Nitride Epitaxy Structure for Crack-Resistant Light-Emitting Elements
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face issues such as cracks, warpage, bowing, fractures, and breakages due to differing thermal expansion coefficients of their material layers, affecting luminous efficiency.
Innovation Solution
A method of manufacturing a light-emitting element structure that includes a substrate, nucleation, buffer, first and second nitride layers, and semiconductor layers, where the first nitride layer has a smaller film thickness and lower growth pressure than the second nitride layer, enhancing structural integrity and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light-emitting element structure with different material layers is used, then the structure can achieve light emission through electron-hole recombination, but cracks, warpage, bowing, fractures, and breakages occur due to different thermal expansion coefficients of materials
Solution Approach 1:
The patent introduces a multi-layer nitride structure (first nitride layer and second nitride layer) with different thicknesses and growth pressures to segment the stress distribution across the light-emitting element. This segmentation allows each layer to handle specific stress ranges, preventing catastrophic failure while maintaining light emission functionality.
Solution Approach 2:
The patent changes physical parameters of the nitride layers, specifically controlling film thickness (first nitride layer has smaller thickness than second nitride layer) and growth pressure (first nitride layer has lower growth pressure than second nitride layer). These parameter changes optimize the stress distribution and thermal expansion mismatch, reducing defects while maintaining luminous efficiency.
2Ease of manufacture
If layers with different thermal expansion coefficients are stacked, then the light-emitting element structure can be formed with necessary functional layers, but defects such as cracks, warpage, bowing, fractures, and breakages increase under temperature changes
Solution Approach 1:
The patent optimizes manufacturing parameters by controlling the film thickness and growth pressure of each nitride layer during epitaxial growth. The first nitride layer is grown with lower pressure and smaller thickness, while the second nitride layer is grown with higher pressure and larger thickness, creating a gradient structure that minimizes thermal stress and reduces manufacturing defects.
Solution Approach 2:
The patent employs a composite nitride layer structure where the first and second nitride layers work together as a composite system. This composite structure combines the advantages of different thicknesses and growth conditions to achieve both ease of manufacture and high manufacturing precision by reducing thermal expansion mismatches.
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 effectively reduces defects and improves luminous efficiency by minimizing cracks, warpage, and fractures, while enhancing epitaxial quality and reducing dislocation defect density.
Implementation Method 1
a first nitride layer being in contact with the buffer layer above the buffer layer; form a second nitride layer being in contact with the first nitride layer above the first nitride layer
Implementation Method 2
A conventional light-emitting diode (LED) is a kind of electroluminescent semiconductor light-emitting element structure that operates by recombining electrons and holes in a light-emitting layer to generate light with energy corresponding to its energy level
Data Source
AI summary
A method of manufacturing a light-emitting element, including: provide a substrate; form a nucleation layer above the substrate; form a buffer layer above the nucleation layer; form a first nitride layer being in contact with the buffer layer above the buffer layer; form a second nitride layer being in contact with the first nitride layer above the first nitride layer; form a first semiconductor layer above the second nitride layer; form a light-emitting layer above the first semiconductor layer; form a second semiconductor layer above the light-emitting layer. The light-emitting layer is adapted to emit light when electrons and holes recombine. A film thickness of the first nitride layer is smaller than a film thickness of the second nitride layer, and a growth pressure of the first nitride layer is smaller than a growth pressure of the second nitride layer.