Micro LED Current Blocking Structure for Etched Sidewall Losses
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Solution Overview
Problem
The emission efficiency of micro LEDs deteriorates as the size of the chip decreases due to sidewall etching damage, which prevents electron-hole pairs from normal bonding, leading to reduced current injection and emission efficiency.
Innovation Solution
A micro light emitting device is designed with a current blocking layer, including a porous gallium nitride layer or an air layer, that controls current flow toward the active layer, concentrating it in a damage-free central area and preventing leakage through the sidewall, thereby improving emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of micro LED chip is decreased to achieve high-resolution display, then the pixel density and resolution are improved, but the emission efficiency deteriorates due to sidewall etching damage
Solution Approach 1:
The patent applies local quality by creating a current blocking layer with different properties at different locations. The sidewall region receives a porous GaN layer with high resistance to block current, while the central region maintains normal current injection. This spatial differentiation of material properties resolves the contradiction by protecting the damaged sidewall area while preserving functionality in the healthy central area.
Solution Approach 2:
The porous GaN layer acts as an intermediary element between the damaged sidewall and the active region. It mediates the current flow by providing a high-resistance path that prevents current leakage through the damaged sidewall, thereby protecting the overall emission efficiency while allowing the device to maintain its small size for high-resolution displays.
2Device complexity
If conventional manufacturing process is used without current blocking layer, then the device structure is simple, but current leakage through damaged sidewall reduces emission efficiency
Solution Approach 1:
The patent employs porous GaN material for the current blocking layer. The porous structure provides high electrical resistance to block current leakage while maintaining a relatively thin profile. This material choice effectively improves emission efficiency by preventing current loss through the sidewall without significantly increasing device complexity.
3Ease of manufacture
If sidewall etching is performed during manufacturing, then the chip can be processed and mounted, but etching damage creates non-emission regions that reduce current injection efficiency
Solution Approach 1:
The patent converts the harmful effect of sidewall etching damage into a beneficial outcome by applying a porous GaN current blocking layer on the damaged sidewall. This layer exploits the high resistance property to prevent current leakage through the etched region, thereby transforming the previously harmful damaged area into a protected region that no longer compromises emission efficiency.
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 current blocking layer effectively reduces non-emission recombination at the sidewall, enhancing the emission efficiency of micro LEDs by ensuring current injection is concentrated in the central area, thus improving the overall performance of micro light emitting devices.
Implementation Method 1
a current blocking layer, including a porous gallium nitride layer or an air layer, that controls current flow toward the active layer
Implementation Method 2
an active layer provided on the superlattice layer
Data Source
AI summary
Provided is a micro light emitting device and a display apparatus having the micro light emitting device. The micro light emitting device includes a first-type semiconductor layer provided on a substrate, a superlattice layer provided on the first-type semiconductor layer, a current blocking layer provided on a side portion of the superlattice layer, an active layer provided on the superlattice layer and the current blocking layer, and a second-type semiconductor layer provided on the active layer.