Semiconductor Light Emitting Device Capping Layer Dopant Diffusion
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Solution Overview
Problem
The degradation of crystal quality and performance in semiconductor light emitting devices due to p-type dopant diffusion into the active layer, which affects the emission wavelength and efficiency.
Innovation Solution
A semiconductor light emitting device with a capping layer that blocks p-type dopant diffusion, comprising a material with a smaller lattice constant and higher energy band gap than the quantum barrier layer, positioned between the active layer and the electron blocking layer, to enhance doping efficiency and minimize crystal quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p-type semiconductor layer is grown directly on the active layer, then hole injection efficiency is improved, but p-type dopant diffuses into the active layer degrading crystal quality
Solution Approach 1:
An undoped capping layer is inserted between the p-type semiconductor layer and the active layer. This intermediary layer physically blocks the diffusion of p-type dopants into the active layer while still allowing the p-type layer to provide holes to the active layer for efficient hole injection.
Solution Approach 2:
The structure is segmented by dividing the direct contact between the p-type semiconductor layer and active layer into two separate regions: the first region (capping layer) that blocks dopant diffusion and the second region (p-type semiconductor layer) that provides holes. This segmentation resolves the contradiction by separating the two conflicting functions.
2Manufacturing precision
If the capping layer is made of material with smaller lattice constant and higher energy band gap, then dopant diffusion is blocked, but device complexity increases
Solution Approach 1:
The capping layer uses materials with specific parameter changes - smaller lattice constant and higher energy band gap compared to the quantum barrier layer. These parameter changes enable effective dopant diffusion blocking while maintaining compatibility with the existing quantum well structure.
Solution Approach 2:
The device employs a composite structure combining the capping layer made of specific materials (such as AlGaN with appropriate composition) with the existing quantum well and p-type layer structures. This composite approach achieves dopant blocking functionality while integrating with the overall device architecture.
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 capping layer effectively prevents p-type dopant diffusion, maintaining crystal quality and enhancing hole injection efficiency, leading to improved luminescent and electrical properties.
Implementation Method 1
a capping layer disposed between the active layer and the electron blocking layer and blocking a p-type dopant element from being injected into the active layer
Implementation Method 2
an active layer disposed between the n-type and p-type semiconductor layers and having a structure in which single or a plurality of quantum well layers and quantum barrier layers are alternately disposed
Implementation Method 3
an electron blocking layer disposed between the active layer and the p-type semiconductor layer
Data Source
AI summary
A semiconductor light emitting device includes first conductivity type and second conductivity type semiconductor layers, an active layer disposed between the semiconductor layers and having a structure in which one or more quantum well layers and one or more quantum barrier layers are alternately disposed An electron blocking layer is disposed between the active layer and the second conductivity type semiconductor layer. A capping layer is disposed between the active layer and the electron blocking layer and blocking a dopant element from being injected into the active layer from the second conductivity type semiconductor layer.