Transition from Silicon (Si) to Silicon Carbide (SiC) in Power Electronic Devices

As we all know, silicon (Si) material and the technologies based on it have changed the world. Derived from sand, silicon material has been used to build products far more intricate and sophisticated than sandcastles. Now, silicon carbide (SiC) material, as a derivative technology, has entered the market. Compared to silicon, it enables higher power-level power conversion, faster switching speeds, and superior heat transfer efficiency. This blog explores how SiC material enhances product performance to surpass silicon-based domains, thereby creating next-generation solutions for our new digital world.

Silicon-based MOSFETs, silicon carbide (SiC) MOSFETs, gallium nitride (GaN) HEMTs, or silicon carbide (SiC) FETs are primary technical components used in various market sectors for power electronic devices. Silicon has long been the preferred semiconductor material for power electronic applications. Only recently, due to the significant improvement in SiC technology performance and reliability, people have started to shift from silicon to SiC devices.

The performance advantages of SiC have had a profound impact on multiple power electronics markets, including electric vehicles, white goods, infrastructure, solar/renewable energy, data centers, etc. Thanks to its larger bandgap energy (3.3eV, compared to silicon’s 1.1eV—see Figure 2) and higher breakdown voltage, SiC can be used to create novel, higher-performance solutions.

Today, manufacturers are adopting SiC technology to develop power electronic modules based on various semiconductor devices, such as bipolar junction transistors (BJT), junction field-effect transistors (JFET), and metal-oxide-semiconductor field-effect transistors (MOSFET). In the following sections, we will explore why SiC is becoming a breakthrough power electronics technology for the future.

• SiC vs. Si Adoption: Comparative AdvantagesFirstly, SiC MOSFET or SiC FET has several advantages compared to silicon devices. The higher breakdown voltage of SiC means that thinner and lighter devices can be used to support higher voltages. Additionally, other advantages of SiC over silicon include:
  • As a wide-bandgap material, lower leakage current at high temperatures.
  • Higher thermal conductivity, aiding high current density applications.
  • Lower energy losses, helping minimize power dissipation.
  • Higher switching frequency, reducing the size and weight of large peripheral passive components.
  • Smaller die size and lower parasitic capacitance result in lower switching losses, enabling power converters to operate at higher switching frequencies and speeds.
  • Ability to operate at higher ambient temperatures, contributing to reduced heatsink size.

  Thus, we can now see the numerous advantages of SiC devices over silicon-based devices, making it a compelling choice for many applications transitioning from silicon to SiC.

• Understanding the Electro-Thermal Advantages of SiCIn the field of power electronics, effectively reducing or minimizing power losses in high-power applications has always been crucial. Similarly, meeting thermal design requirements under extreme conditions is also essential. SiC not only meets these requirements but also has a Drain-to-Source On-Resistance (RDS(ON)) that is 300 to 400 times lower than silicon devices. This figure of merit (FOM) is a boon for manufacturers, as it allows them to design highly efficient power electronic devices. Furthermore, under the same effective die area, silicon carbide (SiC) devices can handle higher power levels than silicon (Si) based devices. In other words, SiC devices can achieve the same power level conversion with smaller chip sizes.

  Additionally, SiC boasts higher thermal conductivity and fast switching capabilities, along with lower output capacitance and RDS(ON). Because SiC devices can handle higher energy levels and theoretically achieve higher switching frequencies, they can help manufacturers save on system costs. Why? Because these FOMs mean that the sizes of passive components, such as transformers, choke coils, and inductors—essential in all switch-mode power supply designs—can be significantly reduced. All these FOMs imply that SiC devices will play a significant role in applications like three-phase inverters, digital power supplies, and power electronic converters (AC/DC and DC/DC).

  Efficiency is another FOM pursued by manufacturers today. Given the global push for “green” energy initiatives, efficiency has become a key driving factor in many applications. Figure 1 below illustrates that SiC can achieve higher efficiency compared to silicon, making it the preferred technology in many next-generation designs.

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SiC and other wide-bandgap semiconductor technologies are the ideal choice for the next generation of efficient power electronic devices (see Figure 2). SiC demonstrates excellent voltage blocking capability starting from 650V, and its advantages become more significant at higher voltages. A crucial step in building the next-generation solutions is the establishment of “green” (i.e., high energy efficiency) systems. SiC can provide this capability—its wide-bandgap characteristics enable higher power efficiency, smaller size, lighter weight, and lower overall costs—equivalent to a more environmentally friendly solution.

Conclusion

Currently, we have gained a deeper understanding of the comparison between Si and SiC. In our rapidly evolving digital world, both have their places in numerous applications; however, SiC demonstrates superior performance in many solutions. SiC technology finds wide applications in power electronic solutions. Due to its extensive gate drive range, adopting SiC in high-frequency applications like DC/DC and AC/DC brings numerous advantages. Additionally, using SiC in electric vehicle inverters offers lower conduction losses and robust short-circuit handling capabilities.

The continuous advancement of SiC technology will drive its expansion into more applications and extend its reach into other fields. Simultaneously, improvements in packaging design, increased market acceptance, and the rapid growth of market space will further facilitate the application of SiC technology in a broader range of solutions.