SiC Epitaxial Growth Layout for Full Seed Area Coverage

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Solution Overview

Problem

The sublimation sandwich method (SSM) for growing SiC monocrystals is limited by the inability to grow on the entire seed area due to the face-down configuration of the seed, which hinders the production of substrates with standard shapes and diameters required for semiconductor applications.

Innovation Solution

A system and method where the source material is arranged above the substrate in a face-up configuration, supported by separate structures, allowing the entire substrate surface to be exposed to the source material, with different leg heights for the source and substrate supports to maintain optimal temperature distribution and growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the seed is loaded above the source in a face-down configuration with a spacer, then the growth process can be maintained, but the grown area is always smaller than the original seed area, preventing growth on the entire seed

Engineering Contradiction:

Improvegrown area coverageVSAvoidseed configuration flexibility

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent inverts the conventional face-down seed configuration to a face-up configuration. The seed crystal is positioned with its growth surface facing upward, allowing the entire seed area to be exposed to the vapor phase and receive uniform deposition, thereby achieving growth across the complete seed area without spacer limitations.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent removes the spacer component that was previously necessary to maintain the gap between seed and source. By extracting this limiting element and adopting a face-up configuration with the source positioned above, the system enables growth across the entire seed area without the constraints imposed by spacer geometry.

Inventive Principle:

Principle #2Taking out (Extraction)

2Area of stationary object

If the source and substrate are supported by separate structures with different leg heights, then the entire substrate surface is exposed to the source material, but the support structure complexity increases

Engineering Contradiction:

Improveexposed substrate surface areaVSAvoidsupport structure complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The support structure is segmented into multiple legs of different heights. The source support has longer legs while the substrate support has shorter legs, creating the necessary vertical separation. This segmentation allows the entire substrate surface to be exposed to the source material vapor while maintaining structural simplicity through a modular leg-based design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the support structure have different heights tailored to their specific functions. The source support legs are longer to position the source material at an optimal height for vapor generation, while the substrate support legs are shorter to keep the substrate at the appropriate deposition plane, ensuring maximum surface exposure without excessive complexity.

Inventive Principle:

Principle #3Local quality

3Productivity

If the growth temperature is maintained at around 2000°C for high growth rate, then the growth rate reaches around 150 μm/h, but the energy consumption increases

Engineering Contradiction:

Improvegrowth rateVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent replaces conventional heating methods with radio frequency (RF) induction heating. This electromagnetic heating technique directly induces eddy currents in the graphite crucible and source material, generating heat more efficiently and locally at the required 2000°C growth temperature, thereby achieving high growth rates with reduced overall power consumption compared to traditional resistive or flame heating.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12486596B2System and method of producing monocrystalline layers on a substrate

Publication Date: 2025.12.02 KISELKARBID I STOCKHOLM AB

AI summary

A system (100) for producing an epitaxial monocrystalline layer on a substrate (20) comprising: an inner container (30) defining a cavity (5) for accommodating a source material (10) and the substrate (20); an insulation container (50) arranged to accommodate the inner container (30) therein; an outer container (60) arranged to accommodate the insulation container (50) and the inner container (30) therein; and heating means (70) arranged outside the outer container (60) and configured to heat the cavity (5), wherein the inner container (30) comprises a support structure for supporting a solid monolithic source material (10) at a predetermined distance above the substrate (20) in the cavity (5) such that a growth surface of the substrate (20) is entirely exposed to the source material (10). A corresponding method is also disclosed.