LED Epitaxy Structure Sidewall Dielectric Layer for Laser Substrate Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The traditional method of removing sapphire substrates from AlGaInN LED epitaxy structures using a laser beam can lead to decomposition of the adhesive layer, causing peeling between the conductive substrate and the epitaxy structure, and results in instability due to strain between the adhesive layer and the epitaxy structure.
Innovation Solution
A transparent dielectric layer is formed on the sidewall of the LED epitaxy structure during fabrication, which protects the structure and enhances adhesion between the conductive substrate and the epitaxy structure, preventing peeling and improving substrate removal by using a laser beam to decompose the substrate without affecting the adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a laser beam is used to remove the sapphire substrate by decomposing the n-type semiconductor layer, then the substrate can be easily removed, but the adhesive layer may be decomposed causing peeling between the conductive substrate and the AlGaInN LED epitaxy structure
Solution Approach 1:
A residue of the n-type semiconductor layer is intentionally left on the lower surface of the AlGaInN LED epitaxy structure before substrate removal. This residue acts as a protective barrier that prevents the laser beam from directly illuminating the adhesive layer, thereby preventing decomposition of the adhesive layer while still allowing easy substrate removal through decomposition of the n-type layer.
2Productivity
If the residue of the n-type semiconductor layer is made thin enough to be easily removed, then the substrate removal is facilitated, but the laser beam may pass through to the adhesive layer causing decomposition
Solution Approach 1:
The residue of the n-type semiconductor layer serves as an intermediary protective layer between the laser beam and the adhesive layer. It is thick enough to absorb or block the laser beam energy, preventing direct illumination of the adhesive layer, yet thin enough to be easily removed afterward through conventional etching methods.
3Ease of manufacture
If the laser beam is employed on the sapphire substrate, then the substrate can be removed, but the strain between the adhesive layer and the AlGaInN LED epitaxy structure increases causing instability and peeling
Solution Approach 1:
The transparent dielectric layer is formed on the sidewall of the AlGaInN LED epitaxy structure before substrate removal. This layer provides mechanical support and strain distribution, preventing peeling between layers that would otherwise occur due to strain generated during laser-based substrate removal.
Solution Approach 2:
The transparent dielectric layer acts as a cushioning element on the sidewall of the epitaxy structure, absorbing and distributing the strain generated during laser-induced substrate removal. This prevents concentration of stress at critical interfaces, thereby maintaining structural stability and preventing peeling.
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 transparent dielectric layer effectively prevents peeling between layers and enhances light output by ensuring the conductive substrate remains bonded to the epitaxy structure, while allowing easy removal of the substrate and improving the directional emission of light.
Implementation Method 1
The laser beam passes through the sapphire substrate, and decomposes the n-type semiconductor layer of the AlGaInN LED epitaxy structure, contacting the substrate, into Ga and N2
Implementation Method 2
Ga is melted by heat of a designated temperature, making the sapphire substrate easily removed
Implementation Method 3
the transparent dielectric layer protects the light emitting diode epitaxy structure, and improves the adhesion of the conductive substrate and the light emitting diode epitaxy structure
Implementation Method 4
to enhance the sidewall output of the light from the light emitting diode
Data Source
AI summary
A light emitting diode and its fabricating method are disclosed. A light emitting diode epitaxy structure is formed on a substrate, and then the light emitting diode epitaxy structure is etched to form a recess. The recess is then filled with a transparent dielectric material. An adhesive layer is utilized to adhere a conductive substrate and the light emitting diode epitaxy structure. Next, the substrate is removed.