Semiconductor UV Light Emitting Device with Protruded Active Layer
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Solution Overview
Problem
Semiconductor ultraviolet light emitting devices face challenges with poor current spreading due to high sheet resistance in AlGaN materials, leading to lower light output and increased temperature, as well as difficulties in forming ohmic contacts to reduce operating voltage.
Innovation Solution
The design includes a substrate with a first and second semiconductor layer and an active layer generating ultraviolet light by electron-hole recombination, featuring protruded parts and recesses, an insulating layer, and ohmic electrodes with irregularities on the second semiconductor layer to enhance current spreading and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If AlGaN material is used for semiconductor ultraviolet light emitting device, then ultraviolet light emission is achieved, but high sheet resistance causes poor current spreading and lower light output
Solution Approach 1:
The patent applies local quality by creating protruded parts and recesses in the semiconductor layer structure. The protruded parts concentrate current in specific regions to improve light output, while the recesses provide pathways for current spreading. This local structural variation addresses the high sheet resistance issue by optimizing current distribution in different areas of the device.
Solution Approach 2:
The patent introduces a third dimension by creating protruded parts that extend vertically from the semiconductor layer. This dimensional change allows current to spread through multiple pathways (horizontal and vertical), effectively reducing the impact of high sheet resistance and improving both current spreading and light output.
2Illumination intensity
If AlGaN material is used for semiconductor ultraviolet light emitting device, then ultraviolet light emission is achieved, but high sheet resistance leads to increased temperature
Solution Approach 1:
The recesses created in the semiconductor layer provide localized regions with improved heat dissipation. By concentrating current in protruded parts and providing thermal pathways through recesses, the structure reduces hot spots and overall operating temperature while maintaining ultraviolet light emission.
3Power
If conventional electrode structure is used, then electrical connection is achieved, but difficulty in forming ohmic contacts increases operating voltage
Solution Approach 1:
The patent performs preliminary action by pre-forming protruded parts and recesses in the semiconductor layer before electrode deposition. This pre-structured surface topology facilitates easier formation of ohmic contacts during the electrode fabrication process, reducing operating voltage without complicating manufacturing.
4Illumination intensity
If flat semiconductor layer structure is used, then simple manufacturing is achieved, but regions without ultraviolet emission reduce light emission efficiency
Solution Approach 1:
The patent applies local quality by creating protruded parts and recesses only in specific regions of the semiconductor layer. This selective structuring increases ultraviolet emission in protruded regions while keeping other areas relatively simple, thereby improving overall light emission efficiency without excessive complexity.
Solution Approach 2:
The semiconductor layer is segmented into protruded parts and recesses, creating distinct functional regions. The protruded parts are optimized for light emission, while recesses provide current spreading pathways. This segmentation improves light emission efficiency by concentrating emission in specific areas.
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 improves light emission efficiency by reducing regions without ultraviolet emission and lowering operating voltage, while minimizing damage to semiconductor layers and enhancing UV extraction.
Implementation Method 1
an active layer, which is provided on the first semiconductor layer and generates ultraviolet light by electron-hole recombination
Data Source
AI summary
Disclosed is a semiconductor light emitting device comprising: a substrate; a first semiconductor layer, which is provided on the substrate and has a first conductivity; an active layer, which is provided on the first semiconductor layer and generates ultraviolet light by electron-hole recombination; a second semiconductor layer, which is provided on the active layer and has a second conductivity different from the first conductivity; a first electrode electrically connected to the first semiconductor layer; a second electrode electrically connected to the second semiconductor layer; a second region that includes a plurality of protruded parts of the active layer and the second semiconductor layer protruded from the first semiconductor layer as seen in cross-sectional view and recesses between the protruded parts; and a first region surrounding the second region.