Sn Particle-Group Substrates for Low-Defect GaN Epitaxy
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Solution Overview
Problem
Micro-LEDs with sizes smaller than 100 μm face issues of high lattice defects and low light-emitting efficiency due to lattice matching problems between sapphire substrates and GaN, leading to poor anti-ESD capability.
Innovation Solution
A light-emitting semiconductor substrate with a base and dispersed particle groups made of Sn or Sn compounds, which facilitate the growth of an epitaxy structure by reducing lattice mismatch and stress, thereby improving epitaxy quality and anti-ESD capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If micro-LEDs are fabricated on sapphire substrates, then device miniaturization is achieved, but lattice matching problems cause high dislocation density and low light-emitting efficiency
Solution Approach 1:
A buffer layer comprising multiple sub-layers with gradually changing composition ratios is introduced between the sapphire substrate and the GaN epitaxy structure. The buffer layer acts as an intermediary that progressively transitions the lattice structure, reducing the abrupt lattice mismatch and dislocation density at the interface, thereby improving epitaxy quality for miniaturized micro-LEDs
Solution Approach 2:
The composition ratio of InGaN in the buffer layer is gradually changed from the first sub-layer to the second sub-layer, creating a compositional gradient. This parameter change allows progressive lattice matching, reducing dislocation density and improving the quality of the GaN epitaxy structure while maintaining micro-LED miniaturization
2Length of moving object
If micro-LEDs are reduced to smaller than 100 μm, then device miniaturization is achieved, but anti-ESD capability deteriorates
Solution Approach 1:
The buffer layer with graded InGaN composition serves as an intermediary structure that reduces lattice mismatch and dislocation density, thereby improving the overall structural integrity and reliability of miniaturized micro-LEDs, including their anti-ESD capability
Solution Approach 2:
The device employs a composite structure combining sapphire substrate, graded InGaN buffer layer with multiple sub-layers of varying composition ratios, and GaN epitaxy structure. This composite material approach allows optimization of both miniaturization and reliability properties
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 substrate design enhances the lateral growth of the epitaxy structure, reducing defects and improving light-emitting efficiency and anti-ESD capability, as demonstrated by the comparison with a structure lacking particle groups.
Implementation Method 1
high lattice defects or a high dislocation density are easily generated as a result of the lattice matching problems between the sapphire substrate and GaN
Data Source
AI summary
A light-emitting semiconductor substrate, which is applied to a light-emitting semiconductor structure, includes a base and a plurality of particle groups. The base includes an upper surface. The particle groups are on the upper surface or inside the base dispersedly, and each of the particle groups includes Sn, Sn compounds or combinations thereof.