Micro LED Regrown Plug Structure for Uniform Carrier Injection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Micro LEDs face reduced internal quantum efficiency due to surface defect states at sidewalls, leading to nonradiative recombination of holes and electrons, which is exacerbated by strong quantum confined stark effect and high heterojunction barriers in materials like GaN/InGaN, resulting in higher operational voltage requirements.
Innovation Solution
The implementation of regrown semiconductor layers to form plug structures that decouple sidewall injection from etched pillar sidewalls, allowing for increased carrier injection into active layers by selecting specific crystal plane facets for cavity and plug regrowth, thereby reducing voltage requirements and enhancing uniformity of carrier injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If micro LED dimensions are reduced, then device size is improved, but surface defect states at sidewalls increase causing nonradiative recombination and reducing internal quantum efficiency
Solution Approach 1:
A regrown semiconductor layer is introduced as an intermediary structure between the etched pillar sidewalls and the active layer. This regrown layer acts as a mediator that provides a defect-free pathway for carrier injection, separating the harmful etched sidewall surfaces from the active region where radiative recombination occurs.
Solution Approach 2:
The sidewall injection function is segmented from the pillar sidewall structure. Instead of relying on the etched pillar sidewalls for carrier injection, the patent creates separate regrown plug portions that are laterally offset from the pillar sidewalls, dividing the injection pathway from the structural support function.
2Reliability
If diffusion or regrowth techniques are used to passivate micro LED sidewalls, then internal quantum efficiency is improved, but device complexity increases
Solution Approach 1:
The regrown semiconductor layer is formed in advance during the LED fabrication process, before final device assembly. By performing the regrowth operation as a preliminary step, the patent integrates sidewall passivation into the existing manufacturing flow without requiring separate post-processing steps.
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 increases sidewall carrier injection, reduces operational voltage, and improves the internal quantum efficiency of micro LEDs by ensuring uniform carrier injection across all quantum well layers, mitigating the effects of strong quantum confined stark effect and high heterojunction barriers.
Implementation Method 1
selecting specific crystal plane facets for cavity and plug regrowth
Implementation Method 2
sidewall injection through the regrown plug portions into the active region can be decoupled from etched pillar sidewall surfaces
Implementation Method 3
passivate the micro LED sidewalls using techniques such as diffusion or regrowth
Data Source
AI summary
Light emitting diodes with regrown semiconductor layers and methods of manufacture are described. In an embodiment, a light emitting diode includes a base structure including a first cladding layer and a pillar structure protruding from the base layer. The pillar structure includes a mesa structure and a second cladding layer that includes a plug portion that is laterally adjacent to a plurality of quantum well layers of the mesa structure.