Pyrolytic Graphite Reflector Layout for Uniform Vapor Phase Heating
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Solution Overview
Problem
The durability of reflectors in vapor phase growth apparatuses is compromised due to thermal stress caused by temperature gradients, leading to potential damage and reduced efficiency in heating uniformity and film quality.
Innovation Solution
The use of a disk-shaped upper reflector made of pyrolytic graphite with a notched portion and through hole, and a disk-shaped lower reflector made of silicon carbide with reduced thickness, enhances thermal shock resistance and durability, improving heating efficiency and uniformity while preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a reflector is provided below the heater to improve heating efficiency, then heating efficiency is improved, but thermal stress occurs due to temperature gradient which reduces durability
Solution Approach 1:
The patent changes the material parameter of the reflector from conventional materials to pyrolytic graphite, which has superior thermal shock resistance properties. This material substitution allows the reflector to withstand the temperature gradient and thermal stress generated during heating operations, thereby maintaining durability while preserving heating efficiency.
Solution Approach 2:
The patent employs pyrolytic graphite, a composite material with unique layered structure and exceptional thermal properties. This material combines high thermal conductivity with high thermal shock resistance, enabling the reflector to efficiently conduct heat while resisting thermal stress, thus resolving the contradiction between heating efficiency and durability.
2Reliability
If the reflector is made thicker to improve durability, then durability is improved, but heating uniformity deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter of the reflector to a specific range that balances durability and heating uniformity. By precisely controlling the thickness parameter and selecting pyrolytic graphite material, the reflector achieves sufficient mechanical strength while maintaining good thermal conductivity for uniform heating.
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 improves the durability and heating efficiency of the reflectors, maintaining temperature uniformity and reducing the need for frequent replacements, thereby enhancing the quality and consistency of semiconductor films.
Implementation Method 1
a disk-shaped upper reflector provided below the in-heater and formed of pyrolytic graphite
Implementation Method 2
a disk-shaped lower reflector provided below the upper reflector, formed of silicon carbide
Implementation Method 3
formed of pyrolytic graphite... formed of a material having a thermal shock resistance of 1000 kW/m or more
Data Source
AI summary
A vapor phase growth apparatus of embodiments includes: a reactor; a holder provided in the reactor to place a substrate thereon; an annular out-heater provided below the holder; an in-heater provided below the out-heater; a disk-shaped upper reflector provided below the in-heater and formed of pyrolytic graphite; and a disk-shaped lower reflector provided below the upper reflector, formed of silicon carbide, and having a thickness smaller than that of the upper reflector.