SiC Semiconductor Substrate Lamination via Reaction-Sintered Body
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Solution Overview
Problem
Conventional methods for manufacturing silicon carbide (SiC) semiconductor substrates face challenges such as high manufacturing costs and physical property limitations, particularly in bonding single-crystal SiC substrates to polycrystalline SiC substrates, which affect the performance and reliability of devices like Schottky barrier diodes, MOSFETs, and IGBTs.
Innovation Solution
A method involving reaction-sintering of an aggregate of SiC and Si/C powders to form a polycrystalline SiC sintered body, which is then carbonized to create a SiC sintered body layer laminated on a single-crystal SiC layer, eliminating the need for normal temperature bonding or diffusion bonding and reducing warping issues, while ensuring corrosion and oxidation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-crystal SiC substrate is bonded to polycrystalline SiC substrate to reduce manufacturing costs, then manufacturing cost is reduced, but warping occurs and structural integrity deteriorates
Solution Approach 1:
The invention changes the material composition parameters of the sintered body by controlling the ratio of SiC particles to free Si (specifically setting free Si content to 5-20 wt%), which modifies the thermal expansion coefficient and bonding characteristics. This parameter optimization allows the sintered body to bond to single-crystal SiC substrates with minimal warping while maintaining cost-effectiveness through the reaction sintering process.
Solution Approach 2:
The invention creates a composite sintered body material consisting of SiC particles embedded in a free Si matrix. This composite structure combines the advantages of both materials: SiC provides high-temperature stability and chemical resistance, while free Si provides ductility and reduces thermal stress. The resulting composite sintered body achieves both cost reduction and structural integrity.
2Ease of manufacture
If reaction-sintering method is used to fabricate SiC sintered body, then manufacturing cost is reduced, but corrosion resistance and oxidation resistance are compromised
Solution Approach 1:
The invention optimizes the composition parameters of the sintered body by precisely controlling the free Si content (5-20 wt%) and SiC particle distribution. This parameter control ensures that the material maintains adequate corrosion and oxidation resistance while achieving cost-effective manufacturing through the reaction sintering process. The free Si content is kept within a specific range to prevent excessive oxidation.
Solution Approach 2:
The invention applies local quality by creating a heterogeneous structure where SiC particles (providing corrosion and oxidation resistance) are distributed within a free Si matrix (providing structural integrity and cost-effectiveness). This local differentiation of material properties allows different regions of the sintered body to fulfill different functional requirements simultaneously.
3Strength
If normal temperature bonding or diffusion bonding is used to bond substrates, then structural integrity is maintained, but manufacturing cost increases and warping occurs
Solution Approach 1:
The invention changes the bonding interface parameters by optimizing the surface composition and structure of the sintered body. By controlling the free Si content and distribution, the bonding surface achieves optimal adhesion to single-crystal SiC substrates at lower temperatures, eliminating the need for expensive normal temperature bonding or diffusion bonding processes while preventing warping.
Solution Approach 2:
The invention replaces expensive, complex bonding processes (normal temperature bonding or diffusion bonding) with a simpler, more cost-effective reaction sintering process. The sintered body acts as a cost-optimized substrate that can be directly bonded to single-crystal SiC without requiring additional expensive bonding layers or processes.
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
This approach reduces manufacturing costs, improves yield, and enhances the structural integrity and performance of SiC semiconductor substrates by creating a robust, corrosion-resistant, and oxidation-resistant sintered body layer that supports the formation of high-quality semiconductor devices like Schottky barrier diodes, MOSFETs, and IGBTs.
Implementation Method 1
reaction-sintering of an aggregate of SiC and Si/C powders to form a polycrystalline SiC sintered body
Implementation Method 2
ensuring corrosion and oxidation resistance
Implementation Method 3
ensuring corrosion and oxidation resistance
Data Source
AI summary
A molding is formed by laminating an aggregate of SiC and a paste containing Si and C powders on an epitaxial layer of SiC formed on a support substrate of SiC to form an intermediate sintered body in which polycrystalline SiC is produced from the Si and C powders by reaction sintering, free Si is carbonized to SiC to form a sintered body layer, and the support substrate is removed from the epitaxial layer to form a semiconductor substrate in which the epitaxial layer and the sintered body layer are laminated.