I talk to hardware engineers every week who are designing new power stages. The same question comes up again and again: “Should I go SiC or GaN?”
And almost every time, the real question behind the question is: which choice avoids a painful redesign eighteen months from now?
Here’s the honest answer — and it’s simpler than most articles make it sound.
The One Sentence Version
SiC is for high voltage. GaN is for high frequency. That’s it.
If your bus voltage is above 650V, choose SiC. If your switching frequency needs to be above 1 MHz, choose GaN. In the vast majority of real-world designs, this single heuristic gives you the right answer.
The rest of this article explains why that heuristic works, and what to do in the narrow overlap zone where both technologies compete.
Why This Heuristic Works: The Physics in Plain English
Both SiC and GaN are “wide bandgap” materials — meaning their atomic structure handles high electric fields much better than silicon. But they handle it in different ways that matter enormously for your design.
SiC has extraordinary thermal conductivity. At 370 W/m·K, it conducts heat almost three times better than GaN (130 W/m·K). This means a SiC MOSFET can sit on a heatsink in an EV inverter, handle 200 amps continuously at 800V, and keep its junction temperature manageable. When your device dissipates serious power and can’t afford to melt, SiC’s thermal advantage is the deciding factor.
GaN has extraordinary switching speed. GaN transistors produce zero reverse recovery charge — their switching transitions are purely capacitive. This means they can switch at 5 or 10 MHz without the ringing and loss that would cripple a silicon or even SiC device at those frequencies. When you can switch faster, your magnetics get smaller. Dramatically smaller. And in a data center PSU or a 65W USB-C charger, that size reduction is everything.
The heuristic works because these advantages are rooted in material physics. SiC’s thermal conductivity doesn’t go away, and GaN’s switching speed doesn’t go away. The physics dictates the application.
The Numbers That Matter
For the engineers who want specifics:
SiC MOSFETs are commercially available from 650V to 3300V. Infineon’s latest CoolSiC 750V G2 series hits 40 mΩ on-resistance while handling 47A and operating up to 175°C. These are AEC-Q101 qualified parts going into production EV inverters right now.
GaN HEMTs top out at 650V commercially, but within that range they’re remarkably efficient. EPC’s EPC2218 (100V, 3.2 mΩ) enables point-of-load converters for AI server processors at 5 MHz+, shrinking the inductor volume by 80%. Infineon’s CoolGaN 600V series pushes server PSU efficiency to 97.5%.
Neither technology is standing still, but their trajectories reinforce rather than undermine the heuristic. SiC is pushing toward higher voltages (1700V, 3300V). GaN is pushing toward higher frequencies (10 MHz+). They’re diverging, not converging.
The Gray Zone: 400–650V Applications
There’s a real overlap zone, and this is where engineering judgment replaces simple rules.
On-board chargers for electric vehicles often operate at 400–650V. At this voltage, both technologies are technically feasible. So how do you choose?
Ask three questions:
Is your power level above 5 kW? If yes, lean toward SiC. The thermal management challenge at high power is much easier to solve with SiC’s superior heat conduction. You can use a simpler heatsink, maybe skip the fan, and still hit your thermal targets.
Is extreme power density your primary design constraint? If yes, lean toward GaN. The higher switching frequency lets you use physically smaller inductors and capacitors. If shrinking the power stage by 40% is worth the extra gate driver complexity, GaN delivers.
Is this your team’s first wide bandgap design? If yes, lean toward SiC. SiC MOSFETs behave like familiar MOSFETs — they’re voltage-driven with a standard gate structure. GaN HEMTs are different beasts. Enhancement-mode GaN requires careful attention to gate overdrive limits (typ. 6V max), and the absence of a body diode means dead-time management matters much more. The learning curve is real.
What About Cost?
A common misconception: “SiC is expensive and GaN is cheap.” The reality is more nuanced.
Yes, a 1200V SiC MOSFET costs $4.50–$8.00 at 1000 pieces, versus $2.80–$5.50 for a 650V GaN HEMT. But device cost alone is misleading.
GaN’s high switching frequency shrinks passive components — often by 60–80% in volume. A 10 µH inductor for a 150 kHz SiC converter might cost $2 and occupy 200 mm² of PCB. The equivalent function at 2 MHz with GaN needs a 0.47 µH inductor costing $0.40 and occupying 25 mm². Multiply this across six power stages and the BOM-level economics can invert.
SiC’s thermal advantage plays the same game in reverse. The heatsink you didn’t need, the fan you didn’t buy, the enclosure you didn’t upsize — these “saved costs” accumulate.
The honest answer: at system level, in their respective sweet spots, both technologies are cost-competitive with silicon IGBTs above 1 kW. The price premium objection is largely outdated as of 2026.
Supply Chain Reality
For procurement teams, two things matter: lead times and second-source options.
SiC lead times are longer. The industry is transitioning from 150mm to 200mm wafers, which creates temporary capacity friction. Expect 16–26 weeks for automotive-grade SiC MOSFETs from Wolfspeed, Infineon, STMicro, or onsemi. Budget accordingly.
GaN lead times are shorter. GaN-on-Si devices leverage mature silicon wafer infrastructure. Lead times typically run 8–16 weeks, and Infineon’s move to 300mm GaN-on-Si production is driving costs down rapidly. The supply base includes EPC, Navitas, Texas Instruments, and Infineon.
If supply security is a concern — and in 2026, it should be — GaN’s broader manufacturing base and shorter lead times are a genuine advantage for sub-650V designs.
The One Thing to Watch: Vertical GaN
There’s a technology in the lab that could disrupt this clean separation: vertical GaN. Unlike today’s lateral GaN HEMTs that top out at 650V, vertical GaN promises 900V+ ratings with GaN’s switching speed advantage intact.
Companies like VisIC are demonstrating promising results. If vertical GaN achieves commercial qualification (likely 2028–2030), it could challenge SiC in the EV inverter market.
For procurement decisions you’re making in 2026? Vertical GaN is a future consideration, not a present option. Design with what’s qualified and shipping today.
Bottom Line
If someone asks you “SiC or GaN?” and you have ten seconds to answer:
- Above 650V → SiC. No question.
- Below 650V, high frequency → GaN. No question.
- 400–650V, moderate frequency → Depends on power level and thermal environment. But now you know the three questions to ask.
Both technologies are excellent. Neither replaces the other. The engineers who understand this — and the procurement teams who can reliably source both — will build the most competitive power systems of this decade.
Need SiC or GaN power semiconductors? Cosolvic sources from Wolfspeed, Infineon, STMicro, EPC, and Navitas. Request a quote with your voltage, current, and package requirements.