Silicon Carbide (SiC) substrates have quickly become an essential element in power devices due to their superior properties. When compared with traditional silicon wafers, SiC substrates boast superior thermal conductivity and can withstand higher breakdown electric fields than their silicon counterparts.
SiC can be formed into various crystalline structures known as polytypes; three of the most widely-used semiconductor applications involve 3C-SiC and 4H-SiC materials.
High Thermal Conductivity
Silicon Carbide (SiC) is an effective wide bandgap semiconductor material, offering numerous advantages for power applications such as handling higher temperatures and voltages more effectively, and with greater thermal conductivity dispersing heat more quickly reducing cooling systems needs and making smaller more compact devices possible.
Many manufacturers are turning to SiC substrates in their production processes, though their large sizes can prove challenging for workability – potentially impacting cleavage and machining performance as well as producing subpar wafers that could have an adverse impact on device performance.
Recently, researchers from Osaka Metropolitan University Graduate School of Engineering demonstrated for the first time that 3C-SiC exhibits high thermal conductivity – equal to that of diamond. Utilizing atomic-level analysis techniques, these researchers determined that this material’s second simplest crystal structure after diamond has an exceptional thermal conductivity among large diameter materials.
The team discovered that SiC’s thermal conductivity depends on its phonon mean free path, which measures collisions of heat-carrying phonons. This pathway can be affected by factors like grain size, alloying elements, impurities, vacancies and crystal defects – including stacking faults – but by controlling stacking faults it can be managed and thermal conductivity improved.
High Strength
Silicon carbide’s strength does not decrease with rising temperatures, particularly its solid-phase sintered version (SSiC), which retains both Mohs hardness of 9.5 and electrical semiconductivity. Furthermore, its resistance to corrosion, abrasion and erosion allows production of components designed to endure challenging environments in applications like 3D printing, ballistics, energy technology paper manufacturing chemical processing pump and motor parts.
Due to its low thermal expansion, SSiC makes an excellent material for mirrors in astronomical telescopes, with light weight and rigidity making telescope mirrors up to 3.5m (11ft). When compared with metal mirrors, it is much lighter, easier to handle, and more reflective.
Silicon carbide’s insulating properties allow it to be used in power semiconductor devices, where its superior efficiency over traditional silicon materials allows it to make power devices more energy-efficient. Particularly, it provides wide-bandwidth characteristics at high currents and voltages to minimize switching losses and energy loss in power transmission systems. Electric vehicle charging and renewable energy generation systems benefit greatly from high voltage switching devices that optimize power conversion efficiency, helping increase range, decrease charge times, and ensure efficient power conversion. They also enhance performance in high voltage devices for power electronics by prolonging lifespan and increasing current capacity – particularly important when considering their harsh environmental conditions.
Low Coefficient for Thermal Expansion
Silicon carbide is an extremely hard and resistant material with a low coefficient for thermal expansion and corrosion resistance, making it perfect for demanding conditions like 3D printing, ballistics production and paper manufacturing. Furthermore, silicon carbide is non-toxic with a high strength-to-weight ratio.
Edward G. Acheson of America discovered silicon carbide by accident when attempting to synthesize artificial diamonds. While heating a mixture of clay and powdered coke in an iron bowl with a carbon electrode at high temperatures, bright green crystals formed that were similar in hardness to diamond. He named this newly created compound Carborundum which later became SiC.
Silicon carbide ceramics can be formed into shapes through various sintering molding methods that vary depending on the substrate material’s properties. Hot pressing sintering and direct sintering are two widely-used processes for producing silicon carbide substrates with various resistivity levels: semi-insulating substrates have low resistivity levels while n-type silicon carbides offer lower resistance levels.
Optic components made from silicon carbide are growing increasingly popular across industries, yet its strength, stress levels and other design parameters depend on manufacturing method used. Therefore, it’s vital that when selecting the appropriate silicon carbide substrate for your application you fully comprehend its nuances.
Low Resistivity
Silicon carbide has the capacity to withstand extremely high temperatures without reacting with acids or alkalis, while also being resistant to mechanical stress and cracking – qualities which make it an ideal material for mechanical seals that must perform under extreme temperatures and stress.
Silicon carbide’s low electrical resistivity makes it suitable for many applications, including power electronics devices and semiconductor processing parts. Furthermore, it boasts lower thermal conductivity than sapphire while being manufactured into different polytypes that enable control over its electrical resistivity.
Silicon carbide is a semiconductor material, so doping can easily create either an n-type or p-type structure. Doping usually uses nitrogen or phosphorus for its doping needs while beryllium, boron, or aluminium are typically utilized for its p-type doping applications. Doping options help control electrical resistance making porous silicon carbide more beneficial in various applications.
Silicon carbide’s crystalline structure also contributes to its low electrical resistivity, as it allows conductive pathways between carbon and silicon atoms. Furthermore, this structure makes silicon carbide isotropic; that is, its electrical and thermal properties remain consistent across its dimensions for better control over resistivity in porous silicon carbide products.
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