As a supplier of silicon carbide (SiC) materials, I get this question every day from engineers, researchers, and industry contacts who are just starting to dive into wide-bandgap semiconductors: “What is the electrical conductivity of SiC?” The answer isn’t a single number, and that’s one of the things that makes SiC such a powerful material for modern electronics. Let me break this down in plain terms, from what conductivity actually means, to how we control it at our facility, and why it matters for the products you’re building. SiC
First, let’s start with basics: electrical conductivity measures how easily electric current flows through a material. It’s the opposite of resistivity, so a high conductivity number means a material lets current pass easily—think copper or aluminum, which have very high conductivity. SiC, though, is a semiconductor, so its conductivity sits somewhere between conductive metals and insulators like glass. But unlike silicon (the traditional workhorse of semiconductors), SiC’s conductivity is far more tunable, and that’s why so many of our clients choose our material for high-power, high-temperature, or high-frequency applications.
At its core, intrinsic SiC (pure, un-doped, no extra atoms added) has a very low conductivity. The bandgap of SiC is around 3.2 electron volts (eV)—three times larger than silicon’s 1.1 eV. What that means for conductivity is that it takes a lot more energy to knock an electron loose and create a charge carrier (the particle that carries current) in pure SiC. At room temperature, intrinsic SiC has a conductivity of roughly 10^-10 S/cm (siemens per centimeter). That’s extremely low—close to an insulator, which makes pure SiC useless for most electronics on its own. This is where doping comes in, and this is where our expertise as a SiC supplier comes in.
Doping is the process of adding tiny amounts of other atoms to SiC’s crystal structure to change its conductivity. We use two main types of doping, just like silicon: n-type and p-type. N-type doping adds atoms with one extra valence electron, which become free charge carriers that move current. For SiC, the most common n-type dopant is nitrogen. When we add nitrogen to the SiC crystal, it replaces a silicon atom in the lattice and donates one electron, creating free carriers. As we increase the concentration of nitrogen, the conductivity goes up. For n-type SiC, typical conductivity ranges we can produce are from 10 S/cm for lightly doped material up to 10,000 S/cm (10^4 S/cm) for heavily doped, low-resistivity grades. That’s a huge range, perfect for different parts of a device—like a substrate for power transistors, or a conductive layer for electrodes.
P-type doping, on the other hand, adds atoms with one fewer valence electron, creating “holes” (positive charge carriers) that also carry current. The standard p-type dopant for SiC is aluminum. Similar to n-type, increasing aluminum concentration raises conductivity. Our p-type SiC conductivity ranges from around 1 S/cm up to about 1,000 S/cm. It’s a bit lower than n-type SiC at the same doping levels because the hole mobility in SiC is slightly lower than electron mobility, a material property we’ve learned to account for in our production processes.
But here’s the thing: conductivity isn’t just about doping. Temperature also plays a huge role, and this is where SiC beats silicon in a lot of applications. For metals, conductivity decreases as temperature goes up—more heat makes atoms vibrate, which blocks electron flow. For semiconductors, though, it’s the opposite: at moderate temperatures, conductivity increases as temperature rises, because more electrons get knocked loose from atoms, creating more charge carriers. With silicon, this effect happens over a fairly narrow temperature range, and at temperatures above 200°C, conductivity starts to drop as the number of charge carriers gets so high that they start colliding with each other. SiC can handle much higher temperatures. Even at 500°C, our SiC materials still maintain stable, high conductivity, whereas silicon would become almost useless at that point. That’s why SiC is the go-to material for electric vehicle inverters, aerospace electronics, and industrial power equipment that runs in hot environments.
Another factor that affects conductivity is polytype. SiC isn’t a single material—it has multiple crystal structures called polytypes, the most common being 4H-SiC, 6H-SiC, and 3C-SiC. Each polytype has slightly different bandgaps and carrier mobilities, which changes conductivity. 4H-SiC is the most widely used for power electronics right now, with higher electron mobility than 6H-SiC, so for the same doping level, 4H-SiC has higher conductivity. That’s why most of the wafers we ship are 4H-SiC, tailored to our clients’ specific conductivity needs. 3C-SiC, while less common, has even higher electron mobility, so it can achieve very high conductivity at lower doping levels, but it’s more difficult to produce in large, high-quality wafers.
Now, let’s talk about what this means for our customers. When a power electronics engineer is designing an inverter for an electric car, they need different conductivity levels for different parts. The substrate (the base that supports the transistors) needs high conductivity to spread heat and carry current, so they’ll use a heavily doped n-type SiC with conductivity around 1,000 to 5,000 S/cm. The active channel of the transistor, though, needs a lower conductivity, lightly doped SiC, because that’s where the current is switched on and off. If the channel was too conductive, the transistor wouldn’t turn off properly. Our job as a supplier is to work with you to pick the right conductivity grade, and even custom-dope material if your application needs something outside our standard ranges.
I’ve seen a lot of manufacturers come to us with the wrong expectation: they think SiC conductivity is a fixed number, like copper, and they’re surprised when we explain how tunable it is. That’s the advantage, though—SiC’s conductivity can be adjusted to match exactly what your design requires, which isn’t possible with many other materials. We recently worked with a team building a satellite component that runs at 300°C; they needed a p-type SiC with consistent conductivity over that temperature, because temperature fluctuations in space would throw off a material with unstable conductivity. We produced a custom p-type grade with a conductivity of 100 S/cm, which stayed within 5% of that value from -40°C to 400°C, and that’s a testament to how we refine our doping processes to get stable, reliable conductivity.
Of course, there are limits. You can’t make SiC as conductive as copper or silver, and for applications where you need extreme conductivity, you’d still use metal. But for semiconducting applications, SiC’s conductivity range is perfect, and its other properties—high breakdown voltage, thermal conductivity, and resistance to radiation—make it irreplaceable in many cases. Our thermal conductivity, for example, is another big reason customers choose us: even with moderate conductivity, SiC dissipates heat much better than silicon, which means your device runs cooler and lasts longer.
I also want to address a common misconception: conductivity isn’t the only metric that matters. A material with high conductivity but low purity isn’t useful, because defects in the crystal structure can trap charge carriers, lowering actual conductivity. That’s why all of our SiC wafers are grown with strict quality control, to minimize defects and ensure that the conductivity we measure is the actual conductivity you’ll get in your final product. We test every ingot and wafer at multiple points during production, so you can be sure that the material we ship matches the specifications we agree on.
If you’re just starting out with SiC, or if you’ve been using it and need a material with a specific conductivity level, the best way to get the right answer is to talk through your application with someone who knows SiC inside and out. We don’t just sell wafers and substrates—we work with engineers to solve problems. Whether you’re building a high-voltage inverter for renewable energy, a motor drive for heavy equipment, or a component for aerospace, we can help you pick the right SiC conductivity grade, adjust it if needed, and deliver a consistent, high-quality product.
If you need to source SiC materials that meet your exact conductivity and performance requirements, reach out to our team to discuss your project. We can provide sample materials for testing, walk you through our production processes, and tailor a solution that fits your needs. Don’t settle for off-the-shelf SiC when you can work with a supplier that understands how conductivity impacts your end product.
ESD References:
- Kimoto, T., & Matsunami, H. (2014). Fundamentals of Silicon Carbide Technology: Growth, Characterization, Devices and Applications. John Wiley & Sons.
- Neamen, D. A. (2003). Semiconductor Physics and Devices: Basic Principles (3rd ed.). McGraw-Hill.
- Itoh, T., & Kimoto, T. (2015). "Silicon Carbide Power Devices: Recent Progress and Future Prospects". Japanese Journal of Applied Physics, 54(4), 040101.
Tongke Electronic Co., Ltd
Tongke Electronic Co., Ltd. is one of the most experienced sic manufacturers and suppliers in China, featured by quality products and low price. Please rest assured to wholesale advanced sic made in China here from our factory. Contact us for pricelist.
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