SiC Sublimation Crucible Insulation for Radial Temperature Control
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Solution Overview
Problem
Conventional physical vapor transport (PVT) systems for growing bulk semiconductor single crystals, such as silicon carbide, face challenges in achieving homogeneous temperature distribution, leading to inefficient use of source material and reduced crystal quality due to thermal conductivity issues and recrystallization effects.
Innovation Solution
Incorporating a thermally insulating unit within the source material compartment of the crucible to reduce radial temperature variations, combined with a heating system that generates a uniform temperature field around the crucible, enhances heat homogeneity and reduces energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional PVT systems use standard heating arrangements without internal insulation, then the system structure remains simple, but radial temperature distribution becomes inhomogeneous leading to source material waste and reduced crystal quality
Solution Approach 1:
The patent applies local quality by introducing a thermally insulating unit specifically at the radially outer region of the crucible where heat loss is greatest. This localized insulation approach targets the specific area needing temperature correction without modifying the entire crucible structure, thereby achieving homogeneous radial temperature distribution while minimizing structural complexity changes.
2Use of energy by moving object
If the crucible is heated with high power to maintain temperature, then the temperature field is sufficient for sublimation, but energy consumption increases and thermal gradients cause recrystallization in the source material
Solution Approach 1:
The patent converts the harmful effect of radial heat loss into a benefit by strategically placing the thermally insulating unit at the radially outer region. This insulation prevents heat escape, reduces the overall energy input required for maintenance heating, and eliminates thermal gradients that cause recrystallization, thereby improving both energy efficiency and temperature uniformity.
3Productivity
If the source material compartment is fully heated, then sublimation efficiency increases, but thermal conductivity issues cause temperature inhomogeneity and source material waste
Solution Approach 1:
The patent changes the thermal parameters of the source material compartment by introducing a thermally insulating unit with different thermal conductivity properties. This modification alters the heat distribution parameters, creating more uniform temperature conditions that maintain sublimation efficiency while preventing the thermal conductivity issues that lead to source material waste and recrystallization.
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 results in a more efficient use of source material, maintaining a consistent gas phase composition, and significantly increasing the length and quality of the grown single crystals, while reducing energy consumption and extending crucible lifetime.
Implementation Method 1
PVT is a crystal growing method that essentially involves sublimation of a suitable source material followed by re-condensation at a seed crystal
Implementation Method 2
The source material is sublimed by heating
Implementation Method 3
a thermally insulating unit arranged within the source material compartment at a sidewall of the crucible
Implementation Method 4
reduce radial temperature variations
Implementation Method 5
The sublimed vapor then diffuses in a controlled manner due to a temperature field having a gradient established between source material and seed crystal
Implementation Method 6
sublimation of a suitable source material followed by re-condensation at a seed crystal
Implementation Method 7
Physical vapor transport (PVT) is generally used for growing bulk SiC single crystals
Data Source
AI summary
The present invention relates to systems and methods for growing bulk semiconductor single crystals, and more specifically, for growing bulk semiconductor single crystals, such as silicon carbide, based on physical vapor transport. The sublimation system comprises a crucible (202) having a longitudinal axis (212) and a sidewall (218) extending along the longitudinal axis (212), wherein the crucible (202) comprises a fixing means for at least one seed crystal (210) and at least one source material compartment (204) for containing a source material (208); and a heating system for generating a temperature field around a circumference of the crucible (202) along the longitudinal axis (212) of the crucible (202); a thermally insulating unit (214) arranged within the source material compartment (204) at the sidewall (218) of the crucible (202).