Silicon Carbide Wafers (SCWs) are long-term semiconductor substrates designed for applications involving speed, high temperature and/or voltage requirements. SCWs provide excellent conditions for these uses.
Manufacturers produce cubic SiC through either ion implantation or chemical vapor deposition processes, as well as various polytypes characterized by different arrangements of atoms within the crystal structure.
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Silicon carbide (SiC) was initially introduced into industrial use in 1893 as an abrasive material for grinding wheels and automotive brakes, though since then its applications have expanded beyond these original uses to include many semiconductor applications. Thanks to its unique physical properties including high thermal conductivity and low thermal expansion rates, SiC offers an attractive alternative to more common wafer materials like silicon.
Due to its wide bandgap and higher critical breakdown electric field strength, silicon carbide can handle higher temperatures and power densities than silicon. Furthermore, its greater saturated electron drift velocity enables higher switching frequencies and faster power conversion efficiency.
Photolithography, the process for creating intricate circuit patterns onto wafers, exposes SiC substrates to UV light through masks containing desired circuit patterns. After exposure, depending on the type of photoresist used, exposed and unexposed areas change chemically over time and result in transference of that pattern onto a wafer.
Precision etching is the final step in wafer fabrication, where excess material is removed by precise removal. SiC substrate has very few etching defects, making it ideal for demanding applications like EV power electronics and 5G electronics where imperfections could hinder device performance. MTI instruments allow manufacturers to monitor quality during these steps with tools like X-ray topography, photoluminescence mapping and scanning electron microscopy.
High Resistance to Thermal Shock
Silicon carbide wafers can withstand thermal shocks very well, maintaining strength and stability over a wide temperature range while outperforming silicon in power semiconductor applications.
SiC’s resilience against rapid temperature shifts stems from its structure: strong tetrahedra composed of silicon and carbon atoms. This structure offers excellent acid resistance, corrosion protection, pressure stability and does not react with molten salts or acids at temperatures up to 800degC – characteristics which distinguish SiC from other materials.
Silicon carbide’s high temperature stability enables it to be highly resistant to chemical media, making it an excellent material choice for industrial abrasives and automotive brakes. Furthermore, mechanical abrasion damage resistance makes silicon carbide even more resilient against impact damage than its competitors.
Silicon carbide is the second hardest material in the world after diamond. Furthermore, its high temperature stability makes silicon carbide an excellent candidate for ceramics and enamels.
Silicon carbide’s superior performance properties make it the perfect candidate for future developments within the power semiconductor industry. As Moore’s Law approaches its limits, many companies are turning to silicon carbide to provide their devices with performance and reliability they require. Thanks to its high electrical conductivity and resistance to chemical attack at temperatures, silicon carbide has quickly become one of the top choices for wafer tray supports and paddles used in semiconductor furnaces as well as components like thermistors and varistors.
High Hardness
Silicon carbide wafers possess an exceptionally hard surface that is indispensable to many devices. Microchips for example require hardness within certain limits in order to avoid cracking during fabrication and operation; similarly devices requiring high temperature durability and radiation resistance also benefit from its superior hardness.
SiC wafers boast exceptional thermal shock resistance, making them suitable for fast temperature changes without breaking or cracking, making them especially suitable for power electronics and RF applications.
Silicon Carbide wafers boast excellent wear resistance. SiC can be found in bulletproof vest plates or extrusion dies designed for materials like sandpaper and high-performance disc brakes, providing reliable wear resistance. SiC also boasts excellent radiation shielding properties as well as having a high melting point and energy bandgap, contributing further to its physical durability.
SiC can be hardened through doping, alloying, and surface treatment methods such as solid solution doping or ion implantation; surface treatments include coating and plating to increase hardness, reduce wear, and improve lubrication. Furthermore, its hardness may also be enhanced by controlling its grain size and uniformity; adding harder compounds or powders near grain boundaries further increase hardness by impeding dislocation propagation.
High Electrical Conductivity
Combining silicon from sand with carbon from coal yields an astonishing result: silicon carbide. This revolutionary compound semiconductor material has found use in applications requiring exceptional performance such as power electronics and radio frequency (RF) devices.
Silicon carbide wafers meet these stringent requirements with ease, boasting three times higher thermal conductivity than their more widely known cousin, silicon.
SiC wafers boast superior thermal performance over silicon wafers, enabling them to operate at higher operating temperatures while providing greater heat dissipation, making it the ideal substrate for power-intensive applications that operate at elevated temperatures.
For example, electric vehicle inverters require working at extremely high voltages and dissipating significant heat efficiently to achieve this task. SiC excels in this respect – its strength allows it to withstand even extreme high voltages with ease while providing superior performance such as increased energy efficiency and power density.
For manufacturing silicon carbide wafers, manufacturers typically employ physical vapor deposition or chemical vapor deposition methods to form cubic crystals of pure silicon that are then cut and polished into wafers that can then be polished and cleaned into ultra-flat surfaces for device fabrication. Precise control over thickness and doping facilitates powerful device manufacturing with increased yield, lower defect costs, and greater reliability.
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