GaN LED Surface Roughening for Light Extraction
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Solution Overview
Problem
Obtaining sufficient brightness and efficiency from GaN-LEDs has been a challenge due to limitations in light output and extraction efficiency.
Innovation Solution
A vertical structure GaN-LED with a treated surface featuring micro- and macro-roughened textures is fabricated using ion implantation and additional processes like wet etching or KrF laser treatments, enhancing light extraction efficiency by scattering photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional planar surface is used in GaN-LED, then the device structure is simple and easy to manufacture, but the light extraction efficiency is insufficient and brightness is limited
Solution Approach 1:
The patent applies surface curvature by creating a roughened texture on the GaN layer surface through ion implantation. This curvature transforms the planar interface into a non-planar surface with varying angles, enabling photons to escape at multiple angles and significantly improving light extraction efficiency and overall light output.
Solution Approach 2:
The patent creates a porous-like roughened surface structure on the GaN layer by inducing an amorphous region through ion implantation. This roughened texture increases the effective surface area and creates multiple scattering interfaces, allowing more light to be extracted from the LED while maintaining electrical performance.
2Illumination intensity
If ion implantation is used to treat the GaN layer surface, then light extraction efficiency is significantly improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent replaces conventional mechanical or chemical etching methods with ion implantation to create the roughened surface. This substitution allows for precise control of the roughening depth and morphology through ion energy and dosage parameters, achieving consistent light extraction improvement while maintaining manufacturability through a well-established semiconductor processing technique.
3Illumination intensity
If the GaN layer surface is roughened to increase light output, then radiation performance is improved, but electrical performance may be affected
Solution Approach 1:
The patent applies local quality by creating a roughened texture only in the optical emission region of the GaN layer through controlled ion implantation. The ion implantation parameters (energy, dosage, pattern) are optimized to roughen only the surface layer that interacts with light, while preserving the bulk crystal quality and electrical properties of the GaN layer, thus improving radiation performance without compromising electrical performance.
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 treated surface significantly increases light output and extraction efficiency of the LED, improving its radiation performance without affecting electrical performance.
Implementation Method 1
The treatment includes performing an ion implantation process on the GaN layer
Implementation Method 2
enhancing light extraction efficiency by scattering photons
Data Source
AI summary
A device includes: a substrate; and a doped III-V compound layer disposed over the substrate; wherein: the doped III-V compound layer includes an upper boundary; the upper boundary has a micro-roughened texture and a macro-roughened texture where the micro-roughened texture located on; and the upper boundary includes dopant ions that are not present in a remainder of the doped III-V compound layer underneath the upper boundary.