Nitride Semiconductor Layer Growth via Dynamic V/III Ratio Control
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Solution Overview
Problem
The existing methods for manufacturing nitride semiconductor devices face challenges due to high strain energy and crystal quality reduction caused by lattice constant and thermal expansion coefficient differences between nitride semiconductor layers and their substrates, leading to issues with crack generation and nitrogen vacancies.
Innovation Solution
A method is developed to grow multilayer films of III-V group nitride semiconductors by adjusting the flow rates of V group and III group element raw material gases and carrier gases in a reaction furnace, allowing for alternating growth of GaN and AlN layers at optimized V/III ratios specific to each layer, thereby reducing nitrogen vacancies and improving crystal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the V/III ratio is increased to reduce nitrogen vacancies in GaN layer, then crystal quality of GaN layer is improved, but parasitic reactions increase in AlN layer formation
Solution Approach 1:
The patent applies dynamics by making the V/III ratio adjustable and variable during the growth process. The system transitions from a static, fixed V/III ratio approach to a dynamic, layer-specific control mechanism where the ratio can be optimized for each semiconductor layer type (GaN vs AlN) independently, allowing crystal quality improvement without permanent harmful side effects
Solution Approach 2:
The patent implements local quality by applying different V/III ratios to different layers within the same semiconductor structure. Specifically, a higher V/III ratio is used for GaN layers to reduce nitrogen vacancies and improve crystal quality, while a lower V/III ratio is used for AlN layers to suppress parasitic reactions. This spatially differentiated approach allows each layer to have optimal growth conditions tailored to its specific material requirements
2Ease of manufacture
If a fixed V/III ratio is used for growing both GaN and AlN layers, then process simplicity is maintained, but crystal quality and material efficiency deteriorate
Solution Approach 1:
The invention transforms the manufacturing process from a static, one-size-fits-all approach to a dynamic, adaptive process. The V/III ratio is no longer fixed but becomes a controllable parameter that can be adjusted in real-time based on which layer is being grown, enabling optimal crystal quality while maintaining reasonable process complexity through automated control
Solution Approach 2:
The patent applies local quality by implementing layer-specific optimization where different regions of the semiconductor structure (GaN layers vs AlN layers) receive different V/III ratios during growth. This allows each local region to have the optimal chemical environment for its specific material composition, significantly improving overall crystal quality and material efficiency compared to a uniform approach
3Quantity of substance
If the V/III ratio is increased for AlN layer growth, then nitrogen supply is improved, but parasitic reactions that do not contribute to film formation increase
Solution Approach 1:
The patent applies local quality by providing nitrogen supply optimization specifically where needed (in GaN layers with higher V/III ratio) while using a lower V/III ratio in AlN layers where excess nitrogen causes parasitic reactions. This spatially differentiated nitrogen supply strategy improves overall material efficiency by preventing nitrogen waste in AlN layers while ensuring adequate nitrogen availability in GaN layers
Solution Approach 2:
The invention converts the potential harm of excess nitrogen (which causes parasitic reactions in AlN layers) into a benefit by selectively applying high nitrogen supply only where it is beneficial (GaN layers) while controlling it in regions where it would be harmful (AlN layers). This transforms what would be a universal problem into a targeted solution that improves material efficiency
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 enables the growth of nitride semiconductor devices with high crystal quality and improved breakdown voltage, as demonstrated by significantly reduced leak currents and enhanced material efficiency.
Implementation Method 1
a method for manufacturing a nitride semiconductor device that grows a multilayer film of a III-V group nitride semiconductor in a reaction furnace into which a III group element raw material gas and a V group element raw material gas are introduced
Data Source
AI summary
The invention provides a method for manufacturing a nitride semiconductor device that grows a multilayer film of a III-V group nitride semiconductor in a reaction furnace into which a III group element raw material gas and a V group element raw material gas are introduced, the method including: growing a first nitride semiconductor layer at a first raw material gas flow rate of the V group element raw material gas and a first carrier gas flow rate; and growing a second nitride semiconductor layer at a second raw material gas flow rate of the V group element raw material gas lower than the first raw material gas flow rate and a second carrier gas flow rate higher than the first carrier gas flow rate, wherein the first nitride semiconductor layer and the second nitride semiconductor layer are stacked.