Silicon carbide is a compound synthesized from carbon and silicon, possessing unique chemical and physical properties. Silicon carbide comes in various crystal forms, with the common ones being tetragonal and hexagonal structures, referred to as 4H-SiC and 6H-SiC. These structures allow silicon carbide to adapt to different environments and purposes.
Silicon carbide has an exceptionally high thermal conductivity, even surpassing most metals, and its hardness is second only to diamond, making it an ideal material for high-temperature and high-pressure environments.
Overall, the unique properties of silicon carbide play a significant role in modern technology, especially in fields like electric vehicles, renewable energy systems, and communication infrastructure. In summary, silicon carbide is not just a fascinating material but also a key factor in driving innovation across various industries.
The manufacturing process of silicon carbide wafers is intricate. Here is a brief overview of the process:
Raw Material and Silicon Carbide Crystal Growth: Initially, pure silicon and carbon materials are needed. These materials react at high temperatures to grow silicon carbide crystals. This process typically uses Physical Vapor Deposition (PVD) or Chemical Vapor Deposition (CVD) techniques.
Crystal Cutting and Polishing: Once the silicon carbide crystals are grown, they are cut into thin slices, known as wafers. These wafers are then precisely polished to ensure a smooth and flawless surface.
Doping: Doping is a critical step to alter the electrical properties of the wafer. By introducing trace amounts of other elements (like phosphorus or boron) into the silicon crystal, the wafer’s conductivity can be controlled.
Lithography and Etching: Lithography is a technique that uses light to transfer a pattern onto the wafer’s surface. After lithography, chemical or plasma etching techniques are used to remove unwanted material, forming circuit patterns.
Deposition of Insulating and Metal Layers: Insulating and metal layers are deposited on the wafer to form circuit connections and gate structures.
Packaging: Finally, the manufactured wafer is packaged into a usable component. This involves installing the wafer into a package and connecting it to external wiring.
The entire process requires precise control and highly clean room conditions to avoid any minute impurities or dust affecting the wafer’s performance. Silicon carbide wafers, with their excellent performance under high temperatures, high voltages, and high frequencies, are particularly suitable for high-end power electronics.