Semiconductor Light Emitting Device with Ag Electrode and Nitrogen Barrier
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Solution Overview
Problem
Semiconductor light emitting devices using silver (Ag) as a reflecting electrode face issues with migration and instability, leading to low reliability and non-uniform light extraction efficiency due to Ag's high reflectance and conductivity.
Innovation Solution
A semiconductor light emitting device configuration is developed, including a first semiconductor layer, a light emitting unit, a second semiconductor layer, a reflecting electrode with Ag, an insulative oxide layer, and a nitrogen-containing layer, where the oxide layer is formed on the reflecting electrode and subjected to heat treatment in an oxygen atmosphere, followed by the formation of a nitrogen-containing layer, which suppresses Ag migration and enhances contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If silver (Ag) is used as a reflecting electrode to increase light extraction efficiency, then light extraction efficiency is improved, but Ag migration occurs easily leading to low reliability
Solution Approach 1:
A nitrogen-containing layer is introduced as an intermediary between the silver reflecting electrode and the semiconductor layer. This layer acts as a diffusion barrier that prevents Ag migration into the semiconductor while maintaining the high reflectance of the Ag electrode, thus preserving light extraction efficiency while improving reliability.
Solution Approach 2:
The electrode structure is designed as a composite multi-layer system comprising a nitrogen-containing layer and a silver layer. This composite structure combines the high reflectance property of Ag with the migration-blocking property of the nitrogen-containing layer, achieving both high light extraction efficiency and high reliability.
2Reliability
If silver (Ag) is used as a reflecting electrode, then conductivity is improved, but stable characteristics are difficult to obtain
Solution Approach 1:
The nitrogen-containing layer serves as a protective intermediary that stabilizes the Ag electrode composition by preventing Ag atoms from migrating into the semiconductor layer. This barrier layer ensures the electrode maintains its compositional stability and electrical characteristics over time.
3Illumination intensity
If Ag is used as electrode material, then light extraction efficiency is improved, but uniform light emission is difficult to achieve due to migration
Solution Approach 1:
The nitrogen-containing layer acts as a uniform barrier across the entire electrode area, preventing localized Ag migration that would cause non-uniform light emission. This ensures consistent electrical and optical properties throughout the device, achieving uniform light emission.
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 achieves a low and uniform contact resistance, suppresses Ag migration, and maintains high reliability while ensuring uniform light emission at a low operating voltage, improving the overall performance and stability of the semiconductor light emitting device.
Implementation Method 1
the oxide layer is formed on the reflecting electrode and subjected to heat treatment in an oxygen atmosphere
Implementation Method 2
a nitrogen-containing layer, which suppresses Ag migration and enhances contact resistance
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a light emitting unit, a second semiconductor layer, a reflecting electrode, an oxide layer and a nitrogen-containing layer. The first semiconductor layer is of a first conductivity type. The light emitting unit is provided on the first semiconductor layer. The second semiconductor layer is provided on the light emitting unit and is of a second conductivity type. The reflecting electrode is provided on the second semiconductor layer and includes Ag. The oxide layer is provided on the reflecting electrode. The oxide layer is insulative and has a first opening. The nitrogen-containing layer is provided on the oxide layer. The nitrogen-containing layer is insulative and has a second opening communicating with the first opening.