Nitride Semiconductor Electrode with Silver and Platinum Group Metal Layers
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Solution Overview
Problem
Semiconductor light emitting devices using silver or silver alloys as electrodes face challenges in achieving high reflectivity, electrical characteristics, stability, and adhesiveness due to migration and chemical reactions, which limit their light extraction efficiency and reliability.
Innovation Solution
A stacked electrode structure comprising a silver or silver alloy first metal layer, a platinum group metal second metal layer, and a nickel third metal layer, where the third metal layer's thickness is equal to or greater than the second metal layer's thickness, and sinter processing is performed in an oxygen-nitrogen atmosphere to suppress migration and enhance adhesiveness and reflection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver or silver alloy is used as electrode material, then high reflectivity is achieved, but migration occurs reducing stability
Solution Approach 1:
The patent introduces intermediate metal layers (aluminum layer and titanium layer) between the silver layer and the semiconductor substrate. These intermediate layers act as mediators that prevent direct contact between silver and the substrate, thereby suppressing migration and chemical reactions while maintaining electrical conductivity and adhesion.
Solution Approach 2:
The patent employs a composite electrode structure consisting of multiple metal layers including silver layer, aluminum layer, and titanium layer. This composite structure combines the high reflectivity and electrical conductivity of silver with the adhesion properties of titanium and aluminum, thereby achieving both high reliability in terms of stability and adhesiveness simultaneously.
2Reliability
If silver or silver alloy is used as electrode material, then excellent electrical characteristics are achieved, but chemical reactions occur reducing stability
Solution Approach 1:
The patent introduces intermediate metal layers (aluminum layer and titanium layer) between the silver layer and the semiconductor substrate. These intermediate layers act as mediators that prevent direct contact between silver and the substrate, thereby suppressing migration and chemical reactions while maintaining electrical conductivity and adhesion.
Solution Approach 2:
The patent employs a composite electrode structure consisting of multiple metal layers including silver layer, aluminum layer, and titanium layer. This composite structure combines the high reflectivity and electrical conductivity of silver with the adhesion properties of titanium and aluminum, thereby achieving both high reliability in terms of stability and adhesiveness simultaneously.
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 maintains excellent reflection and electrical characteristics while improving stability and adhesiveness, resulting in high luminance, efficiency, and reliability of the semiconductor light emitting device.
Implementation Method 1
sinter processing is performed in an oxygen-nitrogen atmosphere to suppress migration and enhance adhesiveness and reflection characteristics
Implementation Method 2
sinter processing is performed in an oxygen-nitrogen atmosphere to suppress migration and enhance adhesiveness and reflection characteristics
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a stacked structure body and an electrode. The stacked structure body has a first conductivity type first semiconductor layer including a nitride-based semiconductor, a second conductivity type second semiconductor layer including a nitride-based semiconductor, and a light emitting layer provided between the first and second semiconductor layers. The electrode has first, second and third metal layers. The first metal layer is provided on the second semiconductor layer and includes silver or silver alloy. The second metal layer is provided on the first metal layer and includes at least one element of platinum, palladium, rhodium, iridium, ruthenium, osmium. The third metal layer is provided on the second metal layer. A thickness of the third metal layer along a direction from the first toward the second semiconductor layer is equal to or greater than a thickness of the second metal layer.