μ-LED Concentric Intermixing Structure for Edge Recombination Loss
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Solution Overview
Problem
Current μ-LED technologies face challenges in achieving high radiative recombination efficiency and longevity due to defects at the edge regions of the active layer, which affect luminosity and current handling capabilities, especially in automotive and augmented reality applications where high luminosity and contrast are required.
Innovation Solution
The implementation of a semiconductor structure with a patterned mask to selectively introduce dopants for quantum well intermixing, followed by an annealing process to reduce interstitial atoms and prevent non-radiative recombination, combined with a concentric arrangement of quantum well intermixing regions to limit charge carrier movement and edge defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional μ-LED structures are used, then manufacturing is simpler, but radiative recombination efficiency is reduced due to edge defects
Solution Approach 1:
The patent applies local quality by creating concentric zones with different doping concentrations within the semiconductor structure. The inner region has a first doping concentration while the outer region has a second doping concentration, allowing different areas to serve different functions: the inner region optimizes for radiative recombination while the outer region manages edge defects and carrier injection, thereby improving overall efficiency without requiring a completely new structure
Solution Approach 2:
The semiconductor structure is segmented into multiple concentric regions with distinct doping profiles. This segmentation allows independent optimization of each region's properties to address specific problems: the inner region handles high-current-density radiative recombination while outer regions manage edge effects and non-radiative recombination, resolving the contradiction between efficiency and structural simplicity
2Illumination intensity
If high current densities are applied to achieve high luminosity, then brightness is improved, but non-radiative recombination increases due to edge defects
Solution Approach 1:
By implementing spatially varying doping concentrations in concentric zones, the patent creates regions optimized for different current densities. The inner region with appropriate doping handles high current densities efficiently for luminosity, while outer regions with different doping concentrations manage edge effects that cause non-radiative recombination, allowing high brightness without proportional energy loss
Solution Approach 2:
The patent converts the potentially harmful edge effects into a benefit by deliberately designing the outer regions with specific doping concentrations that manage carrier flow at edges. Instead of edge defects causing non-radiative recombination, the structured doping profile directs carriers through controlled paths that reduce edge-related losses while maintaining high luminosity
3Productivity
If dopant concentration is increased to improve carrier injection, then current handling is improved, but non-radiative recombination increases due to interstitial atoms
Solution Approach 1:
The patent applies local quality by using different doping concentrations in different spatial zones. The inner region uses a doping concentration optimized for carrier injection and current handling, while the outer region uses a different concentration to minimize interstitial atom formation and non-radiative recombination, allowing high productivity without sacrificing reliability
Solution Approach 2:
The doping profile is segmented into multiple zones with distinct concentrations. This segmentation allows the inner region to maximize current handling capability while outer regions are optimized to reduce non-radiative recombination from interstitial atoms, resolving the contradiction between productivity and reliability
4Reliability
If quantum well intermixing is used to reduce edge defects, then radiative efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The quantum well intermixing is applied locally in specific concentric zones rather than uniformly throughout the structure. This localized approach reduces edge defects in critical regions while minimizing the overall manufacturing complexity by limiting the intermixing process to where it is most needed, balancing reliability improvement with ease of manufacture
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 significantly enhances the low current efficiency and extends the lifespan of μ-LEDs by reducing non-radiative recombination and maintaining high luminosity across varying current densities, suitable for demanding applications like automotive and augmented reality displays.
Implementation Method 1
selectively introduce dopants for quantum well intermixing
Implementation Method 2
high radiative recombination efficiency
Implementation Method 3
prevent non-radiative recombination
Implementation Method 4
followed by an annealing process to reduce interstitial atoms
Implementation Method 5
concentric arrangement of quantum well intermixing regions to limit charge carrier movement
Data Source
AI summary
The invention relates to various aspects of a μ-LED or a μ-LED array for augmented reality or lighting applications, in particular in the automotive field. The μ-LED is characterized by particularly small dimensions in the range of a few μm.