Micro-LED Structure Using Ion Isolation to Avoid Mesa Etching
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Solution Overview
Problem
Conventional micro-LED manufacturing processes, such as etching, result in weak adhesion of micro-LED mesas to substrates, leading to peeling issues and damage to sidewalls, affecting the optical and electrical properties of the LED structure, especially as mesa sizes decrease.
Innovation Solution
The use of an ion-implanted isolation material to divide the second doping type semiconductor layer into individual LED mesas without etching the epitaxy layer, enhancing adhesion and reducing physical damage by forming a continuous bonding area and electrically isolating the mesas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching process is used to electrically isolate individual micro-LEDs, then electrical isolation is achieved, but adhesion of micro-LED mesas to substrate becomes weak causing peeling
Solution Approach 1:
The patent introduces an isolation layer as an intermediary substance between the micro-LED mesas and the substrate. This isolation layer serves dual functions: it provides electrical isolation between adjacent LEDs while simultaneously acting as an adhesion promoter that strengthens the bond between the mesas and substrate, preventing peeling issues
Solution Approach 2:
The patent changes the physical and chemical parameters of the interface between mesas and substrate by introducing the isolation layer. This layer modifies the surface properties and adhesion characteristics, enabling strong bonding while maintaining electrical isolation. The isolation layer's specific material properties are optimized to achieve both adhesion and isolation requirements
2Reliability
If conventional etching process is used to isolate micro-LED mesas, then electrical isolation is achieved, but sidewalls of micro-LED mesas are damaged affecting optical and electrical properties
Solution Approach 1:
The patent extracts the etching step from the manufacturing process by using an isolation layer applied before mesa formation. This eliminates the harmful etching action that damages sidewalls while still achieving the desired electrical isolation between adjacent micro-LEDs through the isolation layer
Solution Approach 2:
The isolation layer is applied in advance before the mesa formation and transfer processes. This preliminary action prepares the substrate surface with isolation properties before the micro-LEDs are created and transferred, preventing sidewall damage during subsequent processing steps
3Area of moving object
If micro-LED mesas are made smaller to increase pixel density, then display resolution is improved, but adhesion problems become more significant
Solution Approach 1:
The patent changes the adhesion parameters by introducing the isolation layer, which provides consistent adhesion performance across different mesa sizes. This allows miniaturization of LEDs while maintaining reliable bonding, as the isolation layer compensates for the reduced contact area between smaller mesas and the substrate
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 approach improves the adhesion of micro-LEDs to substrates, reduces sidewall damage, and enhances the optical and electrical properties of micro-LEDs by eliminating the need for etching and allowing for better control over the isolation process.
Implementation Method 1
The second doping type semiconductor layer includes an isolation material made through implantation, and the isolation material divides the second doping type semiconductor layer into a plurality of LED mesas
Data Source
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AI summary
A LED structure includes a substrate, a bonding layer, a first doping type semiconductor layer, a multiple quantum well (MQW) layer, a second doping type semiconductor layer, a passivation layer and an electrode layer. The bonding layer is formed on the substrate, and the first doping type semiconductor layer is formed on the bonding layer. The MQW layer is formed on the first doping type semiconductor layer, and the second doping type semiconductor layer is formed on the MQW layer. The second doping type semiconductor layer includes an isolation material made through implantation, and the passivation layer is formed on the second doping type semiconductor layer. The electrode layer is formed on the passivation layer in contact with a portion of the second doping type semiconductor layer through a first opening on the passivation layer.