Dual Passivation Layer for Light Emitting Diodes
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Solution Overview
Problem
Existing light emitting devices face challenges in preventing current leakage and absorbing shock stress during the laser lift off process, particularly due to the brittleness of GaN semiconductor materials, which can lead to mechanical instability and increased risk of cracking.
Innovation Solution
A dual-structured passivation layer comprising an inorganic layer with high dielectric constant and mechanical strength, and an organic layer with low elastic modulus to absorb impact energy, is implemented. The inorganic layer enhances dielectric and heat-resistant properties, while the organic layer serves as a stress buffer, optimizing mechanical stability and light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic passivation layer is used to prevent current leakage, then dielectric properties are improved, but mechanical brittleness increases and shock absorption capability deteriorates
Solution Approach 1:
The patent applies composite materials by combining an inorganic passivation layer (such as SiO2, Si3N4, or Al2O3) with an organic passivation layer (such as polyimide or acrylic resin). The inorganic layer provides high dielectric constant for preventing current leakage, while the organic layer provides low elastic modulus for absorbing shock stress during laser lift off process. This composite structure resolves the contradiction between electrical performance and mechanical durability.
Solution Approach 2:
The patent applies local quality by assigning different functional properties to different layers: the inorganic layer is positioned to provide dielectric protection where current leakage prevention is critical, while the organic layer is positioned to provide mechanical cushioning where shock absorption is needed. Each layer has optimized local properties tailored to its specific function in the passivation system.
2Stability of the object's composition
If the passivation layer has high mechanical strength to resist cracking, then structural stability is improved, but light extraction efficiency deteriorates due to increased refractive index mismatch
Solution Approach 1:
The composite passivation layer structure enables simultaneous achievement of structural stability and light extraction efficiency. The inorganic layer provides structural stability with its high mechanical strength, while the organic layer has refractive index properties that reduce mismatch with the semiconductor layer, thereby maintaining or improving light extraction efficiency despite the presence of the structurally critical inorganic layer.
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
The dual-structured passivation layer effectively prevents current leakage and absorbs shock stress, enhancing the mechanical stability and thermal resistance of the light emitting device, reducing the likelihood of cracking and improving overall device performance during the laser lift off process.
Implementation Method 1
a second passivation layer on the first passivation layer and has an elastic modulus of 2.0 to 4.0 GPa
Implementation Method 2
capable of preventing current leakage while effectively absorbing shock
Implementation Method 3
a first passivation layer which surrounds the light emitting semiconductor layer and comprises inorganic material
Data Source
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AI summary
Disclosed is a light emitting device. The light emitting device comprises a light emitting semiconductor layer comprising a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer, a first passivation layer on the light emitting semiconductor layer, and a second passivation layer on the first passivation layer and has an elastic modulus of 2.0 to 4.0 GPa.