Nitride Semiconductor Light-Emitting Element With Concave N-Electrode
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Solution Overview
Problem
Existing light-emitting elements with negative electrodes on the outer periphery have limited current flow and high drive voltage due to restricted electric current pathways, which hinders efficient operation.
Innovation Solution
A light-emitting element with a semiconductor laminated structure featuring a concave portion on the n-type semiconductor layer and electrodes extending in the depth direction, allowing for improved ohmic contact and reduced resistance, enabling broader current flow and lower drive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If negative electrodes are arranged on the outer peripheral side of the element, then the structure is simplified and easier to manufacture, but electric current flows only in a portion of the negative electrode and the drive voltage remains high
Solution Approach 1:
The patent transitions from a two-dimensional surface arrangement of electrodes to a three-dimensional structure by forming a concave portion in the n-type contact layer and extending the n-electrode vertically into this concave portion. This dimensional change increases the contact area between the electrode and semiconductor layer, reducing resistance and enabling broader current flow paths, thereby reducing drive voltage while maintaining manufacturing simplicity.
Solution Approach 2:
The n-electrode is nested within the concave portion formed in the n-type contact layer, creating a recessed electrode structure. This nesting approach increases the effective contact area between the electrode and the semiconductor layer without increasing the planar footprint, allowing for reduced resistance and improved current distribution while maintaining a compact device structure.
2Reliability
If an irregularity is formed at the interface between the negative electrode and the n-type contact layer, then the resistance is reduced, but the current flow is still limited to specific regions
Solution Approach 1:
The patent segments the contact interface by creating a concave portion in the n-type contact layer and forming the n-electrode within this recessed region. This segmentation of the contact area into a dedicated recessed zone enhances the electrode-semiconductor interface, reducing contact resistance while the surrounding flat areas provide additional current flow pathways, improving overall current distribution across the 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
The design significantly reduces the drive voltage and enhances light emission by allowing electrical current to flow in all directions from the n-electrode to the p-contact electrode, improving the efficiency and brightness of the light-emitting element.
Implementation Method 1
a first electrode formed on the concave portion and being in ohmic contact with the first semiconductor layer
Data Source
AI summary
A light-emitting element includes a semiconductor laminated structure including a nitride semiconductor, and formed by laminating a first semiconductor layer of a first conductivity type, a light-emitting layer and a second semiconductor layer of a second conductivity type different from the first conductivity type, the first semiconductor layer being exposed by removing a part of the second semiconductor layer and the light-emitting layer, a concave portion formed in the exposed portion of the first semiconductor layer, a first electrode formed on the concave portion and being in ohmic contact with the first semiconductor layer, and a second electrode being in ohmic contact with the second semiconductor layer and formed surrounding the first electrode.