LED Reflective Mesa Structure for Light Extraction and ESD Endurance
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Solution Overview
Problem
Current light-emitting devices face challenges in optimizing the arrangement of insulating and metal reflective layers to enhance light extraction efficiency and electrical stress endurance, particularly in the design of the semiconductor mesa and reflective structure openings.
Innovation Solution
The light-emitting device incorporates a semiconductor mesa with an active layer and a metal reflective layer, where the insulating reflective structure has openings exposing the contact electrode, and a connection layer fills these openings, with the metal reflective layer covering the insulating structure openings, optimizing the pitch and arrangement to improve light extraction and electrical stress resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the insulating reflective structure has openings exposing the contact electrode, then light extraction efficiency is improved, but electrical stress endurance deteriorates
Solution Approach 1:
The reflective structure is segmented into multiple openings rather than a continuous layer, allowing light to pass through while maintaining electrical isolation. The openings are strategically positioned to expose contact electrodes for light extraction while the insulating material between openings provides electrical stress protection.
Solution Approach 2:
The insulating reflective structure has non-uniform properties: openings are created at specific locations where light extraction is needed, while the surrounding insulating material maintains electrical protection. The pitch and size of openings are locally optimized to balance optical and electrical requirements.
2Reliability
If the metal reflective layer covers the insulating structure openings, then electrical stress resistance is improved, but light extraction efficiency deteriorates
Solution Approach 1:
The reflective structure uses a composite of insulating material and metal reflective layer. The insulating material provides electrical stress resistance while the metal layer enhances reflectivity. The combination is arranged in openings and covering layers to simultaneously achieve both electrical protection and light extraction.
Solution Approach 2:
The solution moves from a two-dimensional planar reflective layer to a three-dimensional structure with openings at different levels. The metal reflective layer covers the top surfaces of insulating structures while leaving side surfaces and specific openings exposed, creating multi-level optical paths for light extraction while maintaining electrical protection.
3Area of stationary object
If the pitch between the contact electrode and semiconductor mesa is reduced, then device area is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The pitch between contact electrode and semiconductor mesa is optimized to specific parameter ranges. The insulating reflective structure openings are designed with controlled pitch and size parameters that enable reduced device area while maintaining manufacturability through standard fabrication processes.
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 configuration enhances light extraction efficiency and increases the endurance against electrical over stress and electrostatic discharge, leading to improved brightness and reliability of the light-emitting device.
Implementation Method 1
a metal reflective layer covering the connection layer and filling into the plurality of insulating reflective structure openings of the insulating reflective structure
Implementation Method 2
an insulating reflective structure covering the contact electrode and comprising a plurality of insulating reflective structure openings to expose the contact electrode
Data Source
AI summary
A light-emitting device comprises a first semiconductor layer; a semiconductor mesa, comprising an active layer and a second semiconductor layer and comprising an inclined surface; a contact electrode covering the second semiconductor layer and comprising a first side surface; an insulating reflective structure covering the contact electrode and comprising a plurality of insulating reflective structure openings; a connection layer covering the insulating reflective structure and filling into the plurality of insulating reflective structure openings, and comprising a second side surface; and a metal reflective layer covering the connection layer and filling into the plurality of insulating reflective structure openings, and comprising a third side surface; wherein in a cross-sectional view of the light-emitting device, a first pitch is between the first side surface and the inclined surface, a third pitch is between the third side surface and the inclined surface, and the third pitch is smaller than the first pitch.