GaN Vapor Epitaxy Magnesium Oxide Doping for Stable p-Type Growth
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Solution Overview
Problem
In vapor phase epitaxy methods not using organic metal as the gallium raw material, such as Halide Vapor Phase Epitaxy (HVPE), it is difficult to dope magnesium due to challenges in controlling its supply amount, as magnesium metal evaporates excessively or reacts uncontrollably with furnace components.
Innovation Solution
A gallium nitride vapor phase epitaxy apparatus that uses a magnesium-based oxide, heated within a specific temperature range, to supply magnesium into the reactor vessel, ensuring a stable and controlled magnesium supply, thereby enabling consistent magnesium doping without the reactivity issues associated with magnesium metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If magnesium metal is used for doping, then magnesium can be supplied into the reactor vessel, but magnesium evaporates excessively and supply amount cannot be controlled
Solution Approach 1:
The patent changes the physical and chemical parameters of the magnesium source by using magnesium oxide instead of magnesium metal. This parameter change allows for stable supply control through temperature management, as the magnesium oxide decomposes at a controlled rate to release magnesium vapor at a constant rate, resolving the contradiction between supplying magnesium and controlling its quantity.
Solution Approach 2:
The patent creates an inert environment by using a halogen-containing gas atmosphere that reacts with magnesium oxide to form stable intermediates. This inert environment prevents uncontrolled evaporation and reactions, allowing for reliable and controlled magnesium supply during the epitaxy process.
2Quantity of substance
If organic metal such as Cp2Mg is used for doping, then magnesium can be supplied, but it reduces prior to reaction causing carbon contamination
Solution Approach 1:
The patent extracts the harmful carbon component from the doping process by replacing organic metal compounds with inorganic magnesium oxide. This extraction eliminates the source of carbon contamination while maintaining the ability to supply magnesium for doping, as the magnesium oxide decomposes to release pure magnesium vapor without carbon byproducts.
Solution Approach 2:
The patent uses magnesium oxide as a disposable, stable precursor that decomposes completely during the process to release magnesium and oxygen, with no persistent harmful residues. This replaces the problematic organic metals that leave carbon contaminants, providing a clean doping source.
3Object-generated harmful factors
If vapor phase epitaxy not using organic metal is used, then carbon contamination is avoided, but magnesium doping becomes difficult
Solution Approach 1:
The patent introduces a halogen-containing gas as an intermediary that facilitates magnesium release from magnesium oxide. This intermediary reacts with magnesium oxide to form volatile magnesium halide species that can be transported and deposited, enabling magnesium doping in the carbon-free vapor phase epitaxy process without using organic metals.
Solution Approach 2:
The patent changes the chemical parameters of the system by introducing halogen-containing gases that react with magnesium oxide to enable magnesium vaporization and transport. This parameter change makes magnesium doping feasible in the inorganic vapor phase epitaxy process while maintaining the advantage of avoiding carbon contamination.
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 approach allows for precise magnesium doping in gallium nitride, achieving p-type semiconductor growth with excellent crystallinity and controlled magnesium concentration, comparable to organic metal-based methods like MOVPE, while avoiding carbon contamination and enhancing productivity.
Implementation Method 1
the magnesium-based oxide is heated by the first heating unit in the first temperature range. The magnesium-based oxide thereby reduces, and the third raw material gas containing magnesium can thereby be supplied into the reactor vessel
Implementation Method 2
The magnesium-based oxide is stable and has lower reactivity as compared to magnesium metal. Thus, a magnesium supply amount within the third raw material gas can be controlled to be constant
Implementation Method 3
vapor phase epitaxy methods not using organic metal as gallium raw material, such as Halide Vapor Phase Epitaxy (HVPE) and vapor phase epitaxy using gallium vapor as its raw material
Data Source
AI summary
A gallium nitride vapor phase epitaxy apparatus capable of doping magnesium is provided. The apparatus is used in vapor phase epitaxy not using organic metal as a gallium raw material. The apparatus comprises a reactor vessel and a wafer holder. The apparatus comprises a first raw material gas supply pipe configured to supply a first raw material gas containing gallium. The apparatus comprises a second raw material gas supply pipe configured to supply a second raw material gas, which contains nitrogen and configured to react with the first raw material gas. The apparatus comprises a third raw material gas supply pipe configured to supply a third raw material gas containing magnesium. The third raw material gas supply pipe is configured capable of placing a magnesium-based oxide on its supply path. The apparatus comprises a first heating unit configured to heat the magnesium-based oxide in a first temperature range.