3D GaN LED Growth Sequence for Carrier Leak Suppression
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Solution Overview
Problem
Existing light-emitting diodes (LEDs) based on nanowires face issues with parasitic growth and carrier leaks, leading to deteriorated performance due to poorly controlled mixed architectures during manufacturing.
Innovation Solution
A method for manufacturing GaN-based LEDs with a mixed axial and radial 3D structure, where axial growth steps are alternated with radial growth steps to form carrier blocking layers, optimizing the LED architecture and reducing carrier leaks by intentionally forming a radial shell around axial portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If axial growth is used to form LED portions, then the LED architecture is well-defined with proper layer stacking, but parasitic growth occurs forming partial shells that cause carrier leaks
Solution Approach 1:
The growth process is segmented into distinct axial growth steps and radial growth steps. Axial growth forms the vertical stack of LED portions, while radial growth forms complete carrier blocking shells. This segmentation allows each growth mode to perform its specialized function without the parasitic effects that occur when mixed unintentionally.
Solution Approach 2:
A complete radial carrier blocking shell is formed preliminarily around the active region before final axial growth of outer portions. This preliminary radial shell prevents carrier leaks that would otherwise occur during subsequent axial growth steps, ensuring reliability while maintaining architectural precision.
2Reliability
If radial growth is used to form carrier blocking layers, then carrier leaks are reduced, but the architectural control and layer stacking precision deteriorate
Solution Approach 1:
The growth process is segmented into distinct axial growth steps and radial growth steps. Axial growth forms the vertical stack of LED portions, while radial growth forms complete carrier blocking shells. This segmentation allows each growth mode to perform its specialized function without the parasitic effects that occur when mixed unintentionally.
3Manufacturing precision
If mixed axial and radial growth steps are implemented, then optimal LED architecture is achieved, but manufacturing process complexity increases
Solution Approach 1:
The manufacturing process uses periodic alternation between axial growth steps and radial growth steps. Each axial step builds vertical structure, followed by a radial step that forms carrier blocking shells. This periodic pattern simplifies control compared to continuous mixed growth, as each step type has standardized parameters and objectives.
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 enhances the internal quantum efficiency and overall efficiency of the LEDs by improving crystalline quality and radial coverage, effectively limiting and suppressing carrier leaks.
Implementation Method 1
Such an axial LED may typically be made by molecular beam epitaxy MBE (acronym for Molecular Beam Epitaxy). In the case of a GaN-based LED, the molecular flow of the nitrogen precursor is primarily oriented according to the longitudinal direction z
Implementation Method 2
the method further comprises at least one formation by radial growth of at least one so-called radial portion, said at least one radial portion comprising: a carrier blocking layer extending in contact with at least one of the base and the top of the active region, and completely covering walls of at least one axial portion
Data Source
AI summary
A method for manufacturing a 3D LED including the next formations of the axial portions, according to (z), a lower portion, an active region bearing on the lower portion, an upper portion bearing on the active region, the method further includes forming a radial portion, including a carrier blocking layer extending in contact with the base or with the top of the active region, and completely covering the walls of an axial portion, the radial formation being interposed between two consecutive axial formations.