PEC Etching Control Layer for LED Light Extraction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing light emitting diode (LED) fabrication methods, particularly those using photoelectrochemical etching (PEC), face challenges in preventing damage to the active layer during the etching process, which affects the light extraction efficiency.

Innovation Solution

Incorporating a PEC etching control layer between the conductive semiconductor layers to prevent over-etching and protect the active layer, while forming roughness on the upper surface of the light emitting structure using PEC etching to enhance light extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If PEC etching is performed on the light emitting structure to form roughness for improving light extraction efficiency, then light extraction efficiency is improved, but the active layer is damaged due to over-etching

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidactive layer integrity

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

An etching control layer is introduced as an intermediary between the light emitting structure and the etching solution. This layer selectively prevents etching of the active layer while allowing etching of the light emitting structure to form roughness, thus protecting the active layer from damage while still achieving light extraction enhancement

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The etching control layer provides selective protection with different etching resistance properties to different regions/layers. It allows the light emitting structure to be etched for roughness formation while preventing etching of the active layer, achieving local differential etching behavior

Inventive Principle:

Principle #3Local quality

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 approach effectively prevents damage to the active layer during etching, thereby improving the light emitting efficiency of the LED device by forming a roughness that enhances light extraction without compromising the semiconductor layers.

Implementation Method 1

a photo electrochemical etching scheme (PEC) has been used

Methodology Applied

Scientific EffectPhotoelectrochemical etching: Photoelectric Effect

Implementation Method 2

A scheme for improving light extraction efficiency of the light emitting device has been proposed to form a roughness on an upper surface of a light emitting structure

Methodology Applied

Scientific EffectLight extraction: Refraction

Data Source

PatentEP2546893B1Light emitting device with a roughened surface and including an etching control layer for photoelectrochemical etching, light emitting device package, and light unit

Publication Date: 2019.07.31 LG INNOTEK CO LTD

Figure 1~2
Figure 3~4
Figure 5

AI summary

A light emitting device (100) includes a first conductive semiconductor layer (11,14) providing a roughness (17) on a upper surface thereof and including a PEC etching control layer (15); an active layer (12) under the first conductive semiconductor layer; a second conductive semiconductor layer (13) under the active layer; a reflective electrode (50) electrically connected to the second conductive semiconductor layer; and a first electrode (20) electrically connected to the first conductive semiconductor layer.