GaN LED Structure With Conductive DBR and Beveled Light Extraction
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Solution Overview
Problem
Light-emitting diodes (LEDs) manufactured with gallium nitride-based materials suffer from low light-emitting efficiency due to their vertical structure and high refractive index, causing most light to be reflected and confined within the chip.
Innovation Solution
A semiconductor structure with a conductive Distributed Bragg Reflector (DBR) structure and beveled sidewalls is developed, featuring a gallium nitride-based material system with alternating porous conductive layers and protrusions to enhance light reflection and emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a vertical structure is used in gallium nitride-based LEDs, then the manufacturing process is simplified, but light-emitting efficiency deteriorates due to light reflection and confinement
Solution Approach 1:
The patent transforms the traditional vertical light emission structure into a micro-prism array structure with specific geometric angles (45-60 degrees). This dimensional change in the emission surface geometry enables light to be directed outward at optimized angles, breaking the total internal reflection constraint of vertical structures and significantly improving light extraction efficiency without complicating the overall manufacturing process
2Reliability
If the refractive index of gallium nitride is increased to improve material performance, then device functionality is enhanced, but light reflection increases causing lower light-emitting efficiency
Solution Approach 1:
The patent converts the harmful effect of high refractive index (which causes total internal reflection) into a beneficial feature by designing micro-prism structures that utilize refraction at specific angles. The high refractive index material, when shaped into prisms with 45-60 degree angles, actually enhances light extraction by directing light at angles that escape the critical angle constraint, transforming the reflection problem into an extraction solution
3Loss of energy
If the device size is increased to provide larger reflective surface area, then light-emitting efficiency improves, but device compactness deteriorates
Solution Approach 1:
The patent introduces a third-dimensional geometric structure (micro-prism array) on the light emission surface, transforming a two-dimensional surface into a three-dimensional optical structure. This enables the device to achieve high light extraction efficiency within a compact footprint by utilizing angular light redirection rather than relying on increased surface area, maintaining device compactness while improving efficiency
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 significantly improves light-emitting efficiency by increasing the reflective surface area and allowing more light to be directed towards the emission surface without increasing the device size, while the DBR structure aids in wavelength resonance.
Implementation Method 1
the second semiconductor layer is a conductive Distributed Bragg Reflector (DBR) structure
Implementation Method 2
most of the light is reflected when reaching the surface of the LED
Implementation Method 3
a side surface of each of the second protrusions is a bevel
Implementation Method 4
most of the light is reflected when reaching the surface of the LED, so that a large amount of light is confined to the inside of the LED chip
Data Source
AI summary
The present application provides a semiconductor structure and a manufacturing method therefor, and a light-emitting device and a manufacturing method therefor. The semiconductor structure includes a substrate, a first semiconductor layer, an isolation layer, an active layer, a second semiconductor layer, a first electrode and a second electrode. The second semiconductor layer is a conductive DBR structure. The first semiconductor layer includes a flat portion, a first protrusion and a second protrusion stacked sequentially in a vertical direction, the second protrusions correspond one-to-one to the first through-holes, and the second protrusions are arranged at intervals, and the side surface of the second protrusions are beveled. The active layer, the second semiconductor layer, and the first electrode are provided on the second protrusions of the first semiconductor layer stacked in sequence. The isolation layer is provided with a second through-hole, and the second electrode is formed in the second through-hole.