AlxGayIn1-x-yN Substrate Dislocation Management

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Solution Overview

Problem

Existing methods fail to produce AlxGayIn1-x-yN crystal substrates with large size and low dislocation density suitable for semiconductor devices, leading to variations in dislocation density and reduced performance.

Innovation Solution

A crystal growth method where dislocations in the AlxGayIn1-x-yN crystal are propagated parallel to the growth plane and released to the periphery, achieving a dislocation density range of 1×10^2 to 1×10^6 cm^-2, allowing for the fabrication of large-sized substrates with improved crystallinity and utilization efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the thickness of the grown crystal is increased to decrease dislocation density, then the dislocation density is reduced, but the effect is insufficient and variations in dislocation density remain in the substrate plane

Engineering Contradiction:

Improvedislocation densityVSAvoiduniformity of dislocation density

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent extracts dislocations from the crystal bulk by forming pits on the crystal growth plane. These pits act as dislocation sinks, causing dislocations to concentrate and terminate at the pit regions, thereby removing them from the main crystal structure and achieving uniform low dislocation density across the substrate plane.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces localized pit structures at specific positions on the crystal growth plane. These pits create localized regions with different dislocation characteristics, allowing dislocations to be managed in specific areas while maintaining high-quality crystal regions elsewhere, thus achieving uniform overall dislocation distribution.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If multiple pits are formed on the crystal growth plane to reduce dislocations, then dislocations are reduced in regions other than the pits, but multiple pit regions with high dislocation density remain

Engineering Contradiction:

Improvedislocation density in crystal bulkVSAvoiddislocation density in pit regions

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent converts the harmful effect of dislocations into a beneficial process by intentionally forming pits that attract and concentrate dislocations. The pits serve as controlled defect regions that protect the main crystal area, transforming the problem of dislocation management into a solution where dislocations are deliberately channeled to specific sacrificial zones.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Area of stationary object

If a large-sized crystal substrate is fabricated, then the utilization efficiency is improved, but achieving low dislocation density becomes more difficult

Engineering Contradiction:

Improvesubstrate areaVSAvoiddislocation density

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent segments the crystal growth plane into multiple regions with pits distributed across the large substrate area. This segmentation allows each region to independently manage dislocations through its local pit structures, enabling the fabrication of large-sized substrates while maintaining low and uniform dislocation density across the entire area.

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

The method enables the production of AlxGayIn1-x-yN crystal substrates with a suitable dislocation density range, enhancing the properties of semiconductor devices by maintaining a balance between dislocation density and crystallinity, thereby improving the performance and reliability of semiconductor devices.

Implementation Method 1

at least some of dislocations remaining in the AlxGayIn1-x-yN crystal are propagated in a direction substantially parallel to a crystal growth plane of the AlxGayIn1-x-yN crystal so as to be released to an outer periphery of the AlxGayIn1-x-yN crystal

Methodology Applied

Scientific EffectDislocation propagation:

Data Source

PatentUS7943964B2AlxGayIn1−x−yN crystal substrate, semiconductor device, and method of manufacturing the same

Publication Date: 2011.05.17 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

An AlxGayIn1-x-yN crystal substrate of the present invention has a main plane having an area of at least 10 cm2. The main plane has an outer region located within 5 mm from an outer periphery of the main plane, and an inner region corresponding to a region other than the outer region. The inner region has a total dislocation density of at least 1×102 cm−2 and at most 1×106 cm−2. It is thereby possible to provide an AlxGayIn1-x-yN crystal substrate having a large size and a suitable dislocation density for serving as a substrate for a semiconductor device, a semiconductor device including the AlxGayIn1-x-yN crystal substrate, and a method of manufacturing the same.