Linear Showerhead for GaN Growth Preventing Pre-Reactions
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Solution Overview
Problem
Current showerheads for growing GaN are limited in their ability to prevent pre-reactions, resulting in poor crystal quality and low production capacity, making them unsuitable for mass production and industrialization due to thermal expansion mismatches and inadequate gas mixing.
Innovation Solution
A linear showerhead design featuring three independent gas bases with specific gas passage arrangements that isolate and eject reaction gases effectively, preventing pre-reactions and ensuring homogeneous gas distribution, allowing for the production of high-quality GaN thick films across various sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional showerheads are used for GaN growth, then production capacity can be increased, but pre-reactions occur at nozzles causing thermal expansion mismatch and nozzle damage
Solution Approach 1:
The showerhead is divided into multiple independent gas bases (first gas base, second gas base, third gas base), each with separate gas passages and nozzles. This segmentation allows different gases to be delivered through isolated pathways, preventing pre-reactions at the nozzles while maintaining high production capacity through parallel gas delivery channels.
Solution Approach 2:
An isolation gas (such as nitrogen) is introduced through the second gas base to act as an intermediary between reaction gases. This isolation gas prevents direct contact between reactive gases at the nozzles, eliminating pre-reactions and thermal expansion damage while allowing continuous operation for high productivity.
2Manufacturing precision
If showerheads are designed for small-scale single crystal production, then crystal quality can be maintained, but production capacity remains low and cost is high
Solution Approach 1:
The showerhead design with multiple gas bases and configurable gas passages can accommodate different production scales and crystal sizes. The same structure serves both high-quality single crystal growth and mass production needs by adjusting gas flow parameters and nozzle configurations, eliminating the need for separate specialized equipment.
Solution Approach 2:
The invention transitions from single-point or small-area gas delivery to a distributed multi-dimensional gas distribution system through multiple gas bases and passages. This allows homogeneous gas mixing across large substrate areas while maintaining the precise control needed for high crystal quality, enabling scaling from laboratory to industrial production.
3Productivity
If showerheads are designed for large-scale multi-piece production, then production capacity increases, but crystal quality deteriorates due to pre-reactions and poor gas homogeneity
Solution Approach 1:
The reaction chamber is divided into multiple gas delivery zones through separate gas bases, each with independent gas passages. This segmentation enables precise control of gas composition and flow in different spatial regions, ensuring homogeneous gas distribution across large substrate areas while preventing pre-reactions that would degrade crystal quality.
Solution Approach 2:
Isolation gas introduced through the second gas base acts as a mediator to prevent pre-reactions between reactive gases in large-scale production. This allows maintaining high production capacity with multiple substrates while preserving crystal quality through controlled gas phase separation until gases reach the substrate surface.
4Manufacturing precision
If reaction gases are mixed before reaching nozzles, then homogeneous gas distribution can be achieved, but pre-reactions occur causing nozzle deposition and damage
Solution Approach 1:
Different reaction gases are delivered through separate, segmented gas passages in different gas bases until they reach the substrate vicinity. This spatial segmentation prevents premature mixing and pre-reactions at nozzles, while the coordinated delivery from multiple bases ensures homogeneous gas distribution across the substrate surface.
Solution Approach 2:
An isolation gas is used as an intermediary to separate reactive gas streams through different gas bases. This prevents direct contact between reactive gases in the gas phase (avoiding pre-reactions and nozzle deposition) while still achieving homogeneous mixing at the substrate surface where the reaction should occur.
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
The design enhances the universality and production capacity of GaN thick films, stabilizes the flow field, reduces nozzle deposition, and promotes the industrialization of GaN single crystals by preventing pre-reactions and ensuring homogeneous gas distribution.
Implementation Method 1
The second gas base is configured to circulate an isolation gas. The isolation gas flows through the second central gas passages, enters the second gaps from the second nozzles, and is ejected from the first gaps.
Implementation Method 2
One reaction gas flows through the first central gas passages and is ejected from the first nozzles. Another reaction gas flows through the third central gas passages and is ejected from the third nozzles.
Implementation Method 3
In promoting the industrialization of GaN thick films and massively producing high-quality GaN thick films, the key rests in that a stable laminar flow field needs to be obtained in a reaction chamber.
Data Source
AI summary
A linear showerhead for growing GaN, including a first gas base, a second gas base, and a third gas base. First central gas passages are disposed in the middle of the first gas base. A first gap is disposed between two adjacent first central gas passages. A first nozzle is disposed at the bottom of a first central gas passage. The second gas base is disposed on the first gas base. Second central gas passages are disposed in the middle of the second gas base. A second gap is disposed between two adjacent second central gas passages. Two sides of a second central gas passage are provided with a second nozzle. The third gas base includes third central gas passages. A third central gas passage penetrates a first gap and a second gap. A third nozzle is disposed at the bottom of a third central gas passage.