Semiconductor Light-Emitting Electrode Structure for UV Reflectance Stability
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Solution Overview
Problem
Semiconductor light-emitting elements with n-side electrodes composed of Al without Au suffer from corrosion during energized use, leading to decreased ultraviolet reflectance and light output.
Innovation Solution
Incorporating a TiN layer in the n-side current diffusion layer over a wider region than the n-side contact electrode, and a p-side current diffusion layer with a stacked structure of TiN, metal, and TiN layers to maximize the light-emitting area and prevent corrosion, thereby maintaining reflectance and light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the n-side electrode is formed using Al without Au, then the ultraviolet reflectance is increased, but the electrode is corroded during energized use resulting in lowered ultraviolet reflectance
Solution Approach 1:
The n-side contact electrode uses a composite structure of Ti and Al layers, where Ti provides corrosion resistance and Al provides high ultraviolet reflectance. This composite material approach resolves the contradiction by combining materials with complementary properties to achieve both high reflectance and corrosion resistance simultaneously.
2Area of stationary object
If the p-side contact electrode occupies maximum area on the upper surface of the p-type semiconductor layer, then the light-emitting layer area is maximized, but the current diffusion area is reduced
Solution Approach 1:
The current diffusion layer extends laterally beyond the vertical projection of the contact electrode, utilizing the horizontal dimension to provide current diffusion pathways without reducing the vertical contact area. This dimensional extension allows both maximum light-emitting area and sufficient current diffusion capability.
Solution Approach 2:
The electrode structure is segmented into distinct functional layers: the contact electrode for electrical connection, the current diffusion layer for current distribution, and the light-emitting layer for photon generation. This segmentation allows each layer to be optimized for its specific function without compromising the others.
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 effectively suppresses corrosion of the n-side contact electrode and maintains high light output by maximizing the reflective area and preventing metal migration, ensuring stable performance during energized use.
Implementation Method 1
with the n-side current diffusion layer having the TiN layer provided on the n-side contact electrode over a region wider than the formation region of the n-side contact electrode, the n-side contact electrode may be suppressed from being corroded during energized use
Implementation Method 2
the n-side contact electrode may be suppressed from being corroded during energized use. This successfully suppresses decrease in reflectance of the n-side contact electrode that functions as a reflective electrode, and suppresses the light output from declining during energized use
Implementation Method 3
Each of the p-side current diffusion layer and the n-side current diffusion layer may have a stacked structure in which a TiN layer, a metal layer and a TiN layer are stacked in order
Implementation Method 4
maintaining reflectance and light output... preventing metal migration, ensuring stable performance during energized use
Data Source
AI summary
The semiconductor light-emitting element has an n-type semiconductor layer; an active layer provided on a first upper surface of the n-type semiconductor layer; a p-type semiconductor layer provided on the active layer; a p-side contact electrode provided in contact with the upper surface of the p-type semiconductor layer; a p-side current diffusion layer provided on the p-side contact electrode in a region narrower than a formation region of the p-side contact electrode; a p-side pad electrode provided on the p-side current diffusion layer; an n-side contact electrode provided in contact with a second upper surface of the n-type semiconductor layer; an n-side current diffusion layer provided on the n-side contact electrode over a region wider than a formation region of the n-side contact electrode, and including a TiN layer; and an n-side pad electrode provided on the n-side current diffusion layer.