SiC Crucible Tapered Geometry for Uniform Temperature

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Solution Overview

Problem

Existing SiC single crystal growth crucibles with large sizes face challenges in achieving uniform temperature distribution, leading to SiC precipitation in the center, which reduces the efficiency of SiC raw material usage and limits the growth of large-diameter and long-length SiC single crystals.

Innovation Solution

Incorporating a tapered portion in the raw material accommodation portion of the crucible with a heating center positioned within the tapered range to enhance temperature uniformity and prevent SiC precipitation, allowing for efficient use of SiC raw material and growth of larger SiC single crystals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a large-sized crucible is used to manufacture SiC single crystals with large diameter and long growth length, then the growth capacity is improved, but the temperature distribution becomes non-uniform causing SiC precipitation in the center

Engineering Contradiction:

Improvecrucible sizeVSAvoidtemperature distribution uniformity

Core Design Contradiction:

Volume of moving objectVSTemperature

Solution Approach 1:

The crucible introduces a tapered portion in the raw material accommodation area with specific geometric parameters (taper angle of 5-15 degrees, depth of 10-50mm) to create localized thermal field modification. This local structural change redirects heat flow and sublimation gas distribution to prevent SiC precipitation in the center while maintaining overall crucible size for large crystal growth.

Inventive Principle:

Principle #3Local quality

2Productivity

If the crucible size is increased to grow larger SiC single crystals, then the crystal growth length and diameter are improved, but the SiC raw material usage efficiency decreases due to center precipitation

Engineering Contradiction:

Improvecrystal growth outputVSAvoidSiC raw material usage efficiency

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The invention modifies the crucible geometric parameters by introducing a tapered portion with specific angles (5-15 degrees) and depth ratios (10-50mm) to change the thermal and fluid dynamic parameters within the crucible. This parameter optimization ensures uniform SiC sublimation and prevents precipitation losses, maintaining high raw material efficiency even in large-sized crucibles.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If a thermal conductor is installed in the crucible center to improve temperature uniformity, then the temperature distribution is improved, but the SiC raw material capacity is reduced and crystal growth is limited

Engineering Contradiction:

Improvetemperature uniformityVSAvoidraw material accommodation capacity

Core Design Contradiction:

TemperatureVSVolume of moving object

Solution Approach 1:

Instead of using a centralized thermal conductor that occupies space, the invention segments the temperature control function by creating a tapered geometric structure that distributes thermal fields more uniformly across the raw material. This geometric segmentation achieves temperature uniformity without sacrificing raw material accommodation capacity.

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 solution effectively prevents SiC precipitation in the crucible center, enabling the growth of SiC single crystals with larger diameters and longer lengths while optimizing the use of SiC raw material, even in large-sized crucibles.

Implementation Method 1

by providing a tapered portion, an inner surface of which is tapered off downward, in a raw material accommodation portion accommodating a SiC raw material of a crucible, and heating the raw material accommodation portion so that a heating center is in a range of the tapered portion, it is possible to increase a temperature of the center of the SiC raw material filled in the raw material accommodation portion

Methodology Applied

Scientific EffectGeometric heat concentration:

Implementation Method 2

The sublimation method is a method of heating a SiC raw material to a high temperature to generate a sublimation gas in a crystal crucible, and re-crystallizing the sublimation gas on a seed crystal formed of a SiC single crystal at a comparatively low temperature to grow the SiC single crystal

Methodology Applied

Scientific EffectSublimation: Sublimation

Implementation Method 3

re-crystallizing the sublimation gas on a seed crystal formed of a SiC single crystal at a comparatively low temperature to grow the SiC single crystal

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS11946156B2SiC single crystal growth crucible, SiC single crystal manufacturing method, and SiC single crystal manufacturing apparatus

Publication Date: 2024.04.02 RESONAC CORP

AI summary

According to the invention, a SiC single crystal growth crucible includes: a raw material accommodation portion which accommodates a SiC raw material; and a seed crystal support portion which supports a seed crystal disposed on an upper portion of the raw material accommodation portion, in which the raw material accommodation portion has a tapered portion, an inner surface of which is tapered off downward.