In our latest post, we’re going to discuss bandgaps and find out why SiC’s wide bandgap is key to its usefulness.
When it comes to conduction and insulation, there are two types of bands within a material: the conduction band and the valence band. In order for an electron to be conducted, it needs enough energy to bridge the bandgap between the valence band and the conduction band. Materials that are conductors have conduction and valence bands that either overlap or have a very small bandgap, while insulators have an extremely wide gap.
The bandgap refers to the energy difference between the top of the valence band and the bottom of the conduction band. Another way of expressing it is that the bandgap represents the amount of energy needed for an electron to successfully make the jump between the valence band and the conduction band. Because semiconductors can both conduct and insulate, they will always have a non-zero bandgap that lies somewhere between what you would see with an insulator and a conductor.
The bandgap represents energy and is measured in eV (electron volts, a unit of energy equal to approximately 1.602×10−19 J). The bandgap of SiC is 3.26 eV, compared to that of Si at 1.12 eV or GaAs (Gallium Arsenide) at 1.42 eV. SiC, therefore, is referred to as having a wide bandgap.
Wide bandgap semiconductor materials such as SiC offer many advantages over more traditional semiconductor materials (such as Si). Consider the fact that a bandgap shrinks as temperatures rise: if we start with a wide bandgap, then rising temperatures will have far less effect on functionality. Because SiC has a wide bandgap, it can continue to function in much higher temperatures, often up to 400°C.
Heat can also be distributed more effectively with SiC, often eliminating the need for fans and heat sinks. When it comes to design with SiC, systems will be more compact, exhibit better efficiency, and require smaller-sized magnetics for power applications. This is all, at least partly, thanks to the benefits that come directly from SiC’s wide bandgap.
Components made from SiC are faster, smaller, and more reliable than those made from its counterparts. The wider bandgap of SiC facilitates switching larger voltages. Components made with wide bandgap semiconductors such as SiC also operate at significantly higher voltages, power levels, and frequencies. SiC components have higher operating speeds, and power components made with SiC also offer improved efficiency for DC-DC, AC-DC, and DC-AC conversion.
Because SiC has a much wider bandgap than other semiconductor materials such as Si or GaAs, it possesses some critical advantages, including the ability to handle higher voltages and power, higher operating temperatures, faster switching, better efficiency, and a significantly smaller form factor. SiC components have been proven ideal for challenging applications such as those involving hybrid and electric vehicles, renewable energy, power factor boost correction, uninterruptible power supplies, down-hole drilling for the petrochemical industry, and much more.
