Gallium nitride vs Silicon carbide
Gallium nitride and Silicon carbide are genuine alternatives to one another — a choice somebody actually makes — and differ on 2 measured properties, density most clearly.
Gallium nitride vs Silicon carbide
Gallium nitride
GaN
The semiconductor that made blue light possible, and is now making phone chargers small — a wide band gap, and thirty years of work to grow it on anything.
Silicon carbide
SiC
A synthetic ceramic close to diamond in hardness, and the first commercially successful manufactured abrasive.
| Property | Gallium nitride | Silicon carbide |
|---|---|---|
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | hexagonal | hexagonal |
| Density | 6.15 g/cm³ higher | 3.21 g/cm³ |
| Melting point Only one of the two has a figure we can stand behind, so there is nothing to compare. | 2500 °C | Not known |
| Mohs hardness Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 9–9.5 |
| Molar mass | 83.73 g/mol higher | 40.1 g/mol |
| Refractive index Only one of the two has a figure we can stand behind, so there is nothing to compare. | 2.4–2.5 | Not known |
| Thermal conductivity Only one of the two has a figure we can stand behind, so there is nothing to compare. | 130–230 W/(m·K) | Not known |
Choosing between them
Gallium nitride is recorded as a substitute for Silicon carbide — cheaper.
What it gives up: A lateral device on a foreign substrate, so heat leaves it less readily and it does not scale to the kilovolt-class traction inverters silicon carbide holds.
In this application, on the evidence cited above.