β-Ga2O3 Layered Crystal Growth with Stable LPE Melt Composition
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Solution Overview
Problem
Existing methods for producing β-Ga2O3 multilayer bodies face challenges such as low crystal quality, slow growth rates, and high costs due to solvent volatility and incompatible crystal structures, making them unsuitable for high-performance power devices.
Innovation Solution
A method involving liquid phase epitaxy (LPE) using a combination of Ga2O3, PbO or PbF2 as solvents, and Bi2O3, B2O3, or V2O5 to grow β-Ga2O3 single crystals on a β-Ga2O3 substrate, controlling solvent composition and temperature to achieve high crystallinity and fast growth rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vapor-phase growth methods (HVPE, MOCVD, MBE) are used to grow β-Ga2O3 epitaxial layers, then the crystal structure compatibility is improved, but the growth rate remains slow (2.7-6.0 μm/hr) and crystal quality is poor
Solution Approach 1:
The invention changes the fundamental growth parameter from vapor-phase to liquid-phase epitaxy, utilizing a molten salt solvent system (e.g., PbO-B2O3, PbF2-B2O3) to enable faster atomic transport and deposition while maintaining crystal quality through controlled cooling rates and solvent composition optimization
Solution Approach 2:
The invention introduces a molten salt solvent as an intermediary medium between the gas phase and solid crystal, where the solvent facilitates atom-by-atom deposition on the crystal surface, enabling both high growth rates and excellent crystal quality by mediating the transformation process
2Stability of the object's composition
If traditional LPE method uses PbO or PbF2 as solvent alone, then the melting point is high (making stable melt difficult), but the solvent volatility causes compositional variation and furnace material consumption
Solution Approach 1:
The invention creates a composite solvent system by combining PbO or PbF2 with B2O3 or V2O5, forming a eutectic mixture that lowers the melting point while reducing volatility. This composite solvent maintains stable composition during growth by balancing the complementary properties of each component
Solution Approach 2:
The invention changes the physical parameters of the solvent system by selecting specific compositional ratios (e.g., PbO:B2O3 = 60:40 or PbF2:B2O3 = 70:30) that optimize both melting point and volatility characteristics, enabling stable growth at lower temperatures with minimal evaporation
3Ease of manufacture
If sapphire substrate is used for β-Ga2O3 growth, then the substrate availability is improved, but the crystal structure mismatch creates multiple rotational domains and poor crystallinity
Solution Approach 1:
The invention applies local quality by using β-Ga2O3 substrate specifically in the region where high crystallinity is required, while allowing the solvent system to provide the necessary chemical environment for single-domain growth, thus combining substrate availability with crystal quality
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
Stable crystal growth with suppressed solvent evaporation allows for low-cost production of high-quality β-Ga2O3 multilayer bodies suitable for power devices and optical materials, with improved crystallinity and growth rates up to 50 µm/hr.
Implementation Method 1
allowing a β-Ga2O3 substrate to directly come into contact with the resulting melt, so that β-Ga2O3 single crystals are allowed to grow on the β-Ga2O3 substrate according to liquid phase epitaxy
Implementation Method 2
β-Ga2O3 single crystals are allowed to grow on the β-Ga2O3 substrate
Implementation Method 3
mixing (1) Ga2O3 as a solute, with (2) a combination of either PbO or PbF2 as a solvent and any one selected from the group consisting of Bi2O3, B2O3, and V2O5, as a solvent, and melting the mixture
Data Source
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AI summary
According to the present invention, there can be provided a method for producing a β-Ga2O3/β-Ga2O3 multilayer body, the method being characterized in that it comprises: mixing (1) Ga2O3 as a solute, with (2) a combination of either PbO or PbF2 as a solvent and any one selected from the group consisting of Bi2O3, B2O3, and V2O5, as a solvent (provided that a combination of PbO and Bi2O3 is excluded), and melting the mixture; and then allowing a β-Ga2O3 substrate to directly come into contact with the resulting melt, so that β-Ga2O3 single crystals are allowed to grow on the β-Ga2O3 substrate according to liquid phase epitaxy.