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An Engineer's Guide to High Reliability Components 18 What is Silicon Carbide? In the field of power electronics, one of the most fundamental components is the FET, typically used as a switching device in power circuits such as amplifiers, switched-mode power supplies, inverters, and motor drives. Historically, power FETs are made of silicon (Si), a staple in the industry for decades. However, the trend toward higher voltages, currents, densities, and temperatures is causing Si-based power FETs to reach their limits in terms of performance and reliability. As a result, many engineers are starting to adopt SiC-based FETs as a worthy alternative. A wide-bandgap semiconductor, SiC offers several improved material properties compared to those of Si. These properties include improved switching characteristics, higher efficiency, better thermal stability, and higher breakdown voltages. Compared to Si, SiC has a 5–10x higher breakdown voltage, 3x higher thermal conductivity, and a 2x higher electron saturation velocity. Thus, SiC FETs offer significantly improved performance, especially in high-voltage, high-current power electronic applications. Silicon Carbide for Greater Reliability Owing to improved material properties, SiC-based FETs offer greater reliability for analog power electronics. One way SiC provides higher reliability is through improved thermal performance. On a material level, SiC is much more stable than Si at higher temperatures, meaning it does not need significant derating to continue safe operation. This stability allows for better performance at high temperatures. Further, because of the wide bandgap of SiC, SiC-based FETs can exhibit extremely high thermal stability, resulting in devices that can safely be used at junction temperatures reaching more than 200ºC. By operating with high performance at extreme temperatures, SiC can enable unprecedented levels of reliability for power circuits and designs as a whole. Beyond thermal tolerance, SiC tolerates higher voltages. With a higher breakdown voltage than Si, SiC is less likely to fail due to transient voltage spikes and power surges, making it a more robust and reliable solution. As a corollary to this advantage, power systems built on SiC may require less surface complexity for reliable operation, potentially enabling designs with simpler layouts, fewer components, and, ultimately, less chance of failure. Because of its improved efficiency, SiC enables more reliable designs. Thanks to its improved switching characteristics and decreased on-resistances, SiC enables the creation of FETs that dissipate much less power than Si alternatives. This reduced dissipation is not only beneficial in terms of power savings but also device reliability; with less power consumption, SiC FETs will generate less heat, resulting in fewer component and device-level thermal failures.