Protrusion Recess Structure in Semiconductor Light Emitting Device
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Solution Overview
Problem
Conventional semiconductor light emitting devices with protrusion and recess structures face challenges in improving light extraction efficiency due to complex manufacturing processes and low yield, as well as high ohmic contact resistance and operating voltage.
Innovation Solution
A semiconductor light emitting device with a protrusion and recess structure is designed, where the structure is formed between a lower clad layer and a second electrode, using a simple manufacturing process involving etching to enhance light scattering and extraction efficiency, with specific materials and dimensions for the clad layers and electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a protrusion and recess structure is formed on the sapphire substrate to improve light extraction efficiency, then light scattering is enhanced, but the manufacturing process becomes complicated and yield decreases
Solution Approach 1:
Instead of forming the protrusion and recess structure on the sapphire substrate (conventional approach), the patent inverts the approach by forming the structure on the lower clad layer that is in contact with the sapphire substrate. This allows the light scattering function to be achieved while simplifying the manufacturing process and avoiding the complexity of forming structures directly on the substrate.
Solution Approach 2:
The protrusion and recess structure is formed on the lower clad layer before final electrode formation. This preliminary action allows the light scattering structure to be established early in the manufacturing process, simplifying subsequent steps and improving overall yield while maintaining light extraction efficiency.
2Illumination intensity
If the protrusion and recess structure is formed on the p-GaN clad layer to scatter light, then light extraction is improved, but ohmic contact resistance increases and operating voltage rises
Solution Approach 1:
Instead of forming the protrusion and recess structure on the p-GaN clad layer (conventional approach), the patent inverts the approach by forming the structure on the lower clad layer. This inversion separates the light scattering function from the electrode contact region, allowing light to be scattered effectively while maintaining low ohmic contact resistance at the electrode interface.
Solution Approach 2:
The patent segments the device into distinct functional regions: the lower clad layer contains the protrusion and recess structure for light scattering, while the p-GaN clad layer and electrode regions maintain flat surfaces for optimal electrical contact. This segmentation allows each layer to perform its specific function without compromising the other.
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 proposed design significantly improves light extraction efficiency and simplifies the manufacturing process, achieving higher light output power while reducing operating voltage and ohmic contact resistance.
Implementation Method 1
the light generated from the active layer can be scattered toward the sapphire substrate rather than being trapped
Data Source
AI summary
The semiconductor light emitting device having a protrusion and recess structure includes: a lower clad layer disposed on a substrate; an active layer formed on one portion of a top surface of the lower clad layer; an upper clad layer formed on the active layer; a first electrode formed on the upper clad layer; and a second electrode that is formed on a protrusion and recess structural pattern region formed on a portion of the top surface of the lower clad layer not occupied by the active layer.