Nitride Semiconductor Light Emitting Device Mask Layer Growth

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Solution Overview

Problem

Nitride semiconductor light emitting devices face reduced electrical and optical characteristics due to high defect density caused by stress from lattice mismatching with hetero substrates, particularly in high-power applications where improved epitaxial layer quality and luminous efficiency are needed.

Innovation Solution

A method involving the use of a mask layer for growth on light emitting device chips, where a mask layer is formed on a substrate, openings are created for forming light emitting structures, and conductivity type nitride semiconductor layers are grown within these openings, reducing stress between the epitaxial layer and substrate, and allowing for easier separation and electrical connection of devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hetero substrate such as sapphire substrate is used for nitride semiconductor single crystal growth, then the device structure can be formed, but high defect density occurs due to stress caused by lattice mismatching, which reduces electrical and optical characteristics

Engineering Contradiction:

Improveelectrical and optical characteristicsVSAvoidstress from lattice mismatching

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the growth substrate into multiple separate chips instead of using a single large hetero substrate. By segmenting the substrate into smaller individual chips, the lattice mismatch stress is reduced in each chip, thereby decreasing defect density and improving electrical and optical characteristics while maintaining the benefits of hetero substrate growth.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If conventional growth methods are used without mask layer, then the growth process is simpler, but stress between epitaxial layer and substrate increases, reducing quality and luminous efficiency

Engineering Contradiction:

Improvegrowth process simplicityVSAvoidepitaxial layer quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a mask layer as an intermediary component during the growth process. This mask layer serves as a physical barrier that prevents lateral growth and reduces stress between the epitaxial layer and substrate. Although it adds a step to the manufacturing process, it significantly improves epitaxial layer quality and luminous efficiency by controlling the growth morphology and reducing defect formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If high-power applications are implemented, then the device power output increases, but defect density and stress effects become more pronounced, reducing luminous efficiency

Engineering Contradiction:

Improvedevice power outputVSAvoidluminous efficiency

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

By dividing the substrate into multiple small chips, each chip can be optimized for high-power operation with reduced stress and defect density. The segmented structure allows better heat dissipation and stress distribution, enabling high-power applications to maintain high luminous efficiency without the detrimental effects of lattice mismatching that plague single large substrate devices.

Inventive Principle:

Principle #1Segmentation

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 enhances electrical and optical characteristics of nitride semiconductor light emitting devices by reducing stress and improving luminous efficiency, facilitating easier separation and reducing errors in subsequent processes like scribing.

Implementation Method 1

using a mask layer for growth on the basis of light emitting device chips to reduce stress between an epitaxial layer and a substrate

Methodology Applied

Scientific EffectStress reduction through physical separation:

Implementation Method 2

forming a light emitting structure by sequentially growing a first conductivity type nitride semiconductor layer, an active layer, and a second conductivity type nitride semiconductor layer on the substrate through each of the openings of the mask layer

Methodology Applied

Scientific EffectEpitaxial growth: Epitaxy

Data Source

PatentUS7781248B2Method of manufacturing nitride semiconductor light emitting device and nitride semiconductor light emitting device manufactured using the method

Publication Date: 2010.08.24 SAMSUNG ELECTRONICS CO LTD

AI summary

There are provided a method of manufacturing a nitride semiconductor light emitting device and a nitride semiconductor light emitting device manufactured using the same. A method of manufacturing a nitride semiconductor light emitting device according to an aspect of the invention includes: forming a mask layer on a substrate; removing a portion of the mask layer to form openings provided as regions where light emitting structures are formed; forming a light emitting structure by sequentially growing a first conductivity type nitride semiconductor layer, an active layer, and a second conductivity type nitride semiconductor layer on the substrate through each of the openings of the mask layer; and forming first and second electrodes to be electrically connected to the first and second conductivity type nitride semiconductor layers, respectively.