Patterned Electrode Stack for Nitride LED Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor light emitting devices using III group nitride based semiconductors face challenges in achieving high outward luminous efficiency and manufacturing yield, particularly in large diameter devices with uniform light emission.
Innovation Solution
The semiconductor light emitting device comprises a substrate with an n-type semiconductor layer, an active layer, and a p-type semiconductor layer, along with specific metal and transparent electrode layer configurations, including patterned metal layers and an insulating film, which enhance light extraction and reduce heat damage, thereby improving luminous efficiency and manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional electrode structure is used, then the device structure is simple, but the outward luminous efficiency is insufficient
Solution Approach 1:
The electrode structure is divided into multiple functional layers: a first electrode layer for electrical contact, a reflective layer for light extraction, and an insulating layer for electrical isolation. This segmentation allows each layer to perform its specific function optimally, improving outward luminous efficiency while maintaining manageable complexity through modular design
Solution Approach 2:
A transparent conductive oxide layer is introduced as an intermediary between the reflective electrode layer and the semiconductor layers. This intermediate layer serves dual functions: maintaining electrical conductivity for charge transport while allowing light to pass through to the external environment, thereby improving light extraction efficiency without compromising electrical performance
2Reliability
If the p-side electrode is removed for reliability improvement, then wire bonding reliability increases, but the device structure becomes more complex
Solution Approach 1:
The p-side electrode is completely removed from the device structure to eliminate the source of reliability issues during wire bonding. This extraction of the problematic component improves wire bonding reliability, while the remaining electrode structure on the n-side is simplified and optimized to perform both electrical and optical functions
Solution Approach 2:
The remaining electrode structure is designed to perform multiple functions: providing electrical contact, serving as a reflective surface for light extraction, and enabling wire bonding without the reliability issues associated with p-side electrodes. This multi-functionality compensates for the removed component while maintaining overall device performance
3Loss of energy
If a simple metal layer configuration is used, then the manufacturing process is simpler, but light extraction efficiency is insufficient
Solution Approach 1:
The electrode structure employs composite material layers including reflective metals (such as aluminum or silver), transparent conductive oxides, and insulating materials. This composite structure enhances light extraction efficiency by combining the reflective properties of metals with the optical transparency and electrical conductivity of oxides, while the standardized layering process maintains manufacturing simplicity
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 described configuration improves outward luminous efficiency and manufacturing yield by effectively extracting light from the active layer and reducing heat damage, enabling the production of large diameter devices with uniform light emission.
Implementation Method 1
effectively extracting light from the active layer and reducing heat damage, improving luminous efficiency
Implementation Method 2
specific metal and transparent electrode layer configurations, including patterned metal layers and an insulating film, which enhance light extraction
Implementation Method 3
an insulating film which is placed on the transparent electrode layer and the second metal layer
Data Source
AI summary
A semiconductor light emitting device includes a first metal layer placed on the p-type semiconductor layer on the substrate, and includes a first pattern width W1; a second metal layer on the first metal layer; a transparent electrode layer on the second metal layer and the p type semiconductor layer, and has an opening patterned with a second pattern width W2 on the second metal layer; an insulating film the transparent electrode layer and the second metal layer, and has an opening patterned with third pattern width W3 on the second metal layer; a reflective stacked film on the insulating film, and has an opening patterned with third pattern width W3 on the second metal layer; a third metal layer on the second metal layer of an opening patterned with the reflective stacked film and third pattern width W3; and a fourth metal layer on the third metal layer.