Monocrystalline SiC Thin-Layer Transfer on Crystallized SiC Carrier
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Solution Overview
Problem
The challenge lies in manufacturing high-quality composite structures with a thin layer of monocrystalline silicon carbide (c-SiC) on a lower-quality carrier substrate made of silicon carbide, while avoiding the complexities and costs associated with existing methods, such as surface activation bonding and high-temperature processes that lead to defects and blistering.
Innovation Solution
A process involving ion implantation to create a buried brittle plane, followed by successive crystalline carrier layer formations using direct liquid injection chemical vapor deposition and crystallization heat treatments below 900°C, allowing for the separation of a composite structure with a thin c-SiC layer on a polycrystalline SiC carrier substrate, and including mechanical and chemical treatments to enhance quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct bonding is used to assemble monocrystalline SiC thin layer with polycrystalline SiC carrier substrate, then vertical electrical conduction is enabled, but high-quality direct bonding is difficult to achieve due to complex surface state and roughness management
Solution Approach 1:
An intermediate layer is introduced between the monocrystalline SiC thin layer and the polycrystalline SiC carrier substrate to facilitate bonding. This intermediate layer acts as a mediator that simplifies the bonding process by reducing the complexity of surface state and roughness management, while still enabling vertical electrical conduction through the composite structure.
Solution Approach 2:
The bonding process utilizes parameter changes in the intermediate layer, such as controlling its thickness, composition, and physical properties, to optimize both the bonding quality and electrical conduction. By adjusting parameters like deposition temperature, layer thickness, and material composition, the method achieves high-quality bonding without complex surface management.
2Strength
If surface activation bonding with argon bombardment is used to promote covalent bonds, then bonding energy is increased, but an amorphous layer is generated at the surface of monocrystalline SiC donor substrate which negatively affects vertical electrical conduction
Solution Approach 1:
The intermediate layer serves as a protective mediator that prevents the formation of detrimental amorphous layers on the monocrystalline SiC surface during bonding processes. It allows for sufficient bonding energy to be achieved while maintaining the crystalline structure and electrical properties of the donor substrate surface.
Solution Approach 2:
The method applies preliminary protective measures by introducing the intermediate layer before bonding occurs. This preliminary action prevents the harmful effect of amorphous layer formation that would otherwise occur during surface activation processes, thereby preserving vertical electrical conduction pathways.
3Reliability
If high temperature processes are used for carrier substrate manufacturing, then carrier substrate quality is improved, but defects and blistering occur that reduce composite structure quality
Solution Approach 1:
The method employs optimized temperature parameters and controlled heating rates during carrier substrate manufacturing to achieve high substrate quality without excessive defects or blistering. By carefully controlling thermal parameters and using the intermediate layer as a buffer, the process maintains material integrity while ensuring carrier substrate performance.
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 process enables the production of high-quality composite structures with reduced defect density and improved electrical conductivity, facilitating the use of lower-cost carrier substrates and reducing the complexity and cost of the manufacturing process.
Implementation Method 1
implanting light ions and assembling by direct bonding
Implementation Method 2
direct liquid injection chemical vapor deposition
Implementation Method 3
crystallization heat treatment of the carrier layer
Implementation Method 4
separating along the buried brittle plane
Data Source
AI summary
A method for manufacturing a composite structure comprising a thin layer made of monocrystalline silicon carbide arranged on a carrier substrate made of silicon carbide, the method comprising: a) a step of providing a donor substrate made of monocrystalline silicon carbide, b) a step of ion implantation of light species into the donor substrate, to form a buried brittle plane delimiting the thin layer between the buried brittle plane and a free surface of the donor substrate, c) a succession of n steps of forming crystalline carrier layers, with n greater than or equal to 2; the n crystalline carrier layers being positioned on the front face of the donor substrate successively one on the other, and forming the carrier substrate; each formation step comprising: direct liquid injection chemical vapor deposition, at a temperature below 900° C., to form a carrier layer, the carrier layer being formed by an at least partially amorphous SiC matrix, and having a thickness of less than or equal to 200 microns; a crystallization heat treatment of the carrier layer, at a temperature of less than or equal to 1000° C., to form a crystalline carrier layer; d) a step of separation along the buried brittle plane, to form, on the one hand, a composite structure comprising the thin layer on the carrier substrate and, on the other hand, the rest of the donor substrate.