Gallium Oxide Mist CVD Flow Rectification for Uniform Film Growth
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Solution Overview
Problem
The mist CVD method faces challenges in maintaining in-plane uniformity of film thickness and film forming rate, especially with larger substrates, due to exponential decrease in mist supply and non-uniform film distribution, which existing solutions like substrate scanning and rotation fail to fully address, and can complicate apparatus design and maintenance.
Innovation Solution
A method and apparatus that rectifies the flow of mist and carrier gas to flow from the outer circumference to the center of the substrate within a film forming chamber using a middle plate, combined with a mist-forming unit, carrier gas supply, and exhaust system, ensuring uniform film thickness and increased forming rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heating is performed in a film forming chamber for film formation by thermal reaction, then the film can be formed on the substrate, but the amount of supplied mist decreases exponentially and the film forming rate decreases
Solution Approach 1:
The process is divided into two separate chambers: a mist generation chamber where mist is produced without heating, and a film formation chamber where heating occurs. This segmentation allows mist generation and thermal reaction to occur independently, preventing the exponential decrease in mist supply while maintaining film formation quality.
Solution Approach 2:
Mist is generated and prepared in advance in the mist generation chamber before being supplied to the film formation chamber. This preliminary action ensures that sufficient mist is available for high-rate film formation without the constraints of in-chamber heating limitations.
2Manufacturing precision
If scanning and rotating the substrate is implemented to improve uniformity, then in-plane uniformity can be partially improved, but the initial cost of the apparatus increases and maintenance becomes complicated
Solution Approach 1:
The complex scanning and rotating mechanisms are eliminated by extracting the uniformity control function to the mist supply system itself. The carrier gas-driven mist flow provides uniform distribution without requiring mechanical substrate movement, simplifying the apparatus while maintaining uniformity.
Solution Approach 2:
Mechanical substrate scanning and rotation are replaced with a gas-flow-based mist delivery system. The carrier gas transports mist uniformly across the substrate surface, achieving the same uniformity goal without mechanical complexity.
3Area of stationary object
If the diameter of the substrate is increased, then larger area coverage is achieved, but in-plane uniformity of film thickness becomes more difficult to maintain
Solution Approach 1:
The carrier gas serves as an intermediary that distributes mist uniformly across large substrate areas. The gas flow pattern ensures consistent mist delivery from the center to the edges of large-diameter substrates, maintaining uniformity regardless of substrate size.
Solution Approach 2:
A pneumatic system using carrier gas flow replaces mechanical approaches for achieving uniform coverage. The gas flow dynamics are optimized to distribute mist uniformly across the entire substrate surface, enabling consistent film thickness on large-diameter substrates.
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 method and apparatus achieve high in-plane uniformity of film thickness and improved film forming rate, particularly for large substrates, through a simple and efficient configuration that suppresses non-uniformity and enhances mist utilization.
Implementation Method 1
a raw material solution containing gallium is misted in a mist-forming unit to generate mist
Implementation Method 2
supplying a carrier gas for transferring the mist to the mist-forming unit
Implementation Method 3
rectifying flow of the mist and the carrier gas supplied to a surface of a substrate in the film forming chamber so as to flow along the surface of the substrate
Implementation Method 4
heat-treating the rectified mist to form a film on the substrate
Implementation Method 5
form a film on the substrate
Implementation Method 6
exhausting waste gas upward from the substrate
Data Source
AI summary
A method for producing a gallium oxide semiconductor film by a mist CVD method, including, a mist-forming step in which a raw material solution containing gallium is misted in a mist-forming unit to generate mist, a carrier gas supply step of supplying a carrier gas for transferring the mist to the mist-forming unit, a transferring step of transferring the mist from the mist-forming unit to a film forming chamber using the carrier gas via a supply pipe connecting the mist-forming unit and the film forming chamber, a rectification step of rectifying flow of the mist and the carrier gas supplied to a surface of a substrate in the film forming chamber so as to flow along the surface of the substrate, a film forming step of heat-treating the rectified mist to form a film on the substrate, and an exhaust step of exhausting waste gas upward from the substrate.