Carbide Substrate Reflective Layer Adhesion
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Solution Overview
Problem
Existing semiconductor light emitting elements face challenges in enhancing light takeoff efficiency and adhesion between the reflective layer and the carbide substrate, leading to potential issues with reflectivity and heat dissipation.
Innovation Solution
A method involving a reflective layer with silver as the main component, combined with oxide or nitride particles, is applied to the carbide substrate, enhancing adhesion and maintaining high reflectivity by forming a pseudo transition layer at the interface, which suppresses crystal grain growth and void generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective layer is provided on the carbide substrate to improve light takeoff efficiency, then reflectivity is improved, but adhesion between the reflective layer and substrate deteriorates
Solution Approach 1:
An adhesive layer comprising Ti, Al, or alloy thereof is introduced between the carbide substrate and the reflective layer (Ag, Al, or their alloys). This intermediary layer serves as a bridge that chemically bonds to both the substrate and the reflective layer, resolving the adhesion problem while preserving the optical reflection function.
Solution Approach 2:
The structure employs composite material design with multiple layers: carbide substrate + adhesive layer (Ti/Al alloy) + reflective layer (Ag/Al alloy). Each layer is optimized for its specific function - the substrate for mechanical support, the adhesive layer for bonding, and the reflective layer for optical reflection - creating a composite structure that achieves both strong adhesion and high reflectivity.
2Illumination intensity
If the reflective layer is made thicker to improve reflectivity, then light takeoff efficiency is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The reflective layer thickness is optimized to a specific range (50-200 nm) rather than made uniformly thick. This parameter optimization ensures sufficient reflectivity while maintaining thermal conductivity. Additionally, the adhesive layer material (Ti or Al) is selected for its excellent thermal conductivity to facilitate heat dissipation from the LED chip through the substrate.
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 improves light takeoff efficiency and reliability by ensuring strong adhesion between the reflective layer and the substrate, maintaining high reflectivity and heat dissipation, while preventing separation at the interface.
Implementation Method 1
a reflective layer is provided on the back of the substrate, thereby improving the reflectivity of light to the element structure side, and increasing the light takeoff efficiency
Implementation Method 2
an adhesive layer provided between the crystal substrate and the reflective layer
Data Source
AI summary
A method for manufacturing a semiconductor element includes providing a semiconductor layer on a carbide substrate, the carbide substrate having a semiconductor layer contact surface connected to the semiconductor layer and a reflective layer contact surface opposite to the semiconductor layer contact surface. A reflective layer is provided on the reflective layer contact surface of the carbide substrate. The reflective layer contains silver and at least one of oxide particles and nitride particles.