Semiconductor Light Emitting Device Border Layer Design
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Solution Overview
Problem
Semiconductor light emitting devices face degradation in film quality due to agglomeration phenomena and point defects in quantum well layers, leading to reduced luminance and efficiency, particularly when indium (In) is incorporated at different growth temperatures, causing non-uniform composition and leakage currents.
Innovation Solution
Incorporating a border layer with a gradually reduced band gap energy and a growth blocking layer, both containing specific nitride compositions, to prevent film quality degradation by controlling In composition and reducing electronic binding forces, thereby maintaining crystallinity and luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If indium is incorporated at different growth temperatures to achieve desired composition, then the band gap energy can be adjusted, but film quality degrades due to agglomeration phenomena and point defects
Solution Approach 1:
The border layer is divided into multiple sub-layers with different indium compositions (first border layer with lower In content, second border layer with higher In content). This segmentation allows gradual adjustment of band gap energy while maintaining film quality by preventing sudden composition changes that cause agglomeration.
Solution Approach 2:
Different regions of the border layer have different indium compositions tailored to local requirements. The first border layer has lower In content near the n-type layer for stability, while the second border layer has higher In content near the active layer for band gap matching, optimizing both film quality and optical properties locally.
2Illumination intensity
If indium composition is increased to reduce band gap energy, then luminance can be improved, but agglomeration phenomena occur leading to non-uniform composition
Solution Approach 1:
The first border layer with lower indium content is grown before the second border layer with higher indium content. This preliminary action prepares the film structure to accommodate higher In content gradually, preventing agglomeration by establishing a stable gradient before introducing more indium.
Solution Approach 2:
The indium composition parameter is changed gradually across different border layers rather than abruptly. The composition transitions from lower In content in the first border layer to higher In content in the second border layer, maintaining composition uniformity while achieving the desired band gap reduction for improved luminance.
3Manufacturing precision
If growth temperature is varied to control indium incorporation, then composition can be optimized, but point defects increase reducing internal quantum efficiency
Solution Approach 1:
The growth temperature is dynamically adjusted for different border layers. Lower temperatures are used for the first border layer to minimize defects, while optimized temperatures are applied for the second border layer to achieve desired composition without excessive point defects, balancing composition control and efficiency.
4Illumination intensity
If border layer thickness is increased to improve band gap matching, then luminance increases, but growth blocking layer becomes less effective at preventing In diffusion
Solution Approach 1:
The border layer is segmented into multiple thin sub-layers rather than one thick layer. This segmentation maintains the total thickness needed for band gap matching while ensuring that the growth blocking layer remains effective at preventing indium diffusion across each thinner interface, preserving composition control.
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
The solution enhances luminance, internal quantum efficiency, and reduces droop phenomena by suppressing In agglomeration and point defects, resulting in improved light characteristics and prolonged device performance.
Implementation Method 1
the at least one border layer having a band gap energy that decreases in a direction away from the first conductivity-type semiconductor layer
Implementation Method 2
the at least one growth blocking layer having a band gap energy equal to a band gap energy of the at least one quantum barrier layer
Implementation Method 3
the active layer including at least one quantum well layer and at least one quantum barrier layer that are alternately stacked and form a multiple quantum well structure
Data Source
AI summary
A semiconductor light emitting device including a first conductivity-type semiconductor layer; a second conductivity-type semiconductor layer; an active layer interposed between the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer, the active layer including at least one quantum well layer and at least one quantum barrier layer that are alternately stacked and form a multiple quantum well structure; at least one border layer in contact with the first conductivity-type semiconductor layer and interposed between the first conductivity-type semiconductor layer and the active layer, the at least one border layer having a band gap energy that decreases in a direction away from the first conductivity-type semiconductor layer; and at least one growth blocking layer interposed between the active layer and the border layer, the at least one growth blocking layer having a band gap energy equal to a band gap energy of the at least one quantum barrier layer.