Mushroom-like Susceptor for MOCVD Induction Heating
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Solution Overview
Problem
Conventional MOCVD reactors using induction heating face issues with susceptor levitation and inefficient heat transfer, leading to low growth efficiency and non-uniform thin-film deposition at high temperatures due to Eddy currents and magnetic flux interactions, which require gas inlets to be kept far from the susceptor, causing reactant decomposition and recirculation.
Innovation Solution
A mushroom-like susceptor device with a horizontal plate and perpendicular vertical rod integrated for induction heating, surrounded by a thermal insulation structure, allowing gas inlets to be placed closer to the wafer surface, reducing Eddy current interactions and enhancing heat transfer efficiency by occupying the magnetic flux zone, thus maintaining higher energy efficiency and uniform deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas inlets are kept close to the wafer surface to improve growth efficiency, then deposition efficiency improves, but gas inlets overheating and reactant decomposition occurs due to magnetic flux
Solution Approach 1:
A susceptor plate is introduced as an intermediary component between the induction coil and the gas inlets. The susceptor plate absorbs and shields the magnetic flux, preventing it from directly heating the gas inlets while allowing the induction heating to effectively heat the wafer through the susceptor plate. This mediator structure enables gas inlets to be positioned closer to the wafer surface without overheating.
2Loss of energy
If susceptor levitation is prevented to improve heat transfer efficiency, then energy efficiency improves, but conventional induction heating cannot achieve this without additional constraints
Solution Approach 1:
The susceptor plate acts as a counterweight structure that balances the levitation force generated by Eddy currents. The plate's mass and structural design provide a counteracting force that prevents the susceptor from levitating away from the induction coil, ensuring stable contact and efficient heat transfer while maintaining energy efficiency.
3Temperature
If conventional induction heating is used to achieve high temperature deposition, then deposition temperature increases, but susceptor levitation occurs due to Eddy current interactions
Solution Approach 1:
The susceptor is designed as a composite structure combining a susceptor plate with vertical rods. This composite design optimizes both the heating efficiency and the mechanical stability. The plate provides thermal contact with the wafer while the vertical rods provide structural reinforcement to resist levitation forces, enabling high-temperature deposition without susceptor instability.
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 solution effectively addresses levitation issues and enhances energy efficiency, allowing for higher growth rates and better film homogeneity by maximizing power transfer from the induction heater and minimizing the need for inert gases, resulting in improved deposition quality and uniformity.
Implementation Method 1
an induction coil will generate an alternating magnetic flux, and this alternating magnetic flux will induce Eddy currents on the susceptor according to Faraday's Law
Implementation Method 2
an induction coil will generate an alternating magnetic flux, and this alternating magnetic flux will induce Eddy currents on the susceptor according to Faraday's Law
Implementation Method 3
heating by an induction heater
Implementation Method 4
an induction coil will generate an alternating magnetic flux
Implementation Method 5
surrounded by a thermal insulation structure
Data Source
AI summary
A susceptor device for a chemical vapor deposition (CVD) reactor including metal organic CVD (MOCVD) used in the semiconductor industry. The susceptor device particularly is used with induction heating and includes a horizontal plate adapted for holding one or more wafers and a vertical rod around which the induction heating coils are disposed. A screw system and an insulator can further be used. This design helps prevent undesired levitation and allows for the gas injectors of the reactors to be placed closer to the wafer for deposition during high-temperature deposition processes at susceptor surface temperatures of about 1500° C. or higher.