Silicon carbide (SiC) power devices
A wider bandgap material that is reshaping the traction inverter market.
- Explain silicon carbide (sic) power devices at engineering level
- Read the numbers that define the behaviour
- Apply the idea to a real drive system
Overview
Silicon carbide MOSFETs have gone from a laboratory curiosity to the default choice in premium and increasingly mainstream EV inverters within a decade, because the material itself is simply better suited to the job.
In depth
| Property | Silicon | Silicon carbide |
|---|---|---|
| Bandgap | 1.1 eV | 3.3 eV |
| Breakdown field strength | ~0.3 MV/cm | ~2.8 MV/cm |
| Max junction temperature | ~150 °C | ~200+ °C |
| Thermal conductivity | 1.5 W/cm·K | 3.7 W/cm·K |
| Typical switching frequency | 5–15 kHz (IGBT) | 10–40+ kHz |
A higher breakdown field means a SiC device can be made much thinner for the same voltage rating, which directly lowers on-resistance. Higher thermal conductivity moves heat out of the die faster, and a higher maximum junction temperature gives more thermal headroom before derating — three separate advantages stacking together.
Lab · Configure an inverter
Choose between IGBT and SiC devices and see the effect on loss and junction temperature directly.
Inverter loss has two parts. Conduction loss depends on the device's on-state resistance or saturation voltage and the current through it. Switching loss depends on the energy lost in each transition multiplied by how often you switch. Silicon carbide has far lower switching energy than an IGBT, which is what allows higher switching frequencies and smaller filters.
Key takeaways
- SiC's wider bandgap gives higher breakdown field, better thermal conductivity and higher max temperature.
- These properties translate into lower conduction and switching loss at the same voltage rating.
- The efficiency gain from switching to SiC is measurable in real-world range.
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