Semiconductor Light Emitting Device Barrier Layer
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Solution Overview
Problem
Semiconductor light emitting devices face challenges in achieving high light extraction efficiency and reliability due to issues with metal reflecting layers deteriorating from contact with transparent conducting layers, leading to reduced reflectivity and ion migration, which affects their performance in lighting applications.
Innovation Solution
A semiconductor light emitting device is constructed with a transparent conducting layer, a dielectric film, and a metal reflecting layer, where a barrier layer is interposed between the transparent conducting layer and the metal reflecting layer to prevent direct contact and deterioration, while the dielectric film with angular dependence and multilayer structure enhances reflectivity and light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a metal reflecting layer is used to improve light extraction efficiency, then reflectivity increases, but the metal layer deteriorates due to contact with the transparent conducting layer, reducing reliability
Solution Approach 1:
A barrier layer is introduced between the transparent conducting layer and the metal reflecting layer to prevent direct contact. This intermediary layer stops ion migration and chemical reactions that cause deterioration, while still allowing the metal layer to perform its light reflection function effectively.
Solution Approach 2:
The electrode structure uses a composite multi-layer configuration combining transparent conducting material, barrier layer material, and metal reflecting material. This composite structure leverages the advantages of each material: transparency and conductivity from the first layer, protection from the barrier layer, and high reflectivity from the metal layer.
2Productivity
If a dielectric multilayer is used to enhance reflection, then light extraction efficiency improves, but the structure complexity increases
Solution Approach 1:
The dielectric multilayer for optical reflection and the barrier layer for chemical protection are merged into a single integrated electrode structure. The dielectric layers serve dual purposes: enhancing light extraction through optical interference effects and providing structural framework for the electrode assembly.
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 configuration increases the reliability and light output power of the semiconductor light emitting device by preventing metal reflecting layer deterioration and improving light extraction efficiency, even when light is incident at slanting angles, thus addressing the limitations of existing devices.
Implementation Method 1
the dielectric multilayer has an angular dependence of reflection
Implementation Method 2
the reflecting layer 2916...can provide total reflection effect
Implementation Method 3
ITO is generally used which has good ohmic contact characteristics and high transmittance
Implementation Method 4
good ohmic contact characteristics
Implementation Method 5
metal reflecting layer such as Al...can improve the vertical reflection efficiency
Data Source
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AI summary
A semiconductor light emitting device includes a semiconductor structure (11), a transparent electrically-conducting layer (13), a dielectric film (4), and a metal reflecting layer (22). The semiconductor structure (11) includes an active region (8). The transparent electrically-conducting layer (13) is formed on the upper surface of the semiconductor structure (11). The dielectric film (4) is formed on the upper surface of the transparent electrically-conducting layer (13). The metal reflecting layer (22) is formed on the upper surface of the dielectric film (4). The dielectric film (4) has at least one opening (21) whereby partially exposing the transparent electrically-conducting layer (13). The transparent electrically-conducting layer (13) is electrically connected to the metal reflecting layer (22) through the opening (21). A barrier layer (24) is partially formed and covers the opening (21) so that the barrier layer (24) is interposed between the transparent electrically-conducting layer (13) and the metal reflecting layer (22).