Semiconductor Light Emitting Element Silver Electrode ALD Coating
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Solution Overview
Problem
Conventional semiconductor light emitting elements face issues with light output reduction due to migration and discoloration of reflective films, as the protective films formed using sputtering or vapor deposition methods do not allow for uniform coverage, leading to absorption of light by thick protective films.
Innovation Solution
A semiconductor light emitting element is manufactured using a method that includes forming a silver-containing electrode and coating an insulating layer, such as aluminum oxide or silicon dioxide, over the side surfaces of the electrode using atomic layer deposition to ensure uniform thickness and prevent silver migration, thereby maintaining high light output and suppressing discoloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film is formed using sputtering or vapor deposition method, then migration and discoloration of the reflective film are prevented, but the protective film cannot be formed uniformly due to structural obstacles, requiring increased thickness that absorbs light and reduces light output
Solution Approach 1:
The patent changes the deposition method from sputtering/vapor deposition to atomic layer deposition (ALD), fundamentally altering the deposition parameters to achieve uniform thin film formation. ALD allows precise control of film thickness at the nanometer scale, enabling formation of uniformly thick protective layers that prevent silver migration while minimizing light absorption.
Solution Approach 2:
The patent replaces the physical sputtering/vapor deposition process with a chemical ALD process. Instead of using kinetic energy to deposit material, ALD uses sequential chemical reactions to form the protective film, enabling conformal coverage on complex electrode structures without requiring thick films.
2Reliability
If the thickness of the protective film is increased to prevent migration or discoloration of the reflective film, then reliability is improved, but the thick protective film absorbs light and decreases light output
Solution Approach 1:
The patent changes the deposition method to ALD, which enables precise control of film thickness at the nanometer scale. This allows formation of uniformly thin protective layers that provide adequate protection against discoloration while minimizing light absorption, resolving the trade-off between reliability and energy loss.
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 prevents silver migration and maintains high light output by ensuring uniform thickness of the insulating layer, which minimizes light absorption and enhances light extraction efficiency.
Implementation Method 1
forming an insulating layer coating over at least a side surface of the silver-containing layer from the upper surface of the second conductivity type semiconductor layer by an atomic layer deposition method
Data Source
AI summary
[Object][Means for Solving Problem] A method for manufacturing of a semiconductor light emitting element has; forming a semiconductor layer laminated of a first conductivity type semiconductor layer, a light emitting layer and a second conductivity type semiconductor layer, in this order, forming an electrode including a silver-containing layer in contact with an upper surface of the second conductivity type semiconductor layer, forming an insulating layer coating over at least a side surface of the silver-containing layer from the upper surface of the second conductivity type semiconductor layer by an atomic layer deposition method.