predetermined level, ensuring continuous crystal growth without interruption while maintaining process simplicity through automated control
Solution Approach 2:
The system performs self-service by automatically detecting when silicon supplementation is needed through molar ratio monitoring and autonomously adding the required amount of silicon feedstock, eliminating the need for complex manual intervention while ensuring continuous crystal growth
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 increases crystal growth speed, prevents unintended growth stops, and enhances the homogeneity and purity of silicon carbide single crystals, improving economic efficiency and reducing fault occurrence.
Implementation Method 1
A liquid phase growth process using a Czochralski process is used to grow a silicon carbide single crystal
Implementation Method 2
increasing the temperature to about 1600 to 1900° C., and coming the silicon carbide seed disposed at an upper side of the crucible into contact with molten liquid
Implementation Method 3
a sublimation process for sublimating silicon carbide as a raw material at a high temperature of 2000° C. or more to grow the single crystal
Data Source
AI summary
Provided is a method for manufacturing a silicon carbide single crystal using a solution process including coming a seed crystal substrate for growing silicon carbide into contact with a Si—C alloy solution including at least one additive metal and growing the silicon carbide single crystal on a seed crystal for growing silicon carbide, including feeding a silicon feedstock into an alloy solution when a molar ratio of Si and the additive metal is lower than an initially set value as the reaction progresses. The method increases a crystal growth speed, maintains the growth speed, and prevents the growth from unwillingly stopping when the silicon carbide single crystal is manufactured using a solution growth process.