Intersecting Nozzles for Group-III Nitride Crystal Growth
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Solution Overview
Problem
In the production of Group-III nitride semiconductor crystals, the existing vapor-phase growth methods face challenges with the precipitation of crystals into the raw material gas introduction path and poor mixing of Group-III element-containing and nitrogen element-containing gases, leading to defects and reduced growth rates.
Innovation Solution
The apparatus features a raw material reaction chamber with a raw material nozzle and a nitrogen source nozzle that intersect before the board, creating a mixing area where the gases combine, along with a rotation mechanism for the board-holding member, which enhances gas mixing and suppresses crystal precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gases are supplied in parallel from perpendicular nozzles, then the raw material introduction path is simple, but the gases are not easily mixed together resulting in poor uniformity of film thickness and crystallinity
Solution Approach 1:
The nitrogen source nozzle is configured with an asymmetric structure where the spray direction is inclined at a specific angle (e.g., 30-60 degrees) relative to the board surface, rather than being perpendicular. This asymmetric angle allows the nitrogen-containing gas to intersect with the Group-III element-containing gas flow, creating effective mixing while maintaining a relatively simple device structure.
Solution Approach 2:
The invention introduces a new spatial dimension by inclining the nitrogen source nozzle at an angle to the board surface, creating a three-dimensional gas flow pattern. The gases mix in a diagonal trajectory rather than in parallel layers, enabling thorough mixing without requiring complex multi-directional nozzle arrangements.
2Productivity
If growth rate is increased to 10 μm/h or more using HVPE or OVPE methods, then productivity is improved, but crystal precipitation occurs in the raw material gas introduction path causing defects
Solution Approach 1:
The gases are mixed together in the gas phase before reaching the board surface, in advance of the crystal growth process. This preliminary mixing ensures homogeneous distribution of reactants, preventing local supersaturation that would cause crystal precipitation in the introduction path, thereby enabling high growth rates without quality degradation.
Solution Approach 2:
The inclined nitrogen source nozzle acts as an intermediary device that facilitates thorough gas mixing in the intermediate region between the Group-III element source and the board. This intermediary mixing zone ensures uniform gas composition before deposition, preventing crystal precipitation while maintaining high growth rates.
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 configuration improves the mixing of gases, reduces crystal defects, and increases the transport efficiency of raw materials to the growth area, resulting in uniform gas distribution and enhanced growth rates.
Implementation Method 1
a raw material nozzle configured to spray a Group-III element-containing gas toward a board
Implementation Method 2
a nitrogen source nozzle configured to spray a nitrogen element-containing gas toward the board
Implementation Method 3
a mixing part in which a Group-III element-containing gas and a nitrogen element-containing gas are mixed together is formed
Implementation Method 4
a mixing part in which a Group-III element-containing gas and a nitrogen element-containing gas are mixed together is formed
Implementation Method 5
a heater configured to heat the raw material reaction chamber, the raw material nozzle, the nitrogen source nozzle, and the board-holding member in the raw material reaction chamber
Implementation Method 6
a rotation mechanism configured to rotate the board-holding member in the raw material reaction chamber
Implementation Method 7
a Group-III element metal (for example, Ga metal) and an oxidant (for example, H2O gas) are reacted with each other to generate a Group-III element metal oxide gas (Ga2O gas)
Implementation Method 8
GaN is grown from the Group-III element metal chloride and a nitrogen element-containing gas (for example, NH3 gas)
Data Source
AI summary
An apparatus for producing a Group-III nitride semiconductor crystal includes a raw material reaction chamber, a raw material reactor which is provided in the raw material reaction chamber and configured to generate a Group-III element-containing gas, a board-holding member configured to hold a board in the raw material reaction chamber, a raw material nozzle configured to spray the Group-III element-containing gas toward the board, a nitrogen source nozzle configured to spray a nitrogen element-containing gas toward the board, in which, in a side view seen in a direction perpendicular to a vertical direction, a spray direction of the nitrogen source nozzle intersects with a spray direction of the raw material nozzle before the board, and a mixing part in which the Group-III element-containing gas and the nitrogen element-containing gas are mixed together is formed around the intersection as a center, a heater, and a rotation mechanism.