μ-LED Active Layer Structure for Edge Defect Recombination Control
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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 areas of the active layer, which affect luminosity and current density handling, especially in small dimensions relevant for automotive and augmented reality applications.
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 enhance the stability of the active layer, combined with a concentric arrangement of regions to limit charge carrier movement and reduce non-radiative recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If μ-LED dimensions are reduced for automotive and augmented reality applications, then device size and integration density are improved, but radiative recombination efficiency and longevity deteriorate due to edge defects
Solution Approach 1:
The patent applies local quality by creating distinct regions with different dopant concentrations and compositions within the μ-LED structure. Specifically, the active layer contains a first region with first dopant atoms and a second region with second dopant atoms, allowing different local properties to address edge defects while maintaining overall device functionality. This regional differentiation enables targeted improvement of radiative recombination efficiency in defect-prone edge areas.
Solution Approach 2:
The patent implements preliminary action through the annealing process performed before final device operation. The annealing step pre-treats the μ-LED structure by reducing interstitial atoms and stabilizing the dopant distribution, thereby preventing future degradation and extending device lifespan before the μ-LED enters service in automotive or augmented reality applications.
2Use of energy by moving object
If dopants are introduced to improve radiative recombination, then light generation efficiency is improved, but non-radiative recombination increases due to interstitial atoms
Solution Approach 1:
The patent converts the harmful effect of dopant-induced interstitial atoms into a beneficial outcome through the annealing process. The annealing step transforms the structure by reducing interstitial atoms and stabilizing dopant positions, thereby converting potential energy loss pathways into efficient radiative recombination channels. This approach maintains high light generation efficiency while minimizing non-radiative recombination losses.
Solution Approach 2:
The patent employs parameter changes by modifying the thermal and compositional parameters during manufacturing. The annealing process changes temperature and time parameters to optimize dopant distribution and reduce defects. Additionally, the controlled introduction of different dopant types and concentrations allows tuning of recombination characteristics to maximize radiative efficiency while minimizing non-radiative losses.
3Duration of action of stationary object
If annealing process is applied to reduce interstitial atoms, then device stability and lifespan are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the annealing step with existing manufacturing工艺流程, integrating it into the standard μ-LED fabrication sequence. By combining the annealing process with dopant introduction and structural formation steps, the patent reduces overall manufacturing complexity while still achieving the desired reduction in interstitial atoms and improvement in device lifespan. This integrated approach avoids adding separate, standalone annealing equipment or processes.
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 improves the low current efficiency and extends the lifespan of μ-LEDs by minimizing degradation, ensuring high luminosity and efficient light generation across varying current densities, essential for automotive and augmented reality applications.
Implementation Method 1
selectively introduce dopants for quantum well intermixing
Implementation Method 2
followed by an annealing process to reduce interstitial atoms
Implementation Method 3
annealing process to reduce interstitial atoms
Implementation Method 4
achieving high radiative recombination efficiency
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.