Transparent Electrode Oxygen Control for LED Bonding
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Solution Overview
Problem
Gallium nitride compound semiconductor light-emitting devices face challenges in achieving low contact resistance and high bonding strength between transparent conductive oxide electrodes and p-type semiconductor layers, leading to increased forward voltage and reduced brightness, with existing methods requiring complex processes and potentially damaging etching.
Innovation Solution
A method involving the formation of a transparent positive electrode with a lower oxygen concentration than stoichiometric composition, followed by annealing in an oxygen-rich atmosphere and reannealing in an oxygen-free atmosphere, to reduce sheet resistance and enhance bonding strength without the need for contact holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent electrode made of transparent conductive oxide material (such as ITO) is formed on a p-type gallium nitride compound semiconductor layer, then light transmittance is improved and emission efficiency is enhanced, but contact resistance at the interface increases and bonding strength decreases
Solution Approach 1:
The patent changes the oxygen concentration parameter of the transparent conductive oxide material from stoichiometric composition to oxygen-deficient composition. Specifically, the oxygen concentration is controlled to be lower than the stoichiometric composition, which fundamentally alters the electrical properties of the material, reducing contact resistance while maintaining high light transmittance.
Solution Approach 2:
The patent applies different oxygen concentrations to different regions or layers of the transparent electrode structure. The transparent conductive oxide material has a specific oxygen-deficient region that provides low contact resistance, while other regions maintain appropriate oxygen content for structural stability and transmittance.
2Illumination intensity
If a transparent electrode made of transparent conductive oxide material is formed on a p-type semiconductor layer, then light emission efficiency is improved, but bonding strength between the electrode and semiconductor layer is insufficient causing peeling during wire bonding
Solution Approach 1:
The patent modifies the oxygen concentration parameter of the transparent conductive oxide material to create an oxygen-deficient composition. This parameter change enhances the bonding strength between the electrode and the p-type semiconductor layer, preventing peeling during wire bonding while maintaining high emission efficiency.
3Strength
If contact holes are formed in the transparent electrode to connect the bonding pad directly to the p-type semiconductor layer, then bonding strength is improved, but manufacturing complexity increases and etching damage occurs
Solution Approach 1:
The patent extracts or eliminates the need for contact holes from the manufacturing process. By forming the bonding pad directly on the transparent electrode without creating contact holes, the invention simplifies the manufacturing process and avoids etching damage to the semiconductor layer, while still achieving sufficient bonding strength through the oxygen-deficient transparent conductive oxide material.
4Reliability
If the oxygen concentration in the transparent conductive oxide material is reduced below stoichiometric composition, then contact resistance decreases and bonding strength improves, but light transmittance may be affected
Solution Approach 1:
The patent optimizes the oxygen concentration parameter to achieve a balance between contact resistance and light transmittance. By precisely controlling the oxygen concentration to be lower than stoichiometric composition but not excessively low, the invention achieves low contact resistance while maintaining adequate light transmittance for efficient light emission.
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 approach results in improved light emission efficiency, reduced forward voltage, and increased bonding strength, preventing electrode peeling during wire bonding, while simplifying the manufacturing process and maintaining high reliability.
Implementation Method 1
performing an annealing process on the transparent positive electrode in an atmosphere including oxygen
Implementation Method 2
performing a reannealing process on the transparent positive electrode in an oxygen-free atmosphere
Data Source
Figure 1~2
Figure 3~4
AI summary
An object of the present invention is to provide a semiconductor light-emitting device having a high light emission property and preventing an electrode from being peeled off during wire bonding. The present invention provides a method of manufacturing a semiconductor light-emitting device 1 in which an n-type semiconductor layer 13, a light-emitting layer 14, and a p-type semiconductor layer 15 are formed on a substrate 11, a transparent positive electrode 16 is formed on the p-type semiconductor layer 15, a positive electrode bonding pad 17 is formed on the transparent positive electrode 16, and a negative electrode bonding pad 18 is formed on the n-type semiconductor layer 13.