Semiconductor Light-Emitting Element With Transparent Conductive Adhesion Layer
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Solution Overview
Problem
Semiconductor light-emitting devices face challenges in improving light extraction efficiency and adhesiveness between layers, particularly in flip chip attachment configurations.
Innovation Solution
A semiconductor light-emitting element is designed with a specific structure including a group-III nitride semiconductor layer, a light-emitting layer, a transparent conductive layer, a transparent insulating layer with penetration holes, and a metal reflective layer, where the transparent conductive layers are composed of indium zinc oxide and the insulating layer is made of silicon dioxide, optimized for improved adhesiveness and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a metallic reflective film is formed on the group-III nitride semiconductor layer to reflect light back to the substrate side, then light extraction efficiency is improved, but adhesiveness between layers deteriorates
Solution Approach 1:
The patent uses a composite structure consisting of a transparent conductive layer (ITO or IZO) combined with a metallic reflective film (silver). The transparent conductive layer serves as an adhesion promoter between the semiconductor layer and the metallic film, while the metallic film provides high reflectance. This composite material approach allows simultaneous achievement of good adhesiveness and high light extraction efficiency.
Solution Approach 2:
The transparent conductive layer acts as an intermediary layer between the group-III nitride semiconductor layer and the metallic reflective film. This intermediate layer prevents direct contact between the semiconductor and metal, maintaining adhesiveness while still allowing the metallic film to function as a reflector for light extraction.
2Loss of energy
If materials are tried to be used for forming each layer to improve light extraction efficiency, then light output is increased, but adhesiveness between layers becomes insufficient
Solution Approach 1:
The patent specifies particular material compositions and thickness parameters for each layer. The transparent conductive layer has a controlled thickness (not explicitly specified but optimized) to balance optical transparency and mechanical adhesion. The metallic reflective film thickness is also controlled to provide sufficient reflectance while maintaining flexibility in the composite structure. These parameter optimizations ensure both light extraction and adhesiveness.
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 configuration enhances adhesiveness between layers and increases light extraction efficiency, particularly in flip chip attachment, by utilizing the properties of indium zinc oxide and silicon dioxide to reflect and transmit light effectively.
Implementation Method 1
a metal reflective layer composed of a metal material having reflectance to light emitted from the light-emitting layer
Implementation Method 2
a first transparent conductive layer that is composed of a material having transparency to light emitted from the light-emitting layer and a conductive property
Data Source
AI summary
A semiconductor light-emitting element (1) including: an n-type semiconductor layer (140); a light-emitting layer (150); a p-type semiconductor layer (160); a transparent conductive layer (170) laminated on the p-type semiconductor layer; a reflective film (180) which is composed of a material having optical transparency to light emitted from the light-emitting layer and an insulating property and is laminated on the transparent conductive layer; a p-conductive body (200) which penetrates the reflective film and is electrically connected to the transparent conductive layer; an n-electrode (310) electrically connected to the n-type semiconductor layer; and a p-electrode (300) having a p-adhesion layer (301) which is laminated on the reflective film, is electrically connected to the other end of the p-conductive body, and is composed of the same material as that for the transparent conductive layer and a p-metal reflective layer (302) which is laminated on the p-adhesion layer.