MOCVD Reactor Duct Height Variation for Film Uniformity
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Solution Overview
Problem
MOCVD reactors face challenges in achieving uniform film thickness and efficiency when scaling up the susceptor, leading to non-uniform film deposition due to varying reaction gas conditions across the substrate.
Innovation Solution
The MOCVD reactor design features a duct with a specific height configuration that monotonically diminishes in certain sections, allowing for improved mixing of reaction gases and maintaining a laminar flow, enabling uniform film deposition and increased efficiency by rotating the heating member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the susceptor is scaled up to heat many substrates at once, then film-deposition efficiency is improved, but the distance between upstream and downstream ends increases leading to non-uniform reaction gas conditions and non-uniform film thickness
Solution Approach 1:
The duct height is designed to vary along the reaction gas flow direction, creating different local conditions in different regions. Specifically, the duct height monotonically diminishes from the upstream end to a first point, then stays constant from the first point to the downstream end. This local variation in duct height compensates for the distance effect in scaled-up susceptors, maintaining uniform reaction gas conditions and film thickness across all substrates regardless of susceptor size.
2Device complexity
If the duct height is uniform along the reaction gas flow, then the structure is simple, but the reaction gas conditions become non-uniform across the susceptor length
Solution Approach 1:
The duct height parameter is changed along the reaction gas flow direction to achieve uniform reaction gas conditions. The duct height monotonically diminishes from the upstream end to a first point, then remains constant from the first point to the downstream end. This parameter variation compensates for the increased distance in scaled-up susceptors, maintaining stable and uniform reaction gas conditions without requiring complex additional components.
3Productivity
If the susceptor size is increased to process large diametric span substrates, then productivity improves, but the difference in reaction gas conditions between upstream and downstream ends increases
Solution Approach 1:
The duct height is designed with local variation along the reaction gas flow direction to compensate for the increased distance in large-scale susceptors. The height monotonically diminishes from the upstream end to a first point, then stays constant from the first point to the downstream end. This creates locally optimized conditions that maintain reaction gas consistency across the entire large diametric span susceptor, ensuring reliable and uniform film deposition across all 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
This design ensures uniform film thickness and enhanced deposition efficiency, even when scaling up the susceptor, by maintaining a linear relationship between the carrying surface position and film deposition rate, and promoting gas mixing and laminar flow.
Implementation Method 1
thermally decomposing the vaporized Group-III compound and reacting the decomposition products with a Group-V gas to deposit a film on the substrate
Implementation Method 2
the reaction gas flow uniformly along the substrate surfaces
Implementation Method 3
The heating member is rotatable with the carrying surface facing toward the duct interior
Implementation Method 4
The duct has a first channel and a second channel, and the first and second channels join together on the side upstream from the upstream end of the carrying surface of the heating member
Data Source
AI summary
Affords MOCVD reactors with which, while deposited films are uniformized in thickness, film deposition efficiency can be improved. An MOCVD reactor (1) is furnished with a susceptor (5) and a duct (11). The susceptor (5) has a carrying surface for heating and carrying substrates (20). The duct (11) is for conducting reaction gas (G) to the substrates (20). The susceptor (5) is rotatable with the carrying surface fronting on the duct (11) interior. The duct (11) has channels (11b) and (11c), which merge on the duct end upstream of Point A4. The height of the duct (11) running along the reaction gas (G) flow direction monotonically diminishes heading toward the duct downstream end from Point P1 to Point P2, stays constant from Point P2 to Point P3, and monotonically diminishes heading downstream from Point P3. Point P1 lies upstream of Point A4, while Point P3 lies on the susceptor (5).