Patterned LED Substrate for Low-Dislocation Epitaxial Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED technologies face challenges due to high dislocation density in epitaxial layers grown on heterogeneous substrates, leading to reduced internal quantum efficiency and brightness, as current substrate patterning techniques have limitations in reducing the epitaxial region size and can result in adverse effects during epitaxial layer formation.
Innovation Solution
A patterned substrate with periodically arranged structures, where each structure includes a first portion and a second portion, with adjacent structures spaced no more than 0.1 μm apart, is used to reduce dislocation density and improve epitaxial layer quality by incorporating nucleation-inhibiting materials and angled surfaces that enhance light scattering and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the epitaxial region is made smaller to reduce dislocation density, then the internal quantum efficiency is improved, but the difficulty of forming high-quality epitaxial layer increases
Solution Approach 1:
The substrate surface is segmented into multiple small epitaxial regions separated by non-epitaxial regions. Each epitaxial region has a size of 1-10 μm, creating numerous independent growth sites that collectively provide sufficient area for high-quality epitaxial layer formation while maintaining low dislocation density in each region.
Solution Approach 2:
Different regions of the substrate are assigned different functions: epitaxial regions (1-10 μm) are optimized for low dislocation density and high crystal quality, while non-epitaxial regions serve as spacing elements and stress relief zones. This local differentiation allows the epitaxial regions to be small enough for high quality while the overall substrate provides sufficient total area.
2Manufacturing precision
If the epitaxial region is made too small, then the dislocation density is reduced, but difficulties are encountered during epitaxial layer formation
Solution Approach 1:
The substrate is divided into multiple epitaxial regions each 1-10 μm in size, which is small enough to limit dislocation propagation but large enough to allow proper nucleation and growth of high-quality epitaxial material. The segmentation creates many independent growth sites that collectively provide sufficient area.
Solution Approach 2:
The patent specifies precise parameter ranges for epitaxial region size (1-10 μm) and spacing (1-20 μm) to optimize the balance between dislocation density reduction and epitaxial layer formation quality. These parameter changes ensure each region is small enough for low dislocation density while maintaining adequate size for high-quality growth.
3Reliability
If conventional substrate patterning is used to reduce epitaxial region size, then dislocation density is reduced, but the reduction is limited and brightness is not sufficiently improved
Solution Approach 1:
The substrate surface is segmented into numerous small epitaxial regions (1-10 μm) separated by non-epitaxial regions, creating a high density of independent growth sites. This segmentation approach achieves much greater dislocation density reduction compared to conventional single large epitaxial regions, directly improving LED brightness.
Solution Approach 2:
The patent transitions from conventional two-dimensional epitaxial growth to a patterned approach where epitaxial regions are distributed across the substrate surface in a controlled pattern. This dimensional organization allows simultaneous optimization of multiple parameters: small region size for low dislocation density, adequate spacing for stress relief, and sufficient total area for high brightness.
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 approach significantly reduces dislocation density, improves epitaxial quality, and increases light-emission efficiency, resulting in enhanced brightness and internal quantum efficiency of LEDs.
Implementation Method 1
incorporating nucleation-inhibiting materials and angled surfaces that enhance light scattering and reflection
Implementation Method 2
incorporating nucleation-inhibiting materials and angled surfaces that enhance light scattering and reflection
Implementation Method 3
substrate patterning has been developed in order to suppress dislocation glide and internal dislocation of the epitaxial layer
Implementation Method 4
The epitaxial layer is formed by epitaxially growing an LED material on a surface of the patterned substrate
Data Source
AI summary
A patterned substrate includes a substrate body having a surface and a plurality of patterned structures periodically arranged on the surface of the substrate body, where each of the patterned structures includes a first portion formed on the surface of the substrate body, and a second portion formed on the first portion, and where any two adjacent ones of the patterned structures are spaced apart from one another by a minimum distance of not greater than 0.1 μm. A light-emitting diode includes the patterned substrate and a semiconductor epitaxial structure formed thereon. A process for preparing the patterned substrate and a process for preparing the light-emitting diode are also disclosed.