Vertical Light-Emitting Device Passivation for Leakage Current
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Solution Overview
Problem
Vertical light-emitting devices fail due to high reverse leakage current, primarily caused by metal migration and impurities on the conductive structure and sidewalls.
Innovation Solution
A method for manufacturing light-emitting devices involves forming a passivation layer on the light-emitting structure and exposed conductive structures using a combination of dry and wet etching techniques to reduce reverse leakage current, including the formation of a first passivation layer on the light-emitting structure and a second passivation layer on the conductive structure and sidewalls, which can be a single-layer or multilayer structure, including a DBR structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vertical light-emitting device is manufactured without passivation, then the manufacturing process is simple, but the device fails due to high reverse leakage current caused by metal migration and impurities
Solution Approach 1:
The patent applies preliminary action by forming passivation layers on the sidewalls of the light-emitting structure and conductive structures during the manufacturing process, before the device is put into operation. This prevents metal migration and impurity attachment that would otherwise cause high reverse leakage current and device failure, thereby improving reliability without requiring additional post-manufacturing steps.
Solution Approach 2:
The passivation layer acts as an intermediary between the conductive structures/light-emitting structure and the external environment. This intermediate layer prevents direct contact between metal conductors and ambient contaminants, blocking metal migration and impurity attachment, thus reducing reverse leakage current while maintaining the overall device structure.
2Reliability
If passivation layers are formed on all surfaces, then reverse leakage current is reduced, but light extraction efficiency decreases due to additional interfaces
Solution Approach 1:
The patent applies local quality by selectively forming passivation layers only on specific surfaces where needed - specifically on the sidewalls of the light-emitting structure and conductive structures where metal migration occurs, while leaving the light-emitting surfaces uncovered or minimally passivated. This localized approach prevents reverse leakage current without creating unnecessary interfaces that would reduce light extraction 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 method effectively reduces the failure rate of light-emitting devices by minimizing reverse leakage current and enhancing light extraction through the formation of tilt sidewalls, thereby improving the device's reliability and efficiency.
Implementation Method 1
The step of removing a part of the light-emitting structure comprises the steps of: dry etching a part of the light-emitting structure in the street area; and wet etching a remaining part of the light-emitting structure in the street area
Implementation Method 2
The step of removing a part of the light-emitting structure comprises the steps of: dry etching a part of the light-emitting structure in the street area; and wet etching a remaining part of the light-emitting structure in the street area
Implementation Method 3
forming a passivation layer on the light-emitting structure in the chip areas and on the exposed conductive structure in the street areas
Data Source
AI summary
A method for manufacturing a light-emitting device comprising the steps of: providing a first substrate, a chip area, and a street area; forming a light-emitting structure on the first substrate; forming a conductive structure between the first substrate and the light-emitting structure; removing a part of the light-emitting structure in the street area to expose a sidewall of the light-emitting structure in the chip area; forming a first passivation layer on the light-emitting structure in the chip area; forming a second passivation layer on the conductive structure in the street area, on the sidewalls of the light-emitting structure, and on the sidewalls of the first passivation layer; forming a through-hole in the first passivation layer, and forming an electrode in the through-hole.