Nitride Semiconductor Substrate Structural Bodies for Light Extraction

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Solution Overview

Problem

Existing semiconductor light emitting devices using nitride semiconductors face challenges in increasing external quantum efficiency due to surface roughness and pit formation when patterning unevenness on substrates, leading to decreased light extraction efficiency and crystallinity.

Innovation Solution

A semiconductor light emitting device configuration with a substrate having specific structural bodies, where the substrate protrusion height and recess width satisfy certain ratios, preventing pit formation and enhancing crystallinity and light extraction efficiency by controlling the growth of nitride semiconductor layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If unevenness is patterned on the substrate to increase light extraction efficiency, then light extraction efficiency is improved, but pits form and surface flatness degrades

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidsurface flatness

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The substrate is designed with localized protrusions and recesses rather than uniform unevenness. Each protrusion has a controlled height and width ratio that creates specific growth conditions in localized areas, allowing light extraction enhancement without compromising overall surface flatness. The protrusions are strategically positioned and dimensioned to prevent pit formation while maintaining surface quality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention controls the geometric parameters of the protrusions and recesses, specifically the height-to-width ratio, to optimize both light extraction and surface flatness. By adjusting these parameters within specific ranges, the patent achieves a balance between enhancing light extraction efficiency and preventing surface degradation that would lead to pit formation.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If substrate unevenness is increased to improve light extraction, then light extraction efficiency is improved, but dislocation density increases and crystallinity decreases

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidcrystallinity

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

Rather than creating widespread surface unevenness, the patent introduces localized protrusions with controlled dimensions. These localized structures provide sufficient surface area variation for enhanced light extraction while maintaining a predominantly flat substrate that supports high-quality crystal growth and minimizes dislocation propagation throughout the nitride semiconductor layer.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The substrate protrusions and recesses are pre-formed with optimized geometric parameters before nitride semiconductor layer deposition. This preliminary structuring ensures that the subsequent epitaxial growth occurs on a controlled surface topology that promotes crystallinity while enabling light extraction enhancement, preventing dislocation formation from the outset.

Inventive Principle:

Principle #10Preliminary action

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 proposed configuration suppresses pit formation and dislocation density, resulting in improved light extraction efficiency and crystallinity, enhancing the reliability and performance of nitride semiconductor light emitting devices.

Implementation Method 1

nitride semiconductor layer growth substrate has a substrate major surface and a plurality of substrate structural bodies provided in the substrate major surface

Methodology Applied

Scientific EffectVapor phase deposition: Physical Vapour Deposition

Implementation Method 2

enhancing the reliability and performance of nitride semiconductor light emitting devices

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS9064997B2Semiconductor light emitting device, nitride semiconductor layer growth substrate, and nitride semiconductor wafer

Publication Date: 2015.06.23 SAMSUNG ELECTRONICS CO LTD

AI summary

According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer of a first conductivity type and having a major surface, a second semiconductor layer of a second conductivity type, and a light emitting layer provided between the first and second semiconductor layers. The major surface is opposite to the light emitting layer. The first semiconductor layer has structural bodies provided in the major surface. The structural bodies are recess or protrusion. A centroid of a first structural body aligns with a centroid of a second structural body nearest the first structural. hb, rb, and Rb satisfy rb/(2·hb)≦0.7, and rb/Rb<1, where hb is a depth of the recess, rb is a width of a bottom portion of the recess, and Rb is a width of the protrusion.