Light Emitting Device Electrode Structure with Barrier Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The internal light-emitting efficiency of light-emitting diodes is degraded due to light absorption by electrodes and light-emitting layers, and the use of expensive gold for bonding pads increases costs.
Innovation Solution
A light-emitting device with an electrode structure comprising a bonding layer, a conductive layer with higher standard oxidation potential than the bonding layer, a mirror layer for reflecting light, and barrier layers to prevent interdiffusion and enhance adhesion and conductivity, while using a transparent conductive oxide layer and a semiconductor stacking layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mirror layer is provided under the electrode to reflect light, then light-emitting efficiency is improved, but device complexity increases
Solution Approach 1:
The patent combines the mirror layer function with the electrode structure by integrating a reflective layer directly into the electrode assembly. The electrode includes a conductive layer, a barrier layer, and a reflective layer that works together as a unified structure, eliminating the need for separate mirror components while maintaining light reflection functionality.
Solution Approach 2:
The electrode structure is designed to perform multiple functions simultaneously: electrical conduction through the conductive layer, oxidation prevention through the barrier layer, and light reflection through the reflective layer. This multi-functional design improves light-emitting efficiency without proportionally increasing device complexity.
2Reliability
If gold is used for the bonding pad to ensure conductivity and adhesion, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive gold bonding pads with a cost-effective multi-layer structure consisting of a conductive layer (e.g., aluminum or copper) and a barrier layer. This substitution significantly reduces material costs while maintaining adequate electrical conductivity and adhesion properties through the engineered layer combination.
Solution Approach 2:
The bonding pad structure uses composite materials - a conductive layer made of cheaper metals (aluminum, copper, or silver) combined with a barrier layer (such as titanium nitride or chromium) that prevents oxidation. This composite approach achieves the reliability of gold bonding pads at a fraction of the cost by leveraging the complementary properties of different materials.
3Ease of manufacture
If the electrode structure is simplified to reduce cost, then manufacturing cost decreases, but adhesion and conductivity may deteriorate
Solution Approach 1:
The electrode structure is segmented into distinct functional layers: a conductive layer for electrical conduction, a barrier layer for oxidation prevention and adhesion enhancement, and a reflective layer for light reflection. This segmentation allows each layer to be optimized for its specific function, ensuring that cost reductions in material selection do not compromise overall performance.
Solution Approach 2:
The patent optimizes the thickness and material composition parameters of each layer to achieve the desired balance between cost and performance. By carefully controlling the thickness of the barrier layer and selecting appropriate materials for the conductive layer, the structure maintains adequate adhesion and conductivity while using more cost-effective materials compared to traditional gold bonding pads.
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 solution enhances light-emitting efficiency by minimizing light absorption and reducing costs through optimized electrode design, improving adhesion and conductivity, and maintaining high reflectivity with a cost-effective material selection.
Implementation Method 1
the mirror layer under the electrode has been provided to solve the problem. When the route of the light extracted from the light-emitting layer is blocked by the electrode, the mirror can reflect but not absorbs the light
Implementation Method 2
a first barrier layer between the bonding layer and the conductive layer
Implementation Method 3
the conductive layer has higher standard oxidation potential than that of the bonding layer
Data Source
AI summary
A light-emitting device, comprising: a substrate; a semiconductor stacking layer comprising a first type semiconductor layer on the substrate, an active layer on the first semiconductor layer, and a second semiconductor layer on the active layer; and an electrode structure on the second semiconductor layer, wherein the electrode structure comprises a bonding layer, a conductive layer, and a first barrier layer between the bonding layer and the conductive layer; wherein the conductive layer has higher standard oxidation potential than that of the bonding layer.