Micro LED Mesa Structure With Ion Implantation Fence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional micro LEDs face challenges such as reduced light extraction efficiency due to spaces between adjacent mesas, nonradiative recombination at mesa sidewalls, and cross-talk between adjacent LEDs, which affect their performance and efficiency.
Innovation Solution
The micro LED structure incorporates a mesa structure, a trench, and an ion implantation fence with a higher electrical resistance than the mesa structure, which reduces nonradiative recombination and allows for a decreased space between adjacent mesas, enhancing light extraction efficiency and integration level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the LED chip size is reduced to achieve high-resolution displays, then the resolution is improved, but the current carrying capacity decreases leading to insufficient brightness
Solution Approach 1:
The LED chip structure is segmented into multiple functional regions including InGaN light-emitting layers, AlGaN electron blocking layers, and p-type GaN cap layers. This segmentation allows optimization of current distribution and light emission efficiency in each region, enabling high brightness despite small chip size
Solution Approach 2:
Different layers are designed with specific local properties: the AlGaN electron blocking layer has high aluminum content (20-40%) to block electrons and enhance light emission in specific regions, while the p-type GaN cap layer has optimized thickness (50-200nm) and doping concentration to improve hole injection and current distribution locally
2Ease of manufacture
If conventional LED structures are used in small chip sizes, then manufacturing is simpler, but current distribution becomes uneven causing quality issues
Solution Approach 1:
The p-type GaN cap layer is formed preliminarily before the LED chip is mounted on the substrate. This preliminary formation ensures uniform current distribution is built into the chip structure itself, preventing current concentration issues that would otherwise require complex post-processing or substrate designs
Solution Approach 2:
The doping concentration and thickness of the p-type GaN cap layer are precisely controlled (50-200nm thickness, specific doping levels) to optimize hole injection and current distribution. These parameter changes enable uniform current flow across the small chip area without complicating the manufacturing process
3Measurement precision
If the chip area is reduced for high resolution, then display density is improved, but heat dissipation becomes insufficient
Solution Approach 1:
The p-type GaN cap layer serves as an intermediary between the active light-emitting regions and the substrate contact. It facilitates efficient heat conduction from the small chip area to the substrate while maintaining uniform current distribution, effectively managing heat dissipation in high-density display configurations
Solution Approach 2:
The LED chip uses composite material structure with multiple semiconductor layers (InGaN, AlGaN, GaN) each with different thermal and electrical properties. This composite structure optimizes both light emission and heat dissipation pathways, enabling small chip size with adequate thermal management
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 configuration improves the active light emitting efficiency and increases the integration level of micro LEDs, leading to enhanced image quality and performance compared to conventional micro LEDs.
Implementation Method 1
a ion implantation fence separated from the mesa structure, the trench extending up through the first type semiconductor layer and extending up into at least part of the first type cap layer; and the ion implantation fence is formed around the trench
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 2~3
AI summary
A micro LED includes a first type semiconductor layer; and a light emitting layer formed on the first type semiconductor layer; a first type cap layer formed at a bottom surface of the light emitting layer and between the first type semiconductor layer and the light emitting layer; wherein the first type semiconductor layer includes a mesa structure, a trench, and a ion implantation fence separated from the mesa structure, the trench extending up through the first type semiconductor layer and extending up into at least part of the first type cap layer; and the ion implantation fence is formed around the trench and the trench is formed around the mesa structure; wherein an electrical resistance of the ion implantation fence is higher than an electrical resistance of the mesa structure .