Semiconductor Light-Emitting Element With Segmented Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor light-emitting elements face a decrease in light extraction efficiency due to the large light absorption by pad electrodes required for wire bonding, which are typically made of materials with low reflectance to minimize light absorption.
Innovation Solution
The design incorporates a transparent electrode in ohmic contact with a conductivity type layer, a smaller lower electrode for reduced light absorption, and a reflective portion within the insulation layer to enhance light reflection and extraction efficiency, with the upper electrode being larger for wire bonding and having a higher reflectance than the lower electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pad electrode with large area is formed for wire bonding connection, then the connection reliability is improved, but the light absorption by the pad electrode increases, resulting in decreased light extraction efficiency
Solution Approach 1:
The pad electrode is divided into two separate electrodes: an upper pad electrode for wire bonding connection and a lower pad electrode for electrical connection to the transparent electrode. This segmentation allows the upper electrode to be optimized for connection reliability while the lower electrode can be minimized to reduce light absorption.
Solution Approach 2:
Different regions of the electrode structure are assigned different functions and properties. The upper pad electrode has large area for reliable wire bonding, while the lower pad electrode has minimal area to reduce light absorption. The reflective portion is positioned specifically in regions where it can reflect light back into the light-emitting layer without interfering with electrical connections.
2Loss of energy
If the lower pad electrode area is minimized to reduce light absorption, then light extraction efficiency is improved, but the electrical connection reliability may be compromised
Solution Approach 1:
The electrical connection path is separated from the wire bonding connection. The lower pad electrode provides the electrical connection to the transparent electrode with minimal area for reduced light absorption, while the upper pad electrode provides the wire bonding connection with adequate area for reliability.
Solution Approach 2:
The upper pad electrode acts as an intermediary between the lower pad electrode and the wire bonding connection. It receives the electrical connection from the lower electrode and provides the interface for wire bonding, allowing the lower electrode to be minimized without compromising overall connection reliability.
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 decreases light absorption by the pad electrodes and improves light extraction efficiency by efficiently reflecting light, while maintaining strong adhesion and reducing defects like peeling.
Implementation Method 1
a reflective portion for reflecting at least a portion of light transmitted through a region of the transparent electrode not in contact with the lower electrode
Implementation Method 2
a transparent electrode in ohmic contact with the second conductivity type layer
Implementation Method 3
a transparent electrode in ohmic contact with the second conductivity type layer
Data Source
AI summary
A semiconductor light-emitting element includes a semiconductor laminated structure including a light-emitting layer sandwiched between first and second conductivity type layers for extracting an emitted light from the light-emitting layer on a side of the second conductivity type layer, a transparent electrode in ohmic contact with the second conductivity type layer, an insulation layer formed on the transparent electrode, an upper electrode for wire bonding formed on the insulation layer, a lower electrode that penetrates the insulation layer, is in ohmic contact with the transparent electrode and the electrode for wire bonding, and has an area smaller than that of the upper electrode in top view, and a reflective portion for reflecting at least a portion of light transmitted through a region of the transparent electrode not in contact with the lower electrode.