Deep-UV AlGaN Active Layer Structure for Flatness and Electron Injection
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Solution Overview
Problem
Semiconductor light-emitting elements that emit deep ultraviolet light face challenges in light emission characteristics due to the insertion of a photonic crystal structure between the n-type clad layer and the active layer, leading to poorer electron injection efficiency and light emission characteristics.
Innovation Solution
A semiconductor light-emitting element configuration with an n-type clad layer, a planarizing layer, a barrier layer, and a well layer of AlGaN-based semiconductor materials, where the AlN molar fraction of the planarizing layer is lower than the barrier layer, and the ground level of the conduction band of the planarizing layer is higher than that of the well layer, inhibiting light emission in the planarizing layer and enhancing it in the well layer, thereby improving light emission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photonic crystal structure is inserted between the n-type clad layer and the active layer to enhance the flatness of the active layer, then the flatness is improved, but the electron injection efficiency deteriorates and light emission characteristics worsen
Solution Approach 1:
A planarizing layer with a specific AlN molar fraction (lower than the barrier layer) is introduced as an intermediary between the n-type clad layer and the active layer. This planarizing layer serves as a mediator that improves the flatness of the active layer while minimizing the negative impact on electron injection efficiency by having a lower AlN composition compared to the barrier layer.
Solution Approach 2:
The AlN molar fraction of the planarizing layer is specifically controlled to be lower than that of the barrier layer. By adjusting this compositional parameter, the patent achieves a balance between obtaining sufficient flatness improvement and maintaining adequate electron injection efficiency, resolving the contradiction between these two requirements.
2Manufacturing precision
If the AlN molar fraction of the planarizing layer is increased to improve flatness, then the flatness improvement is enhanced, but light emission in the planarizing layer increases which degrades light emission characteristics
Solution Approach 1:
The AlN molar fraction of the planarizing layer is precisely controlled to be lower than that of the barrier layer. This parameter optimization allows the planarizing layer to provide sufficient flatness improvement for the well layer while keeping the AlN composition low enough to suppress light emission within the planarizing layer itself, thereby preventing degradation of light emission characteristics.
Solution Approach 2:
The planarizing layer is designed with a specific local composition (lower AlN molar fraction than the barrier layer) that is optimized for its dual function: providing flatness improvement while suppressing unwanted light emission. This localized compositional control allows different regions of the structure to have different properties suited to their specific functions.
Data Source
AI summary
A semiconductor light-emitting element includes: an n-type clad layer of an n-type AlGaN-based semiconductor material; an active layer including a planarizing layer of an AlGaN-based semiconductor material provided on the n-type clad layer, a barrier layer of an AlGaN-based semiconductor material provided on the planarizing layer, and a well layer of an AlGaN-based semiconductor material provided on the barrier layer; and a p-type semiconductor layer provided on the active layer. The active layer emits deep ultraviolet light having a wavelength of 360 nm or shorter, and a ground level of a conduction band of the planarizing layer is lower than a ground level of a conduction band of the barrier layer and higher than a ground level of a conduction band of the well layer.