LED Recess Structure for Higher Light Extraction and Current Spreading
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Solution Overview
Problem
Current semiconductor devices, such as light-emitting diodes (LEDs), face challenges in maximizing light extraction efficiency due to total internal reflection and uneven current spreading, which limits their luminous intensity and radiant flux.
Innovation Solution
The optoelectronic semiconductor device incorporates a semiconductor stack with a first type and second type semiconductor structure, an active structure, and a reflective structure, featuring a recess with a gradient width and height, along with a window layer and contact structure, to enhance light reflection and extraction, thereby increasing the light-emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional flat semiconductor structure is used, then the device is simple to manufacture, but light extraction efficiency is limited due to total internal reflection
Solution Approach 1:
The patent introduces a recess structure with curved side walls into the semiconductor device. This curvature modifies the light propagation paths and reduces total internal reflection at the semiconductor-air interface, thereby improving light extraction efficiency while maintaining manufacturing feasibility through standard etching processes.
Solution Approach 2:
The invention adds vertical dimensionality by creating a recess structure that extends downward from the surface. This three-dimensional configuration increases the optical path length and creates multiple reflection opportunities, enhancing light extraction without complicating the horizontal layout or manufacturing流程.
2Device complexity
If a conventional flat semiconductor structure is used, then the device structure is simple, but current spreading is uneven
Solution Approach 1:
The curved side walls of the recess structure guide current flow more uniformly across the active region. The gradual curvature prevents current crowding at edges and promotes even distribution, improving manufacturing precision without requiring complex additional structures.
3Loss of energy
If the recess depth is increased to improve light extraction, then light extraction efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies an optimized recess depth range of 0.5-2.0 μm, which balances light extraction improvement with manufacturing feasibility. This parameter optimization ensures sufficient light extraction enhancement while remaining within the capabilities of standard semiconductor etching processes, avoiding excessive precision requirements.
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 significantly enhances light extraction efficiency and luminous intensity by reducing total reflection and improving current spreading, resulting in higher radiant flux compared to conventional devices.
Implementation Method 1
The optoelectronic semiconductor device incorporates a semiconductor stack with a first type and second type semiconductor structure, an active structure, and a reflective structure, featuring a recess with a gradient width and height, along with a window layer and contact structure, to enhance light reflection and extraction
Implementation Method 2
Under an external electrical power supply, the n-type semiconductor layer and p-type semiconductor layer provide electrons and holes respectively for the recombination in the active structure and further convert electrical energy into light
Data Source
AI summary
An optoelectronic semiconductor device includes a substrate, a first type semiconductor structure, a second type semiconductor structure, an active structure and a contact structure. The first type semiconductor structure is located on the substrate and has a first protrusion part with a first thickness and a platform part with a second thickness. The second type semiconductor structure is located on the first type semiconductor structure. The active structure is between the first type semiconductor structure and the second type semiconductor structure. The contact structure is disposed between the first type semiconductor structure and the substrate. The second thickness of the platform part is in a range of 0.01 μm to 1 μm.