ITO-Al Composite Transparent Electrode for UV LED
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Solution Overview
Problem
Current transparent electrode technologies for UV LEDs face challenges in achieving high conductivity and transmittance, leading to low light extraction efficiency and increased manufacturing costs due to the need for additional processes like Laser Lift Off and reflection film deposition, which also result in thermal damage and reduced price competitiveness.
Innovation Solution
A semiconductor device with a transparent electrode made of a resistance change substance that forms conductive paths by applying a voltage, allowing for improved ohmic contact and high transmittance in the UV region without the need for removing the growth substrate, thereby simplifying the manufacturing process and enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent electrode material with high transmittance in UV region is used, then transmittance improves, but conductivity becomes very low and ohmic contact with semiconductor cannot be achieved
Solution Approach 1:
The patent uses ITO-Al composite materials where the aluminum component provides high electrical conductivity necessary for ohmic contact with the semiconductor layer, while the composite structure maintains high UV transmittance. The synergistic combination allows the electrode to satisfy both optical (UV transmittance) and electrical (conductivity and ohmic contact) requirements that single materials cannot achieve alone.
Solution Approach 2:
The patent adjusts the aluminum content parameter in the ITO-Al composite (0-30 at% Al) to optimize the balance between conductivity and transmittance. By controlling the Al concentration, the electrode achieves sufficient electrical conductivity for reliable ohmic contact while maintaining high UV region transmittance, thus resolving the trade-off between these two critical properties.
2Illumination intensity
If metal electrode pad is directly formed on semiconductor layer, then transmittance issue is avoided, but ohmic contact cannot be performed due to great difference in work functions
Solution Approach 1:
The patent introduces ITO-Al composite transparent electrode as an intermediary layer between the metal electrode pad and the semiconductor layer. This intermediate layer has suitable work function that enables ohmic contact with the semiconductor, eliminating the work function mismatch problem that occurs with direct metal-semiconductor contact. The intermediary layer thus resolves the contradiction by providing both electrical compatibility for ohmic contact and optical transparency.
3Illumination intensity
If additional processes like Laser Lift Off and reflection film deposition are used to improve UV LED performance, then light extraction efficiency improves, but manufacturing cost increases and thermal damage occurs
Solution Approach 1:
The patent extracts and eliminates the need for additional post-growth processes like Laser Lift Off and separate reflection film deposition by integrating the reflective and transparent electrode functions directly into the ITO-Al composite structure formed during the semiconductor layer growth process. This extraction of unnecessary steps reduces manufacturing cost, simplifies the process, and avoids thermal damage while maintaining light extraction efficiency.
Solution Approach 2:
The patent merges multiple functions (transparent electrode, reflective layer, and UV-enhancing layer) into a single ITO-Al composite structure that is formed in-situ during semiconductor growth. This consolidation of multiple separate processes into one integrated structure eliminates the need for additional manufacturing steps, reduces cost, and prevents thermal damage from repeated high-temperature processes, while achieving the desired light extraction efficiency.
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 provides a semiconductor device with enhanced conductivity and reliability, improving light extraction efficiency and reducing manufacturing costs by eliminating the need for substrate removal and associated processes, while maintaining high transmittance across the UV and visible spectrum.
Implementation Method 1
a transparent electrode made of a resistance change substance and formed on one side of the semiconductor layer, in which conductive paths are formed by applying a voltage of a threshold voltage or more
Implementation Method 2
maintaining high transmittance across the UV and visible spectrum
Data Source
AI summary
A semiconductor device is disclosed, and the semiconductor device comprises: a semiconductor layer; and a transparent electrode which is formed from a resistance switching material and is formed on one side of the semiconductor layer, wherein the transparent electrode includes a channel on which an electron is capable of hopping and a conductive path formed by applying a voltage that is a threshold voltage or more, and the threshold voltage for forming the conductive path is lowered by the channel.