Layered Substrate With Polycrystalline Heat Spreader for Epitaxial Uniformity

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Solution Overview

Problem

Existing epitaxial growth processes face challenges in achieving uniform temperature distribution across the substrate surface, leading to defects such as dislocations and stacking faults due to thermal inhomogeneities, which affect the quality of semiconductor components.

Innovation Solution

A layered substrate comprising a monocrystalline growing layer and a polycrystalline heat spreader substrate with thermally coupled grains is used to equalize temperature profiles, mitigating thermal inhomogeneities and improving the quality of epitaxial layers by enhancing thermal stability and reducing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional substrate is used for epitaxial growth, then the substrate can be easily manufactured, but thermal inhomogeneities occur leading to defects in epitaxial layers

Engineering Contradiction:
Improvequality of epitaxial layersVSAvoidsubstrate structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The substrate is constructed as a composite structure combining a monocrystalline layer and a polycrystalline heat spreader layer. The monocrystalline layer provides a defect-free template for epitaxial growth, while the polycrystalline heat spreader layer distributes thermal energy uniformly across the substrate surface, eliminating thermal inhomogeneities that cause defects in epitaxial layers.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The substrate is divided into functionally distinct layers: a monocrystalline growing layer for high-quality epitaxial deposition and a polycrystalline heat spreader layer for thermal management. This segmentation allows each layer to perform its specific function optimally, with the monocrystalline layer ensuring low defect density and the polycrystalline layer ensuring uniform temperature distribution.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the substrate temperature is not uniformly distributed, then the epitaxial deposition rate varies, but adjusting the reactor temperature profile increases energy consumption

Engineering Contradiction:
Improveuniformity of epitaxial layerVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The thermal management function is extracted from the reactor temperature control system and transferred to the substrate itself through the polycrystalline heat spreader layer. This layer actively distributes thermal energy at the substrate level, decoupling the uniformity of epitaxial layer deposition from the reactor's energy consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a monocrystalline substrate is used, then the epitaxial layer quality is high, but the substrate cannot compensate for thermal variations

Engineering Contradiction:
Improvedefect density in epitaxial layersVSAvoidthermal compensation capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The substrate combines monocrystalline and polycrystalline materials to achieve both low defect density and thermal compensation. The monocrystalline layer ensures high reliability for epitaxial growth by providing a perfect crystal template, while the polycrystalline heat spreader layer adds adaptability by compensating for thermal variations through its superior thermal conductivity and heat distribution properties.

Inventive Principle:
Principle #40Composite materials

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 layered substrate design results in improved thermal uniformity, reducing defects and impurities in epitaxial layers, thereby enhancing the quality and performance of semiconductor devices.

Implementation Method 1

the heat spreader substrate comprises a polycrystalline material having thermally coupled grains that are piled in the direction of growth, the piled grains for equalizing hot spots of the reactor thermally coupled to the mounting surface

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4632118A1Layered substrate, method of fabrication of a layered substrate and method for growing an epitaxial layer with the layered substrate
Publication Date: 2025.10.15 SICRYSTAL GMBH
  • EP4632118A1 patent drawingFigure 1
  • EP4632118A1 patent drawingFigure 2~3
  • EP4632118A1 patent drawingFigure 4~5

AI summary

The present disclosure relates to a layered substrate for growing an epitaxial layer in a direction of growth (Y) in a reactor. The layered substrate comprises a monocrystalline growing layer (110) with a growing surface (112) for growing the epitaxial layer and an opposing heat spreader facing surface (114) for coupling the growing layer (110) to a heat spreader substrate (140). The layered substrate further comprises the heat spreader substrate (140) with a growing layer facing surface (144) for coupling to the heat spreader facing surface (114) and an opposing mounting surface (142) for mounting the heat spreader substrate (140) to the reactor, wherein the heat spreader substrate (140) comprises a polycrystalline material having thermally coupled grains (146) that are piled in the direction of growth (Y), the piled grains (146) for equalizing hot spots of the reactor thermally coupled to the mounting surface (142).