AlGaN Intermediate Layer for Deep UV Light Output
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Solution Overview
Problem
Current semiconductor light emitting devices for deep ultraviolet light output face challenges in achieving optimal light output due to limitations in crystal quality and dislocation issues, which affect their efficiency.
Innovation Solution
Incorporating an intermediate layer with a silicon concentration peak between the n-type clad layer and the active layer, made of AlGaN-based semiconductor material, and forming it at a lower substrate temperature to improve wettability and inhibit dislocation propagation, thereby enhancing crystal quality and light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an intermediate layer is added between the n-type clad layer and the active layer, then the light output is improved, but the device structure becomes more complex
Solution Approach 1:
An intermediate layer is introduced between the n-type clad layer and the active layer to serve as a mediator that improves interface quality and reduces dislocation propagation. This intermediate layer acts as a buffer that enhances the overall device performance by improving the interface between dissimilar materials, thereby increasing light output despite the added structural complexity.
2Illumination intensity
If the Si concentration in the intermediate layer is increased to improve crystal quality, then the light output increases, but the manufacturing precision becomes more difficult to control
Solution Approach 1:
The Si concentration in the intermediate layer is optimized within a specific range (higher than the n-type clad layer but controlled to be appropriate for the active layer interface). By carefully adjusting this parameter, the patent achieves improved crystal quality and light output while maintaining manufacturability. The Si concentration serves as a key parameter that balances crystal quality improvement with manufacturing control.
3Manufacturing precision
If the substrate temperature during intermediate layer formation is reduced to improve wettability, then the interface quality improves, but the growth rate may be affected
Solution Approach 1:
The substrate temperature during intermediate layer formation is reduced compared to the n-type clad layer formation temperature. This parameter change improves wettability and interface quality, reducing dislocation propagation. The temperature is carefully controlled within a specific range to achieve both good interface quality and acceptable growth rate, balancing manufacturing precision with productivity.
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 solution significantly increases light output by improving crystal quality and reducing dislocation-related losses, achieving higher efficiency in deep ultraviolet light emission.
Implementation Method 1
the wettability at the interface occurring when the intermediate layer is formed is improved
Implementation Method 2
the propagation of threading dislocation to the active layer is inhibited
Data Source
AI summary
A semiconductor light emitting device includes: an n-type clad layer made of an n-type aluminum gallium nitride (AlGaN)-based semiconductor material containing silicon (Si); an intermediate layer provided on the n-type clad layer and containing Si; an active layer of an AlGaN-based semiconductor material provided on the intermediate layer; and a p-type semiconductor layer provided on the active layer. A distribution of an Si concentration in a direction in which the n-type clad layer, the intermediate layer, and the active layer are stacked has a local peak at least at a position of the intermediate layer.