SiC Crystal Growth Pedestal Cooling System
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Solution Overview
Problem
Existing manufacturing apparatuses for silicon carbide (SiC) single crystals face challenges in restricting deposition of SiC polycrystals around the pedestal, leading to reduced growth rates and potential etching of necessary growing surfaces, along with increased costs and carbon residue generation when using etching gases like HCl or hydrogen.
Innovation Solution
A manufacturing apparatus featuring a pedestal with a cooling system that includes a temperature control pipe and a coolant temperature controller, allowing for independent temperature control of the pedestal's surfaces to maintain a higher temperature around the pedestal than the seed crystal, thereby restricting SiC polycrystal deposition without the need for etching gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etching gas is introduced around the pedestal to restrict SiC polycrystal deposition, then polycrystal deposition is restricted, but the necessary growing portion on the SiC single crystal surface is etched, reducing the growth rate
Solution Approach 1:
The invention applies different temperature conditions to different spatial zones: the pedestal and surrounding area are maintained at higher temperature to prevent polycrystal deposition, while the seed crystal surface is maintained at lower temperature to promote single crystal growth. This local temperature differentiation allows simultaneous achievement of polycrystal restriction and high growth rate without etching damage
Solution Approach 2:
The invention changes the temperature parameter distribution in the growth chamber, specifically maintaining higher temperature around the pedestal and lower temperature at the crystal growth surface. This parameter change eliminates the need for etching gas while preventing polycrystal deposition and maintaining high growth rates
2Manufacturing precision
If etching gas is used to restrict SiC polycrystal deposition, then deposition is restricted, but equipment complexity and cost increase due to additional gas supply equipment
Solution Approach 1:
The invention replaces the etching gas approach with a temperature-based approach. By controlling the temperature distribution (higher around pedestal, lower at growth surface), the system achieves polycrystal restriction without requiring additional etching gas supply equipment, thereby reducing device complexity and operational costs
3Manufacturing precision
If etching gas including HCl is used, then SiC polycrystal deposition is restricted, but carbon residue is generated
Solution Approach 1:
The invention replaces chemical etching with thermal control. By maintaining higher temperature around the pedestal through controlled cooling of the pedestal body, the system prevents polycrystal deposition without using HCl etching gas, thereby eliminating carbon residue generation while achieving the same protective effect
4Manufacturing precision
If etching gas including hydrogen is used, then SiC polycrystal deposition is restricted, but the carbon-made growth chamber is etched
Solution Approach 1:
The invention replaces hydrogen etching gas with a thermal control mechanism. By controlling the temperature distribution with the pedestal cooling system, the system achieves polycrystal restriction without chemical reactions that would etch the carbon growth chamber, thereby protecting the chamber integrity
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 enables efficient restriction of SiC polycrystal deposition, maintaining a high-quality growth surface temperature and preventing clogging, thus ensuring continuous and successful growth of SiC single crystals while reducing operational costs and environmental impact.
Implementation Method 1
The temperature control pipe is disposed on a second surface side of the pedestal. The coolant temperature controller controls a temperature of a coolant that flows to the temperature control pipe.
Implementation Method 2
Therefore, a temperature around the pedestal can be higher than a temperature of a surface of the seed crystal disposed on the first surface of the pedestal.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A manufacturing apparatus for growing a SiC single crystal on a surface of a seed crystal (5) that is made of a SiC single crystal substrate by supplying a source gas (3) of SiC from a lower side of a vacuum chamber (7) toward the seed crystal (5) includes a pedestal (10), a rod member (13), and a cooling system (11). The pedestal (10) is disposed in the vacuum chamber (7). The pedestal (10) has a first surface on which the seed crystal (5) is disposed and a second surface opposed to the first surface. The rod member (13) holds the pedestal (10). The cooling system (11) includes a temperature control pipe (11a) and a coolant temperature controller (11c). The temperature control pipe (11 a) is disposed on a second surface side of the pedestal (10). The coolant temperature controller (11c) controls a temperature of a coolant that flows to the temperature control pipe (11a).