Silicon Carbide Seed Single Crystal SiC Seed Wafer PVT Method

Silicon Carbide Seed Single Crystal SiC Seed Wafer PVT Method

About Silicon Carbide (SiC) Single Crystal:

Silicon carbide is a compound formed by C and Si elements. At present, more than 200 kinds of silicon carbide homogeneous and special-shaped crystal structures have been found. Among them, 4H SiC with hexagonal structure has the advantages of high critical breakdown electric field and high electron mobility. It is an excellent semiconductor material for manufacturing semiconductor devices with high voltage, high temperature and anti-irradiation power. It is also the third generation semiconductor material with the best comprehensive performance, the highest degree of commercialization and the most mature technology. Compared with the physical properties of silicon materials, the main characteristics include: 

*The critical breakdown electric field intensity is nearly 10 times that of silicon materials.

*High thermal conductivity, more than 3 times that of silicon material.

*The drift velocity of saturated electrons is high, which is twice that of silicon.

*Good radiation resistance and chemical stability.

*Like silicon materials, silicon dioxide insulating layer can be directly grown on the surface by thermal oxidation process.

The Crystal Structure of SiC:

    SiC is a IV-IV compound semiconductor material composed of Carbon and Silicon in a stoichiometric ratio of 1:1, and its hardness is second only to diamond.

Both Carbon and Silicon atoms have 4 valence electrons, which can form 4 covalent bonds. The basic structural unit of SiC crystal, SiC tetrahedron, arises out of the tetrahedral bonding between Silicon and Carbon atoms. The coordination number of both Silicon and Carbon atoms is 4, i.e. each Carbon atom has 4 Silicon atoms around it and each Silicon atom also has 4 Carbon atoms around it.

    As a crystal material, SiC Substrate also has the characteristic of periodic stacking of atomic layers. The Si-C diatomic layers are stacked along [0001] direction.Due to the small difference in bond energy between layers, different connection modes are easily generated between atomic layers, leading to over 200 SiC polytypes. Common polytypes include 2H-SiC, 3C-SiC, 4H-SiC, 6H-SiC, 15R-SiC, etc. Among them, the stacking sequence in the order of "ABCB" is called the 4H polytype. Although different polytypes of SiC have the same chemical composition, their physical properties, especially the bandgap width, carrier mobility and other characteristics are quite different. And the properties of 4H polytype are more suitable for semiconductor applications.

Growth Method of SiC Single Crystal:

    At present, the most mature method for growing silicon carbide single crystal is physical vapor transport (PVT). Its growth mechanism is that carbon powder and silicon powder are sublimated and decomposed into gaseous substances such as Si atoms, Si2C molecules, and SiC2 molecules at a high temperature of more than 2000°C. Driven by the temperature gradient, these gaseous substances will be transported to the silicon carbide seed crystal with lower temperature to form 4H silicon carbide crystal. Specific 4H SiC crystal forms can be grown by controlling the process parameters such as temperature field and gas flow of PVT.

Applications of SiC Single Crystal:

ZMSH Product Recommendation: 6-Inch Silicon Carbide (SiC) Wafer for AR glasses MOS SBD

     Silicon Carbide (SiC) single crystal is a wide-bandgap semiconductor material known for its high breakdown voltage, excellent thermal conductivity, high electron mobility, and outstanding chemical and mechanical stability.Because of these exceptional properties, SiC single crystals are widely used in high-power, high-frequency, high-temperature, and harsh-environment applications across multiple industries. SiC single crystals are the foundation of third-generation semiconductor technology, enabling high-efficiency, compact, and durable electronic systems.Their combination of wide bandgap, high thermal conductivity, and superior strength makes them indispensable in power electronics, RF communication, automotive, renewable energy, aerospace, and photonics industries.

Q&A:

Q: Is SiC a crystal?

A: Silicon carbide (SiC), also known as carborundum, is a hard chemical compound containing silicon and carbon. A wide bandgap semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal since 1893 for use as an abrasive.

Q: What is the purpose of a seed crystal?

A: Seed crystals are defined as high-quality single crystals used to initiate crystal growth and prevent multi-nucleation by providing a new growth interface. They are typically of the same composition as the desired crystal and play a crucial role in producing larger crystals with specific crystallographic orientations.

Q: What is the process of growth of SiC crystals?

A: Physical vapor transport growth. PVT is the most commonly adopted method for the growth of SiC crystals. It mainly includes three steps: sublimation of the SiC source, transport of the sublimates and surface reaction and crystallization of the seed crystal.