High Brightness LED Structure with AlInP Current Barrier
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Solution Overview
Problem
Conventional high brightness LEDs suffer from reduced light-emitting efficiency due to the front electrode shielding the light emitted by the AlGaInP active layer, which restricts the current flow to the light-emitting region.
Innovation Solution
Incorporating a DBR layer to enhance light reflection and utilizing a highly-doped n-type AlInP island structure as a current barrier, positioned between the AlGaInP semiconductor stack and the p-type GaP window layer, to optimize current distribution and prevent the p-type ohmic electrode from shielding the light-emitting region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a front electrode is used to contact the p-type layer, then electrical connection is achieved, but light emission is shielded and light-emitting efficiency decreases
Solution Approach 1:
The patent divides the contact structure into multiple segments: a reflective electrode at the bottom reflecting light upward, side electrodes positioned at the edges, and a transparent conductive layer covering the active region. This segmentation allows electrical connection while minimizing light shielding by distributing contact points strategically.
Solution Approach 2:
The patent transitions from a planar electrode configuration to a three-dimensional structure by positioning electrodes at the bottom, sides, and top of the active region. The reflective electrode at the bottom reflects light upward through the active region, while side electrodes provide lateral contact, creating a multi-dimensional electrical connection network that preserves light emission paths.
2Reliability
If current is distributed across the entire device area, then electrical connection is achieved, but current flows through shielded regions reducing light-emitting efficiency
Solution Approach 1:
The patent creates different electrical properties in different regions: highly doped n-type and p-type contact regions for electrical connection, and a less doped or undoped active region for light emission. The transparent conductive layer has optimized doping to balance conductivity and transparency, allowing current to reach the active region without excessive shielding while maintaining electrical connection reliability.
Solution Approach 2:
The patent introduces a transparent conductive layer as an intermediary between the electrodes and the active region. This layer mediates current flow by providing a conductive path that is also transparent to light, allowing current to reach the active region for light generation while minimizing light absorption or reflection that would reduce emission efficiency.
3Reliability
If the p-type ohmic electrode is extended to improve current flow, then electrical connection is enhanced, but light shielding increases and light emission is reduced
Solution Approach 1:
The patent segments the current path by introducing a transparent conductive layer that distributes current across the active region without requiring extensive p-type electrode coverage. The current flows through the transparent conductive layer directly to the active region, eliminating the need for extended p-type electrodes that would shield light.
Solution Approach 2:
The patent replaces the mechanical/electrical connection approach (extending p-type ohmic electrode) with an optical/electrical hybrid approach using a transparent conductive layer. This layer provides both electrical conductivity and optical transparency, substituting the need for extensive metal electrode coverage that would mechanically block light paths.
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 DBR layer improves light reflection, and the n-type AlInP current barrier structure ensures more current flows to the AlGaInP semiconductor stack, thereby enhancing light-emitting efficiency and increasing the brightness of the LED.
Implementation Method 1
DBR (Distributed Bragg Reflector) is used to enhance the reflection of LED light
Implementation Method 2
an n-type AlInP is used as a current barrier structure, which can promote the light-emitting efficiency via making more input current flow to the AlGaInP semiconductor stack structure
Implementation Method 3
LED (Light Emitting Diode) emits light when electrons and electron holes recombine
Data Source
AI summary
The present invention discloses a high brightness LED structure, wherein a highly-doped n-type AlInP island structure is formed on a portion of the surface of an AlGaInP semiconductor stack structure and functions as a current barrier structure. The island structure is covered by a p-type window layer and positioned below a p-type ohmic electrode. The island structure can make more input current flow to the AlGaInP semiconductor stack structure not shielded by the light-emitting side electrode and thus can optimize the current distribution and promote the light-emitting efficiency.