Semiconductor LED Structure for Lift-Off and Leakage Reduction
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Solution Overview
Problem
Current display technologies, such as LCDs and AMOLEDs, face issues with slow response time, limited flexibility, short lifespan, and high manufacturing costs, while semiconductor light-emitting devices struggle with low light extraction efficiency and high surface leakage current.
Innovation Solution
A display apparatus is designed with a semiconductor light-emitting device structure that includes a porous material for mechanical lift-off, a conductive intermediate layer with varying impurity concentrations, and a passivation layer to reduce surface leakage and enhance light extraction, thereby improving luminous efficiency and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor light-emitting devices are separated from growth substrate using conventional methods, then separation is achieved, but the devices are damaged due to heat or chemicals
Solution Approach 1:
A porous intermediate layer is introduced between the semiconductor light-emitting device and the growth substrate. This intermediate layer serves as a mediator that enables mechanical lift-off separation without exposing the device to harmful heat or chemicals. The porous structure allows for selective etching and clean separation while protecting the device integrity.
Solution Approach 2:
The patent replaces conventional thermal or chemical separation methods with a mechanical lift-off method. By using a porous intermediate layer that can be mechanically removed, the process substitutes harmful thermal/chemical fields with a gentle mechanical separation approach, preventing device damage.
2Reliability
If conventional separation methods are used, then separation is achieved, but manufacturing cost increases
Solution Approach 1:
By replacing expensive thermal or chemical separation processes with a mechanical lift-off method using a porous intermediate layer, the manufacturing cost is reduced. The mechanical method requires simpler equipment and fewer costly materials while achieving reliable separation.
Solution Approach 2:
The use of a porous intermediate layer provides a cost-effective solution for separation. The porous structure enables easy mechanical removal and selective etching, simplifying the manufacturing process and reducing costs compared to conventional methods.
3Illumination intensity
If light extraction efficiency is not optimized, then device structure is simple, but light extraction efficiency is low
Solution Approach 1:
A porous layer is introduced in the device structure to enhance light extraction efficiency. The porous structure increases the surface area and creates multiple interfaces that scatter and extract light more effectively, improving illumination intensity without requiring complex external optical systems.
Solution Approach 2:
The porous layer is strategically positioned in specific regions of the device to optimize light extraction at critical interfaces. This localized approach enhances light extraction efficiency where needed most while keeping the overall device structure relatively simple.
4Reliability
If surface leakage current is not reduced, then device structure is simple, but surface leakage current is high
Solution Approach 1:
A passivation layer is applied specifically to the surface regions where leakage current occurs. This localized treatment addresses the leakage problem at the surface without requiring complex modifications to the bulk device structure, maintaining simplicity while improving reliability.
Solution Approach 2:
The passivation layer serves as an intermediary between the semiconductor surface and the external environment, blocking leakage current paths while allowing the device to maintain its fundamental simple structure. This intermediate layer provides the necessary electrical isolation without complex redesign.
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 prevents damage to semiconductor light-emitting devices during separation, enhances light extraction efficiency, and reduces surface leakage current, leading to improved performance and cost-effectiveness in display technology.
Implementation Method 1
a layer of a porous material capable of being electro-polished may be disposed and separated by a mechanical lift-off method when the semiconductor light-emitting device is separated from the growth substrate
Implementation Method 2
reflection from a side surface of the semiconductor light-emitting device may be reduced by an intermediate layer including conductive impurities
Implementation Method 3
the semiconductor light-emitting device may further include a passivation layer surrounding a side surface of the first conductive semiconductor layer, the conductive semiconductor layer, and the active layer
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A display apparatus according to the present invention comprises a plurality of semiconductor light-emitting devices, wherein at least one of the semiconductor light-emitting devices comprises: a first conductive electrode and a second conductive electrode; a first conductive semiconductor layer having the first conductive electrode arranged thereon; a second conductive semiconductor layer overlapping the first conductive semiconductor layer and having the second conductive electrode arranged thereon; an active layer arranged between the first conductive semiconductor layer and the second conductive semiconductor layer; an intermediate layer arranged on the second conductive semiconductor layer; a protrusion, made of an electro-polishable porous material, on the intermediate layer; and an undoped semiconductor layer arranged between the intermediate layer and the protrusion. Furthermore, the intermediate layer comprises a first layer including second conductive impurities and a second layer having a higher concentration of the second conductive impurities than the first layer, wherein the first layer and the second layer are sequentially and repetitively stacked.