Plasma Nitrogen MOCVD Apparatus for Low-Temperature Group III Nitride Growth
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Solution Overview
Problem
Existing methods for producing Group III nitride semiconductors, such as MOCVD and MBE, face challenges including high growth temperatures, substrate bending, and high ammonia consumption, which hinder efficient mass production and result in low-quality crystalline semiconductors.
Innovation Solution
A plasma-based apparatus that uses a gas mixture of nitrogen and hydrogen gases converted into a plasma state, combined with an organometallic gas containing a Group III metal in a non-plasma state, to grow Group III nitride semiconductors at a lower temperature without the need for ammonia, employing a specific electrode and gas supply configuration to prevent charged particle interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MOCVD is used to grow Group III nitride semiconductors, then high-quality crystalline layers can be obtained, but high growth temperatures are required causing substrate bending and difficulty in growing high-In concentration InGaN layers
Solution Approach 1:
The invention changes the chemical parameters of the gas phase by using plasma-excited nitrogen species instead of molecular nitrogen, enabling nitride formation at lower temperatures. The plasma state alters the reactivity and bonding characteristics, allowing crystalline growth without high thermal energy input that causes substrate bending
Solution Approach 2:
The invention utilizes the phase transition of nitrogen from molecular gas phase to plasma state to enable low-temperature nitride formation. The plasma phase provides reactive nitrogen species that can incorporate into the crystal lattice at temperatures below conventional MOCVD requirements, preventing substrate deformation
2Productivity
If conventional MOCVD is used, then semiconductor layers can be formed, but large amounts of ammonia gas are consumed requiring detoxification equipment and incurring high running costs
Solution Approach 1:
The invention extracts and eliminates the ammonia gas component from the conventional MOCVD process, replacing it with plasma-excited nitrogen species. This removal of the harmful substance (ammonia) maintains the nitride formation capability while avoiding the need for detoxification equipment and reducing running costs
Solution Approach 2:
The invention introduces plasma as an intermediary medium to enable nitrogen incorporation without using ammonia. The plasma state acts as a mediator that provides reactive nitrogen species through alternative pathways, bypassing the need for ammonia-based chemistry and its associated environmental and cost issues
3Ease of manufacture
If plasma MOCVD is used as disclosed in Patent Document 1, then magnesium oxide film can be formed, but high-quality crystalline Group III nitride semiconductor cannot be obtained
Solution Approach 1:
The invention applies local quality control by optimizing the plasma generation conditions and gas composition specifically for nitride semiconductor formation. Rather than using generic plasma conditions that work for oxide formation, the invention tailors the plasma parameters (gas composition, power density, flow rates) to locally create the specific chemical environment needed for high-quality Group III nitride crystalline growth
Solution Approach 2:
The invention employs a composite approach by combining plasma excitation with specific organometallic precursor gases. This composite process integrates the reactive nitrogen species from plasma with the metalorganic sources of Group III elements, creating a synergistic system that achieves both low temperature operation and high crystalline quality that neither method could achieve alone
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
Enables the growth of high-quality Group III nitride semiconductors at lower temperatures, suitable for mass production, without the use of ammonia and its associated detoxification costs, while maintaining high crystallinity and reducing production costs.
Implementation Method 1
the second gas is converted into a plasma state, and the organometallic gas is supplied to the growth substrate. Since at least nitrogen gas is converted into the plasma state, the epitaxial growth of the Group III nitride semiconductor can be performed without elevating the substrate temperature
Data Source
AI summary
The production apparatus includes a shower head electrode, a susceptor for supporting a growth substrate, a first gas supply pipe, and a second gas supply pipe. The first gas supply pipe has at least one first gas exhaust outlet and supplies an organometallic gas containing Group III metal as a first gas, and the second gas supply pipe supplies a gas containing nitrogen gas as the second gas. The distance between the shower head electrode and the susceptor is greater than the distance between the first gas exhaust outlet of the first gas supply pipe and the susceptor.