Beta-Ga2O3 Crystal Growth via EFG Without Necking
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Solution Overview
Problem
The growth of β-Ga2O3 single crystals by the Bridgman method faces challenges with crucible adhesion, making it difficult to remove the crystal, and the EFG method struggles to control twinning, leading to crystal defects.
Innovation Solution
The method involves growing β-Ga2O3 single crystals using the EFG method without a necking process and controlling the width transition between the seed crystal and the grown crystal, along with rapid cooling to manage twinning, while using a crucible with sufficient heat resistance to prevent thermal shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Bridgman method is used to grow β-Ga2O3 single crystals, then the crystals can be grown without twins, but the crystals adhere strongly to the crucible and are difficult to remove
Solution Approach 1:
The patent segments the crucible into two functional zones: a lower growth zone made of Ir or Ir alloy for twin-free crystal growth, and an upper release zone made of material with low adhesion to the crystal (such as graphite, molybdenum, or tungsten). This segmentation allows the crystal to be grown in the lower zone and then easily released from the upper zone without compromising crystal quality or removal ease.
Solution Approach 2:
The patent introduces an intermediary material (the upper crucible portion made of low-adhesion material) that mediates between the high-adhesion Ir crucible and the crystal. This intermediary layer allows the crystal to be grown on the Ir surface while providing a release surface for easy removal, solving the adhesion problem without affecting crystal growth quality.
2Manufacturing precision
If the EFG method is used to grow β-Ga2O3 single crystals, then the crystals can be grown with controlled dimensions, but the twinning of crystal cannot be controlled
Solution Approach 1:
The patent changes the growth parameters by using a temperature gradient approach where the lower crucible zone is maintained at a higher temperature to promote single crystal growth without twins, while the upper zone has a lower temperature for easy release. This parameter change in temperature distribution along the crucible height enables both dimensional control and twinning prevention.
Solution Approach 2:
The patent uses a composite crucible structure combining different materials (Ir/Ir alloy in the lower zone and low-adhesion materials like graphite or molybdenum in the upper zone) to achieve both twin-free crystal growth and easy crystal removal. The composite structure leverages the advantageous properties of each material for different functional requirements.
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 effectively prevents twinning and allows for the controlled growth of β-Ga2O3 single crystals, reducing the likelihood of crystal defects and adhesion issues, resulting in high-quality crystals.
Implementation Method 1
a die (14) having a slit (14A)... drawn up by capillary action
Implementation Method 2
the crystal seed (20) in contact with the Ga2O3-based melt (12) is pulled up, thereby growing a plate-like β-Ga2O3-based single crystal (25)
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
Provided is a method for growing a β-Ga2O3 single crystal, which is capable of effectively suppressing twinning of the crystal. One embodiment of the present invention provides a method for growing a β-Ga2O3 single crystal (25) using an EFG method, which comprises: a step wherein a seed crystal (20) is brought into contact with a Ga2O3 melt (12); and a step wherein the seed crystal (20) is pulled and a β-Ga2O3 single crystal (25) is grown without performing a necking process. In the method for growing a β-Ga2O3 single crystal, the widths of the β-Ga2O3 single crystal (25) are 110% or less of the widths of the seed crystal (20) in all directions.