Semiconductor LED Display Structure for Low-Damage Lift-Off
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Solution Overview
Problem
Current display devices using semiconductor light-emitting diodes face challenges such as damage during transfer due to heat or chemicals and high manufacturing costs, particularly when separating the diodes from growth substrates, and also suffer from surface leakage current issues.
Innovation Solution
A display device structure incorporating semiconductor light-emitting diodes with specific layer configurations, including conductive electrodes, semiconductor layers, an active layer, and protrusions made of porous materials, along with an intermediate layer and oxide layers to prevent damage and reduce manufacturing costs, and a manufacturing method involving electropolishing and mechanical lift-off to minimize surface leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor light-emitting diodes are separated from growth substrate using conventional methods, then the diodes can be transferred to display devices, but the diodes are damaged due to heat or chemicals
Solution Approach 1:
A sacrificial layer is introduced as an intermediary between the semiconductor light-emitting diode and the growth substrate. This sacrificial layer is designed to be selectively removed through electropolishing, enabling clean separation of the diode from the substrate without exposing it to damaging heat or chemicals. The sacrificial layer acts as a mediator that facilitates transfer while protecting the diode structure.
Solution Approach 2:
The patent replaces conventional thermal or chemical separation methods with an electropolishing process. Instead of using heat or chemicals to separate the diode from the substrate, an electrical field is applied to selectively dissolve the sacrificial layer through electrochemical reactions, providing a gentler separation mechanism that avoids damage to the semiconductor structures.
2Ease of manufacture
If conventional separation methods are used, then diode transfer is achieved, but manufacturing cost increases due to high facility cost
Solution Approach 1:
The sacrificial layer is designed as a disposable, consumable component that is intentionally created for the purpose of enabling separation and then selectively removed. This sacrificial layer can be formed using standard semiconductor fabrication processes and is discarded after serving its function, replacing expensive specialized facilities with a cost-effective material-based solution.
3Reliability
If semiconductor light-emitting diodes are used in display devices, then excellent display characteristics are achieved, but surface leakage current occurs
Solution Approach 1:
The patent applies different properties to different regions of the semiconductor structure. An intermediate layer with specific electrical properties is introduced between the n-type semiconductor layer and the undoped semiconductor layer. This intermediate layer has localized properties that differ from adjacent layers, creating a potential barrier that specifically addresses surface leakage current at critical interfaces while maintaining the overall performance of the light-emitting diode.
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 effectively prevents damage to semiconductor light-emitting diodes during separation and reduces manufacturing costs while enhancing the efficiency of the diodes by minimizing surface leakage current and improving light emission characteristics.
Implementation Method 1
an electropolishing step of electrochemically etching the sacrificial layer to form a porous structure
Data Source
AI summary
Discussed is a display device having a plurality of semiconductor light-emitting diodes. At least one of the semiconductor light-emitting diodes has a first conductive electrode and a second conductive electrode; a first conductive semiconductor layer on which the first conductive electrode is disposed; a second conductive semiconductor layer that overlaps with the first conductive semiconductor layer, and the second conductive electrode being disposed on the second conductive semiconductor layer; an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; an undoped semiconductor layer disposed on the second conductive semiconductor layer; and protrusions formed of a porous material allowing electropolishing, and on the undoped semiconductor layer.