Semiconductor Optical Device Wiring Electrode Composite Structure
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Solution Overview
Problem
Semiconductor light-emitting diodes and solar cells face reduced light extraction and collection efficiencies due to electrode portions blocking light, and existing methods to improve efficiency, such as surface roughening, can lead to increased peeling of wiring electrode portions.
Innovation Solution
A semiconductor optical device with a wiring electrode portion having a metal layer and a conductive hard film, where the line width is between 2 μm and 5 μm, and the conductive hard film is harder than the metal layer, with a vacant space between the electrode and semiconductor layer, reducing peeling and enhancing light extraction or collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the line width of the wiring electrode portion is reduced to improve light extraction efficiency, then the light extraction efficiency improves, but the wiring electrode portion peels off more easily
Solution Approach 1:
The wiring electrode portion is constructed as a composite structure with a metal layer and a conductive hard film layer. The metal layer (e.g., Al, Cu, Au, Ag) provides electrical conductivity, while the conductive hard film (e.g., TiN, TaN, WN) provides mechanical strength and peeling resistance. This composite structure allows the electrode to maintain both high light extraction efficiency (through reduced line width) and high reliability (through enhanced peeling resistance).
Solution Approach 2:
Different layers of the wiring electrode portion are assigned different local qualities: the metal layer is optimized for electrical conductivity and light reflection, while the conductive hard film is optimized for mechanical strength and adhesion. This local differentiation allows each layer to perform its specific function optimally, resolving the contradiction between light extraction efficiency and peeling resistance.
2Productivity
If surface roughening is applied to improve light extraction efficiency, then the light extraction efficiency improves, but the wiring electrode portion peels off more easily
Solution Approach 1:
The conductive hard film is formed on the metal layer before the surface roughening process. This preliminary action protects the metal layer from direct exposure to the roughening treatment (e.g., nitric acid immersion), preventing degradation of the metal layer's adhesion properties while still allowing the semiconductor layer surface to be roughened for improved light extraction.
Solution Approach 2:
The conductive hard film acts as an intermediary layer between the metal layer and the roughened semiconductor layer surface. It mediates the interaction between the metal layer and the roughening process, protecting the metal layer from direct contact with etchants while maintaining the beneficial surface roughness for light extraction efficiency.
3Productivity
If the line width of the wiring electrode portion is reduced to improve light collection efficiency, then the light collection efficiency improves, but the wiring electrode portion peels off more easily
Solution Approach 1:
The same composite structure of metal layer and conductive hard film is applied to improve light collection efficiency in photodetectors and solar cells. The reduced line width allows more light to reach the active layer, while the conductive hard film ensures the thin electrode structure maintains sufficient mechanical strength and adhesion.
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 significantly improves light extraction or collection efficiency while reducing the peeling ratio of the wiring electrode portion, making it more durable and efficient compared to conventional devices.
Implementation Method 1
a conductive hard film on the metal layer... significantly improves light extraction or collection efficiency while reducing the peeling ratio of the wiring electrode portion
Implementation Method 2
Surface roughening of a light emitting surface and a light receiving surface is known as such a technique for improving light extraction efficiency or light collecting efficiency
Implementation Method 3
light received at pn junctions is converted into electrical energy due to the photovoltaic effect
Implementation Method 4
light-emitting semiconductor light-emitting diodes emit light by converting electric current flown through p-n junctions into light energy
Data Source
AI summary
Provided is a semiconductor optical device with light extraction efficiency or light collecting efficiency higher than that of conventional devices and with a reduced peeling ratio of a wiring electrode portion, and a method of manufacturing the same. In the semiconductor optical, a wiring electrode portion 120 is provided on a surface of a semiconductor layer 110 that serves as a light emitting surface or a light receiving surface, the line width W1 of the wiring electrode portion 120 is 2 μm or more and 5 μm or less, the wiring electrode portion 120 has a metal layer 121 on the semiconductor layer 110 and a conductive hard film 122 on the metal layer 121, and the conductive hard film 122 is harder than the metal layer 121.