μ-LED Mirror-Passivation Layout for Side Emission Control
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Solution Overview
Problem
Optoelectronic components, particularly μ-LEDs, face challenges with side emission due to their small dimensions, leading to reduced quantum efficiency and increased optical crosstalk, which complicates the creation of a mirror layer with high reflectivity.
Innovation Solution
A spatial separation of the electrical passivation and optical reflector functions allows for independent optimization of these components. The epitaxial layer sequence includes a functional inner region with semiconductor layers surrounded by a dielectric passivation layer, and a mirror layer is formed separately to optimize reflectivity without compromising passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a metallic mirror layer is applied to cover the side walls of μ-LEDs, then side emission can be directed towards the light-emitting surface, but the reflectivity of the mirror layer is heavily dependent on the properties of the side surfaces, making it difficult to achieve high reflectivity
Solution Approach 1:
The invention separates the side wall coverage into two distinct functional segments: a dielectric passivation layer applied directly to the side walls for electrical isolation, and a metallic mirror layer applied to the horizontal surfaces for light reflection. This segmentation allows each layer to be optimized for its specific function without the compromises required when combining both functions in a single layer.
Solution Approach 2:
The invention extracts the light reflection function from the side wall coverage structure. Instead of relying on the side walls themselves to provide both passivation and reflection, the reflection function is extracted and implemented through a separate mirror layer on horizontal surfaces, while the side walls are dedicated solely to passivation.
2Loss of energy
If measures are taken to improve quantum efficiency in the active area, then light generation is improved, but these measures complicate the creation of a mirror layer with the highest possible reflectivity
Solution Approach 1:
The invention segments the device into functionally distinct regions: the active area with its quantum efficiency optimization measures, and the mirror layer region with its reflectivity optimization measures. The dielectric passivation layer acts as a boundary that separates these two regions, allowing independent optimization of each without interference.
Solution Approach 2:
The invention applies different material properties and structural characteristics to different local regions: the active area receives treatments optimized for light generation (such as specific doping profiles and layer structures), while the mirror layer region receives treatments optimized for light reflection (such as metallic coatings and flat horizontal surfaces).
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 enables efficient utilization of side emission, improves quantum efficiency, and reduces optical crosstalk by allowing for optimized processing and design of both the passivation and mirror layers independently.
Implementation Method 1
Semiconductor layers configured to generate light are arranged between the first electrical contact and the second electrical contact
Implementation Method 2
a metallic mirror layer after electrical passivation, which serves as a reflector and directs the light emitted to the side towards a light-emitting surface
Data Source
AI summary
In an embodiment an optoelectronic component with an epitaxial layer sequence comprises a functional inner region having a first electrical contact and a second electrical contact opposite the first electrical contact, as well as semiconductor layers arranged between the first electrical contact and the second electrical contact configured to generate light. The semiconductor layers comprise a base area that increases towards the second electrical contact. A dielectric passivation layer is arranged on the side walls of the semiconductor layers. A mirror layer surrounds the passivation layer at a distance thereby forming a gap. The second electrical contact and a plane of the gap surrounding the second electrical contact form a common light-emitting surface.