Vertical LED Fabrication Pre-Diffusion Metal Layer
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Solution Overview
Problem
Infrared light-emitting diodes face issues with metal diffusion from the reflective layer into the epitaxial layer during high-temperature fusion, leading to reduced light extraction efficiency due to black ohm-contact holes that absorb light.
Innovation Solution
A fabrication method for vertical light-emitting diodes involves growing a transparent insulating layer with through-holes, a metal reflective layer that pre-diffuses metal molecules at a controlled temperature, and high-temperature fusion to form a mixed interface, reducing metal diffusion and improving ohm-contact quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature fusion is adopted to obtain good ohm-contact effect, then contact quality is improved, but metal diffusion to the epitaxial layer increases and light extraction efficiency decreases
Solution Approach 1:
The patent applies preliminary action by performing pre-diffusion of metal molecules at controlled temperature (130-170°C) during the growth process before the high-temperature fusion step. This preliminary diffusion prepares the metal-semiconductor interface to reduce subsequent metal diffusion during high-temperature fusion, thus maintaining good ohm-contact quality while minimizing harmful metal diffusion into the epitaxial layer.
2Reliability
If high temperature fusion is used to form ohm contact, then contact resistance is reduced, but light absorption by ohm contact holes increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the temperature parameter during metal layer growth (130-170°C) to achieve optimal pre-diffusion conditions. This temperature control creates a mixed interface that reduces metal diffusion into the semiconductor layer, resulting in lighter-colored ohm contact holes that absorb less light while maintaining low contact resistance.
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 method enhances light extraction efficiency by minimizing metal diffusion and improving the appearance of ohm-contact holes, resulting in increased luminance of infrared light-emitting diodes.
Implementation Method 1
metal molecules in the metal reflective layer pre-diffuse from the holes to the second semiconductor layer to form a mixed interface
Implementation Method 2
heating temperature in Step 3) is T1, wherein, 130° C.≤T1≤170° C.; through heating, metal molecules in the metal reflective layer pre-diffuse
Implementation Method 3
the working temperature of the high-temperature fusion in Step 4) is T2, wherein 450° C.≤T2≤520° C.
Data Source
AI summary
A fabrication method of a vertical light-emitting diode, such as an infrared light-emitting diode, includes heating the reaction chamber during growth of the reflective layer to pre-diffuse the metal molecules of the reflective layer into the epitaxial layer. As a result, the diffusion of the metal molecules in the reflective layer into the epitaxial layer during high-temperature fusion of the reflective layer and the epitaxial layer slows down, and the blackness level of conventional ohm contact holes is reduced.