Semiconductor Light Emitting Device Transparent Electrode and DBR Layer
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Solution Overview
Problem
Semiconductor light emitting devices face challenges in achieving improved luminous flux and reliability due to limitations in light extraction efficiency and physical impacts during manufacturing processes.
Innovation Solution
A semiconductor light emitting device is designed with a light emitting structure, a transparent electrode layer, a transparent protective layer, and a distributed Bragg reflector (DBR) layer, along with an insulating layer and electrode pads, where the refractive index of the protective layer is lower than the insulating layer, and the electrode pads are formed with unique inner walls to minimize physical damage and enhance light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light emitting device structure is used, then the device is simple to manufacture, but light extraction efficiency is insufficient
Solution Approach 1:
The device is divided into multiple functional layers including a light emitting layer, a transparent electrode layer, a transparent protective layer, and a DBR layer. Each layer serves a specific function: the light emitting layer generates light, the transparent electrode layer conducts electricity while allowing light passage, the transparent protective layer protects against physical damage, and the DBR layer reflects light to improve extraction efficiency. This segmentation allows each component to be optimized independently for its specific function.
Solution Approach 2:
The device employs composite material structures, particularly the combination of transparent protective layer and DBR layer with different refractive indices. The transparent protective layer has a refractive index lower than the insulating layer, creating a gradient that enhances light extraction. The DBR layer uses alternating high and low refractive index materials to create constructive interference for light reflection, improving overall light extraction efficiency.
2Reliability
If the transparent protective layer has high refractive index, then light extraction is improved, but physical damage during manufacturing increases
Solution Approach 1:
The transparent protective layer is designed with specific local properties: it has a refractive index lower than the insulating layer to create optimal optical conditions for light extraction, while simultaneously providing sufficient mechanical protection. The layer is positioned specifically between the transparent electrode layer and the DBR layer, where it can locally manage both optical and mechanical requirements without affecting other parts of the device.
Solution Approach 2:
The transparent protective layer acts as a cushioning layer that protects the underlying transparent electrode layer and light emitting structure from physical damage during subsequent manufacturing processes. By placing this protective layer beforehand, the device can withstand etching and other processing steps without damaging the sensitive light emitting components.
3Ease of manufacture
If conventional electrode pad structure is used, then manufacturing is simple, but electrical properties degrade over time
Solution Approach 1:
The transparent protective layer is formed to cover and protect the transparent electrode layer and electrode pad structure before final device assembly and operation. This preliminary protection prevents degradation from environmental factors such as moisture and oxygen exposure, maintaining electrical properties over time. The protective layer is applied beforehand to prevent rather than repair potential degradation.
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 enhances light extraction efficiency and reliability by reducing physical impacts during manufacturing and preventing degradation of electrical properties, resulting in improved luminous flux and extended device lifespan.
Implementation Method 1
a distributed Bragg reflector (DBR) layer disposed on the transparent protective layer and covering at least a part of the transparent electrode layer
Implementation Method 2
a refractive index of the transparent protective layer is lower than a refractive index of the insulating layer
Data Source
AI summary
Provided is a semiconductor light emitting device which includes: a light emitting structure including a plurality of semiconductor layers and configured to generate and emit light to an outside of the light emitting structure; a transparent electrode layer disposed on the light emitting structure; a transparent protective layer disposed on the transparent electrode layer; a distributed Bragg reflector (DBR) layer disposed on the transparent protective layer and covering at least a part of the transparent electrode layer; and at least one electrode pad connected to the transparent electrode layer through a hole or via.