Light Emitting Device Ohmic Layer Patterning
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Solution Overview
Problem
Existing light emitting devices face issues with current leakage and increased driving voltage due to damage of the ohmic layer during the etching process for patterning, which affects light extraction efficiency and reliability.
Innovation Solution
A light emitting device with a light extraction pattern formed on an ohmic layer, utilizing a second ohmic layer with a pattern that has a different binding energy than the first ohmic layer, allowing for in-situ formation without damaging the ohmic layer and serving as an etch stop layer, thereby preventing current leakage and maintaining stable driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light extraction pattern is formed by etching the ohmic layer, then light extraction efficiency is improved, but the ohmic layer is damaged causing current leakage and increased driving voltage
Solution Approach 1:
The patent divides the ohmic layer into two separate layers: a first ohmic layer that maintains electrical contact with the light emitting structure, and a second ohmic layer that receives the light extraction pattern. This segmentation allows the pattern to be formed without damaging the first ohmic layer, thus preventing current leakage while improving light extraction efficiency.
Solution Approach 2:
The second ohmic layer acts as an intermediary between the first ohmic layer and the light extraction pattern. It serves as an etch stop layer that protects the first ohmic layer during pattern formation, while still allowing the pattern to be formed on its surface for improved light extraction.
2Illumination intensity
If the ohmic layer is patterned to improve light extraction, then light extraction efficiency increases, but manufacturing complexity increases due to additional layers and processes
Solution Approach 1:
The patent combines the functions of electrical conduction and light extraction into a two-layer ohmic structure. The first ohmic layer provides electrical contact while the second ohmic layer provides the light extraction pattern, merging multiple functions into a unified structure that reduces overall device complexity.
Solution Approach 2:
The patent changes the binding energy parameter of the second ohmic layer relative to the first ohmic layer. This parameter change allows selective etching of the second layer while preserving the first layer, enabling pattern formation without increasing manufacturing complexity through additional protective steps.
3Device complexity
If a single ohmic layer is used, then device structure is simple, but light extraction efficiency is limited and current leakage occurs when patterned
Solution Approach 1:
The patent segments the single ohmic layer into two distinct layers with different functions. The first layer maintains electrical properties while the second layer enables light extraction patterning, thus improving light extraction efficiency without compromising structural simplicity.
Solution Approach 2:
The two-layer ohmic structure provides multi-functionality: the first layer serves as the electrical contact layer while the second layer serves as both an electrical contact layer and a platform for light extraction patterns. This universality improves light extraction efficiency while maintaining structural efficiency.
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 effectively removes failure factors such as current leakage and increased driving voltage, ensuring stable operation and improved light extraction efficiency by forming the light extraction pattern on the ohmic layer using the difference in binding energy without degrading the ohmic characteristics.
Implementation Method 1
utilizing a second ohmic layer with a pattern that has a different binding energy than the first ohmic layer, allowing for in-situ formation without damaging the ohmic layer and serving as an etch stop layer
Implementation Method 2
A light emitting device (LED) includes a p-n junction diode having a characteristic of converting electric energy into light energy. When forward voltage is applied to the LED, electrons of an n layer are bonded with holes of a p layer, so that energy corresponding to an energy gap between a conduction band and a valance band may be generated. This energy is mainly realized as heat or light, and the LED emits the energy as the light.
Data Source
AI summary
Disclosed are a light emitting device, a light emitting device package, a lighting system and a manufacturing method of light emitting device. The light emitting device includes a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first and second conductive semiconductor layers; a first ohmic layer over the light emitting structure; and a second ohmic layer including a pattern over the first ohmic layer.