Group III Nitride Semiconductor Sputtering Process
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Solution Overview
Problem
Existing methods for manufacturing Group III nitride semiconductors using the sputtering method face challenges in achieving high film formation rates while maintaining excellent crystallinity, as high substrate temperatures improve crystallinity but reduce film formation rates, and low temperatures enhance rates but compromise crystallinity.
Innovation Solution
A method involving a two-step sputtering process where the substrate temperature is initially set high to enhance dislocation migration and then lowered to increase film formation rate, allowing for efficient formation of Group III nitride semiconductor crystals with excellent crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate temperature is set to a relatively high temperature during sputtering, then the crystallinity of the GaN film is improved, but the film formation rate extremely decreases
Solution Approach 1:
The film formation process is divided into multiple stages with different substrate temperatures. The first stage uses a relatively high temperature (700-900°C) to form an initial layer with good crystallinity, while the second stage uses a lower temperature (400-600°C) to achieve high film formation rate. This segmentation allows each stage to optimize for its specific purpose, resolving the contradiction between crystallinity and productivity.
Solution Approach 2:
The high-temperature first stage performs a preliminary action of forming an initial GaN layer with excellent crystallinity and serving as a template for subsequent growth. This preliminary layer preparation enables the second stage to achieve high deposition rates while maintaining good crystallinity, as the template already provides the necessary crystal structure.
2Productivity
If the substrate temperature is set to a relatively low temperature during sputtering, then the film formation rate is improved, but the crystallinity of the GaN film deteriorates
Solution Approach 1:
The process is segmented into two temperature stages: a high-temperature first stage for crystallinity development, and a low-temperature second stage for high-rate deposition. This segmentation allows the system to achieve both high productivity and good crystallinity by performing each function at the optimal temperature for that specific goal.
Solution Approach 2:
The first high-temperature stage performs the preliminary action of establishing a crystalline template structure. Once this template is formed, the second stage can proceed at lower temperatures with high deposition rates, as the crystal structure is already established by the preliminary action of the first stage.
3Manufacturing precision
If a single high temperature is used throughout the sputtering process, then excellent crystallinity is achieved, but the production yield is lowered due to extremely low film formation rate
Solution Approach 1:
The sputtering process is segmented into two temperature phases: a first phase at high temperature (700-900°C) for a predetermined period to establish crystallinity, and a second phase at lower temperature (400-600°C) for high-rate completion of the film. This segmentation resolves the time-loss issue by limiting high-temperature exposure to only what is necessary for crystallinity, then accelerating production in the second phase.
Solution Approach 2:
The first high-temperature stage performs the preliminary action of establishing the crystal structure in a predetermined period. After this preliminary crystallinity establishment, the second stage completes the film formation at higher rates, thereby achieving both excellent crystallinity and improved production yield.
4Productivity
If a single low temperature is used throughout the sputtering process, then high film formation rate is achieved, but the crystallinity of the GaN film deteriorates with increased dislocation density
Solution Approach 1:
The process is segmented into a high-temperature first stage for crystallinity development and a low-temperature second stage for high-rate deposition. This segmentation allows the system to achieve both high productivity and good crystallinity by performing each function at the optimal temperature for that specific goal, preventing dislocation accumulation.
Solution Approach 2:
The first high-temperature stage performs the preliminary action of establishing a template crystal structure with low dislocation density. Once this template is formed, the second stage can proceed at lower temperatures with high deposition rates without accumulating significant dislocations, as the template already provides a stable crystal structure.
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 stable and efficient formation of Group III nitride semiconductor crystals with high crystallinity and desired thickness at a high film formation rate, improving the production yield and light emission characteristics of light-emitting devices.
Implementation Method 1
a sputtering step of forming a single-crystalline Group III nitride semiconductor on a substrate by a reactive sputtering method
Implementation Method 2
the loop of initial dislocation is enhanced by migration, and the dislocation density is reduced
Data Source
AI summary
A method for manufacturing a Group III nitride semiconductor of the present invention includes a sputtering step of forming a single-crystalline Group III nitride semiconductor on a substrate by a reactive sputtering method in a chamber in which a substrate and a Ga element-containing target are disposed, wherein said sputtering step includes respective substeps of: a first sputtering step of performing a film formation of the Group III nitride semiconductor while setting the temperature of the substrate to a temperature T1; and a second sputtering step of continuing the film formation of the Group III nitride semiconductor while lowering the temperature of the substrate to a temperature T2 which is lower than the temperature T1.