Vertical Photo-Assisted MOCVD Layout for Uniform Epitaxial Growth
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Solution Overview
Problem
Existing MOCVD apparatuses face challenges in optimizing light field utilization efficiency and epitaxial uniformity, particularly in large-scale production, due to complex temperature-field and flow-field distributions and increased chamber structure complexity with the introduction of a light field.
Innovation Solution
A vertical photo-assisted MOCVD apparatus with a light field acting perpendicular to reactant gas flows, utilizing a rotating substrate susceptor and a horizontal layered showerhead to achieve uniform distribution of photo-generated reactants, with spatial separation of reactant generation and deposition processes, and a beam shaping system to optimize light field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a light field is introduced into the MOCVD chamber to improve reactant molecule cleavage efficiency, then epitaxial quality is improved, but chamber structure complexity increases
Solution Approach 1:
The reaction chamber is divided into distinct functional zones: a light field coupling chamber for photo-assisted reactant activation and a growth chamber for epitaxial deposition. This spatial segmentation allows the light field to act selectively on reactant gas flows without complicating the entire chamber structure, as the optical components are confined to a specific coupling region rather than requiring integration throughout the whole system.
Solution Approach 2:
A light field coupling chamber is introduced as an intermediary structure between the gas delivery system and the growth chamber. This coupling chamber serves as a transition zone where the light field interacts with reactant molecules before they enter the main growth region, thereby improving epitaxial quality while isolating the complexity of light field integration to a dedicated intermediate space rather than requiring modification of the entire chamber.
2Quantity of substance
If the light field acts on reactant gas flows to improve cleavage efficiency, then photo-generated reactants increase, but light source power requirements increase
Solution Approach 1:
The light field is concentrated to act locally on specific regions of the reactant gas flows within the light field coupling chamber, rather than uniformly illuminating the entire chamber. This localized action optimizes the interaction between light and reactant molecules, generating sufficient photo-generated reactants with reduced overall light source power by focusing energy only where needed for molecular cleavage.
Solution Approach 2:
The light field is introduced acting perpendicular to the direction of reactant gas flows, creating a three-dimensional interaction geometry. This dimensional arrangement maximizes the interaction path length between light and gas molecules within a compact volume, enhancing photo-generated reactant production efficiency and reducing the power requirements compared to conventional parallel illumination approaches.
3Productivity
If reactants are transported horizontally to the substrate, then mass transport efficiency improves, but temperature-field distribution complexity increases
Solution Approach 1:
The reaction chamber is segmented into a light field coupling chamber where horizontal reactant transport occurs and a growth chamber where vertical deposition takes place. This segmentation allows horizontal gas flow for efficient mass transport in the coupling chamber while the growth chamber maintains conditions optimized for uniform temperature distribution and epitaxial growth, thereby decoupling the conflicting requirements of transport efficiency and thermal uniformity.
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 apparatus reduces light source power requirements, simplifies design complexity, enhances safety, and achieves high uniformity in large-size photo-assisted MOCVD epitaxial growth by optimizing light and flow field coupling.
Implementation Method 1
A photo-assisted MOCVD apparatus can introduce a light field matching vibration mode of reactant molecules, such that cleavage efficiency of the reactant molecules can be improved through resonant absorption of energy of the light field by the reactant molecules
Implementation Method 2
exciting the reactants by the light field to produce photo-generated reactants in the light field coupling chamber
Implementation Method 3
beam shaping devices arranged in the light field coupling windows; the external light source is transmitted through the light beam transmission system and vertically enters the MOCVD reactor via the optical field coupling window
Implementation Method 4
a heating device arranged below the substrate susceptor
Implementation Method 5
a vacuum pump interface formed at a bottom of the chamber
Data Source
AI summary
A vertical photo-assisted metal organic chemical vapor deposition (MOCVD) apparatus and a deposition method using the same are provided. In the vertical photo-assisted MOCVD apparatus, a light field vertically acts on the layered reactant gas flows, and interaction paths between the light field and the reactant gas flows are short, which reduces the required light source power, lowers the design complexity of the photo-assisted MOCVD apparatus, improves the safety of the photo-assisted MOCVD apparatus and the utilization efficiency of the light field power. In the vertical photo-assisted MOCVD apparatus, through self-rotation and revolution of the growth substrates with the substrate susceptor, active reactants generated by the light field are uniformly distributed between the growth substrates and within each growth substrate in the growth chamber, thereby achieving high uniformity large-size photo-assisted MOCVD epitaxial growth.