Micro-LED Edge Isolation for Leakage Current Reduction
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Solution Overview
Problem
Micro-light-emitting diodes (micro-LEDs) face challenges in maintaining efficiency and reducing non-radiative recombination and leakage currents due to charge carrier spreading to the side surfaces, which limits their miniaturization and performance.
Innovation Solution
The implementation of a micro-LED structure that includes a first and second type semiconductor layer, an edge isolation structure, and electrodes, where the edge isolation structure is used to isolate the edge of the micro-LED, reducing charge carrier spreading to the side surfaces and enhancing current flow through specific passages, thereby minimizing non-radiative recombination and leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If micro-LED size is reduced for miniaturization, then device size decreases, but charge carrier spreading to side surfaces increases causing non-radiative recombination and efficiency loss
Solution Approach 1:
The patent extracts and removes the harmful side surfaces from the micro-LED structure by implementing edge isolation. The active layer is detached from the substrate and side surfaces are removed or isolated, preventing charge carrier spreading to side surfaces which causes non-radiative recombination. This extraction of harmful elements resolves the contradiction by maintaining miniaturization while eliminating the associated energy loss.
Solution Approach 2:
The patent introduces an edge isolation structure as an intermediary between the active layer and the environment. This isolation structure prevents direct interaction between charge carriers and side surfaces, thereby blocking the pathway for non-radiative recombination. The intermediary protects the charge carriers while maintaining the compact micro-LED structure.
2Volume of moving object
If micro-LED size is reduced for miniaturization, then device size decreases, but leakage currents increase due to charge carrier spreading
Solution Approach 1:
The patent extracts and removes the side surfaces that generate leakage currents. By detaching the active layer from the substrate and removing or isolating side surfaces, the pathways for leakage current are eliminated. This extraction resolves the contradiction by maintaining small device size while eliminating leakage current generation.
Solution Approach 2:
The edge isolation structure serves as an intermediary that blocks charge carrier spreading to side surfaces. This isolation prevents the formation of leakage current pathways while maintaining the miniaturized structure, thereby resolving the contradiction between small size and leakage current reduction.
3Loss of energy
If edge isolation structure is implemented to reduce charge carrier spreading, then efficiency increases, but device structure complexity increases
Solution Approach 1:
The patent segments the micro-LED structure into distinct components: the active layer, substrate, and edge isolation structure. This segmentation allows independent optimization of each component and simplifies the overall design. The edge isolation is implemented as a separate element that can be added without fundamentally redesigning the entire device, thereby reducing the perceived complexity while maintaining efficiency improvements.
Solution Approach 2:
The edge isolation structure applies a localized solution only at the critical edge regions where charge carrier spreading occurs. Rather than modifying the entire device structure, the isolation is concentrated at specific locations where it is most needed. This localized approach improves efficiency without requiring complex changes throughout the entire device.
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 configuration increases the efficiency of micro-LEDs by reducing non-radiative recombination and leakage currents, allowing for further miniaturization and improved performance by ensuring that charge carriers primarily flow through the active layer, thus enhancing light emission efficiency.
Implementation Method 1
In an LED, when electrons and holes recombine across the semiconductor gap, the recombination energy is emitted in the form of photons and generates light. This recombination mechanism is the so-called radiative recombination.
Implementation Method 2
The first edge isolation structure is at least partially located on the part of the first type semiconductor layer. The first edge isolation structure is used to isolate the edge of the micro-LED, reducing charge carrier spreading to the side surfaces
Implementation Method 3
The first electrode and the second electrode are configured to forward bias the first p-n junction while reverse bias the second p-n junction
Data Source
AI summary
A micro-light-emitting diode (micro-LED) includes a first type semiconductor layer, a second type semiconductor layer, a first edge isolation structure, a first electrode, and a second electrode. The second type semiconductor layer and the first edge isolation structure are joined with the first type semiconductor layer. The first electrode is electrically coupled with the first type semiconductor layer. At least a part of a vertical projection of an edge of the first type semiconductor layer on the first electrode overlaps with the first electrode. The first edge isolation structure is at least partially located on the part of the first type semiconductor layer. The second electrode is electrically coupled with the second type semiconductor layer.