Reflective Layer System Adhesion in Optoelectronic Semiconductors
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Solution Overview
Problem
Optoelectronic semiconductor bodies with reflective layer systems face a risk of metal layer delamination due to inadequate adhesion, which can render components unusable, especially in mass production.
Innovation Solution
Incorporating a second radiation-permeable layer with an adhesion-improving material, such as nitrogen-containing compounds or transparent conducting oxides, between the first radiation-permeable layer and the metal layer to enhance adhesion, thereby reducing the risk of delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a metal layer is applied directly to the first radiation-permeable layer to achieve high reflectivity, then the reflectivity is improved, but the adhesion of the metal layer deteriorates leading to delamination risk
Solution Approach 1:
A second radiation-permeable layer comprising an adhesion-improving material is introduced between the first radiation-permeable layer and the metal layer. This intermediary layer serves as a mediator that provides both optical permeability and improved adhesion properties, allowing the metal layer to adhere reliably while maintaining the high reflectivity function of the overall reflective layer system.
2Reliability
If a second radiation-permeable layer with adhesion-improving material is added between the first radiation-permeable layer and the metal layer, then the adhesion is improved, but the device complexity increases
Solution Approach 1:
The second radiation-permeable layer is designed with local quality by using materials that specifically enhance adhesion properties at the interface with the metal layer, while maintaining radiation permeability. This localized functional enhancement allows the system to achieve improved adhesion without requiring a complete redesign of the entire reflective layer system, thus limiting the increase in overall complexity.
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 effectively improves the adhesion of the metal layer, reducing the likelihood of delamination and maintaining high reflectivity over a large angular range, thus minimizing the proportion of defective components in mass production.
Implementation Method 1
The second radiation-permeable layer contains an adhesion-improving material or consists of the adhesion-improving material. The metal layer is applied directly to the adhesion-improving material of the second radiation-permeable layer. The adhesion of the metal layer is improved in comparison with the adhesion on the first dielectric material.
Implementation Method 2
light rays which extend in the semiconductor layer sequence at a flat angle towards the reflective layer system are totally reflected on the boundary surface between the semiconductor layer sequence and the first radiation-permeable layer
Implementation Method 3
Light rays which do not fulfill the reflection conditions for total reflection and penetrate into the first radiation-permeable layer are reflected back in the direction of the semiconductor layer sequence e.g. by means of the metal layer.
Data Source
AI summary
An optoelectronic semiconductor body (1) having an active semiconductor layer sequence (10) and a reflective layer system (20) is described. The reflective layer system (20) comprises a first radiation-permeable layer (21), which adjoins the semiconductor layer sequence (10), and a metal layer (23) on the side of the first radiation-permeable layer (21) facing away from the semiconductor layer sequence (10). The first radiation-permeable layer (21) contains a first dielectric material. Between the first radiation-permeable layer (21) and the metal layer (23) there is disposed a second radiation-permeable layer (22) which contains an adhesion-improving material. The metal layer (23) is applied directly to the adhesion-improving material. The adhesion-improving material differs from the first dielectric material and is selected such that the adhesion of the metal layer (23) is improved in comparison with the adhesion on the first dielectric material.