Nitride Single Crystal Growth via Nitrogen Atmosphere Shielding
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Solution Overview
Problem
The growth of III group nitride single crystals is hindered by coloration due to trace oxygen and impurities, and deformation of reaction containers, which complicates mass production and affects crystal quality.
Innovation Solution
A method involving a reaction container with a specific design that includes a crucible, an outer container, and a pressure container, where a nitrogen-containing atmosphere is supplied to prevent oxygen absorption and impurity inclusion, maintaining temperature uniformity and shielding the atmosphere to prevent crucible deformation and coloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a material for absorbing oxygen such as carbon or steel wool is provided outside the crucible, then oxygen absorption is improved, but impurities are generated causing crystal coloration
Solution Approach 1:
The invention removes the oxygen-absorbing material (carbon or steel wool) from the reaction container entirely. Instead, the reaction container is designed with a specific structure including a groove at the fitting face between lid and main body, which allows nitrogen-containing atmosphere to be supplied directly to the crucible without requiring separate oxygen-absorbing materials that would generate impurities.
Solution Approach 2:
The invention introduces a nitrogen-containing atmosphere as an intermediary medium to protect the crystal growth environment. The groove structure serves as a conduit for this intermediary atmosphere, replacing the need for chemical oxygen-absorbing materials and preventing both oxidation and impurity generation.
2Manufacturing precision
If the confinement of the crucible is improved to prevent impurity inclusion, then crystal quality is improved, but the growth rate is considerably lowered
Solution Approach 1:
The invention applies local quality control by creating a nitrogen-rich atmosphere specifically at the crucible region through the groove structure, while maintaining overall system openness. This localized atmosphere control prevents impurity inclusion at the critical crystal growth interface without requiring complete system confinement, thus maintaining growth rate.
Solution Approach 2:
The invention uses partial action by supplying nitrogen-containing atmosphere only where needed (at the crucible through the groove) rather than completely confining the entire reaction container. This partial atmospheric control achieves sufficient impurity prevention while avoiding the excessive confinement that would reduce growth rate.
3Reliability
If the reaction container is sealed to prevent oxygen ingress, then oxidation is prevented, but the container deforms due to pressure
Solution Approach 1:
The invention segments the sealing function by creating a groove at the fitting face between lid and main body. This groove allows the container to remain structurally open (preventing pressure buildup and deformation) while still providing a controlled pathway for nitrogen-containing atmosphere, achieving oxidation prevention without complete sealing.
Solution Approach 2:
The invention uses an inert nitrogen-containing atmosphere to prevent oxidation instead of creating a hermetically sealed environment. The groove structure allows this inert atmosphere to be supplied continuously, preventing oxidation while the open structure prevents pressure-induced deformation.
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 coloration and deformation, enhances temperature uniformity, reduces flux evaporation, and ensures high-quality nitride single crystal growth, facilitating mass production.
Implementation Method 1
supplying an atmosphere containing nitrogen into the outer container to grow the nitride single crystal... shielding the atmosphere to prevent crucible deformation and coloration
Implementation Method 2
a heater is provided in a pressure container... generating a melt in the crucible
Implementation Method 3
flux and raw material are melted in a crucible to grow GaN signel crystal
Data Source
AI summary
Materials of a nitride single crystal of a metal belonging to III group and a flux are contained in a crucible, which is contained in a reaction container, the reaction container is contained in an outer container, the outer container is contained in a pressure container, and nitrogen-containing atmosphere is supplied into the outer container and melt is generated in the crucible to grow a nitride single crystal of a metal belonging to III group. The reaction container includes a main body containing the crucible and a lid. The main body includes a side wall having a fitting face and a groove opening at the fitting face and a bottom wall. The lid has an upper plate part including a contact face for the fitting face of the main body and a flange part extending from the upper plate part and surrounding an outer side of said side wall.