Micro-LED Structure With Ion-Implanted Isolation for Stronger Adhesion
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Solution Overview
Problem
Conventional etching processes used in manufacturing micro-LEDs result in weak adhesion of micro-LED mesas to substrates, leading to peeling issues and damage to sidewalls, which affects the optical and electrical properties of the LED structure, especially as mesas become smaller.
Innovation Solution
The implementation of an ion-implanted isolation material within the semiconductor layers to electrically isolate micro-LED units without etching the epitaxy layer, enhancing adhesion and reducing physical damage by forming a continuous bonding area and using ion implantation to create highly resistive regions for improved electrical confinement.
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 and maintains mechanical adhesion to the substrate, preventing the peeling issue caused by conventional etching processes that completely remove the epitaxy layer.
Solution Approach 2:
The patent changes the parameter of the epitaxy layer by controlling the etching depth to stop before completely removing the layer. By adjusting the etching depth parameter and introducing the isolation layer, the system achieves both electrical isolation and maintained adhesion, resolving the contradiction between isolation effectiveness and structural integrity.
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 isolation layer acts as a protective intermediary during the etching process. It is positioned between the etching environment and the micro-LED sidewalls, preventing direct contact and damage to the sidewalls while still allowing the etching process to achieve electrical isolation between adjacent LEDs.
Solution Approach 2:
The patent applies beforehand cushioning by introducing the isolation layer prior to the etching process. This layer provides a protective buffer that cushions the sidewalls from the harmful effects of the etching process, preventing damage while enabling the necessary electrical isolation.
3Productivity
If micro-LED mesas are made smaller to increase display resolution, then pixel density is improved, but adhesion becomes even weaker making peeling more significant
Solution Approach 1:
The isolation layer serves as a critical intermediary that becomes increasingly important as mesa size decreases. For smaller mesas with reduced adhesion area, the isolation layer provides additional anchoring to the substrate, compensating for the reduced adhesion strength and preventing peeling even as pixel density increases.
Solution Approach 2:
The patent applies preliminary action by forming the isolation layer before transferring the micro-LED mesas to the final substrate. This preliminary preparation ensures that even very small mesas have adequate adhesion support from the outset, enabling high pixel density displays without suffering from peeling issues.
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 strengthens 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 processes, thereby improving the manufacturing process and performance of micro-LED arrays.
Implementation Method 1
The second doping type semiconductor layer includes an isolation material made through implantation
Data Source
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.